True or False: Positive ions have more electrons than protons
O True
O False

Answers

Answer 1

Answer:

If the atom has more electrons than protons, it is a negative ion, or ANION. If it has more protons than electrons,it is a positive ion.

Explanation:

so yes true

Answer 2
It is true. positive ions have more electrons than protons =3


Related Questions

THIS dUe NOW HELP PLS

THIS dUe NOW HELP PLS

Answers

A I promise you ....
The answer is A. This means out of place.

grace measures 20mL of water in a graduated cylinder. she puts a piece of rock in the
graduated cylinder and measures the new volume of water to be 32mL. what is the volume of
the rock?

Answers

The volume would be explanation times explanation because the explanation is the explanation

Explanation:

Answer:

\(\boxed {\boxed {\sf v=12 \ mL}}\)

Explanation:

Grace found the volume of the rock using water displacement.

To calculate the volume, we must subtract the initial volume from the final volume.

\(v_f-v_i\)

The initial or original volume is 20 milliliters.

The final or new volume, after the rock is added to the water, is 32 milliliters.

\(v_f=32 \ mL\\v_i=20\ mL\)

Substitute the values into the formula and subtract.

\(32 \ mL-20 \ mL\)

\(12 \ mL\)

The volume of the rock is 12 milliliters.

What does the slope of each line tell you about the warming of the can? - If there was a graph.

(Use science terminology)


(We did an experiment seeing whether a black can or a silver can would absorb more radiation, the black can did)

Answers

The slope of the line on a graph of temperature over time for the black can would represent the rate at which the temperature of the can was increasing, while the slope of the line for the silver can would represent the rate at which the temperature of the can was increasing.

Since the black can absorbed more radiation than the silver can, it would have a steeper slope than the silver can, indicating a higher rate of temperature increase over time. This is because the black can absorbed more heat energy from the radiation than the silver can, causing its temperature to increase more rapidly. Therefore, the slope of the line for the black can would tell us that it was warming up more quickly than the silver can, as a result of absorbing more radiation.

Two protons and two neutrons are released as a result of this reaction. Superscript 222 subscript 86. Rn Right arrow superscript 218 subscript 84. Po ? Which particle is released? one alpha particle two beta particles one alpha and one beta particle one high-energy photon.

Answers

The particle released in the reaction has been an alpha particle. Thus, option A is correct.

The release of protons and neutrons in a reaction has been nuclear reactions. The reactions results in the change in the atomic mass of the atom, with the formation of new atom. The extra mass has been released in the form of energy.

The release from the given reaction has been:

\(\rm ^{222}_{66}Rn\;\rightarrow\;^{218}_{84}Po\;+\;^A_ZX\)

Where, X has been the particles that has been released with the nuclear reaction. The superscript A has been the Mass of particle, and subscript Z has been the atomic number.

According to the law of conservation, the mass has been constant on both the product and the reactant side. Thus, the mass and atomic number of eliminated particles has been given as:

\(\rm 222=218+A\\A=222-218\\A=4\)

The atomic mass of the particle has been 4.

\(\rm 86=84+Z\\Z=86-84\\Z=2\)

The atomic number of the particle has been 2.

The element with atomic mass 4, and atomic number 2 has been the Helium particles, \(\rm ^4_2He\). It has been an alpha particle. Thus, the particle released in the reaction has been an alpha particle. Thus, option A is correct.

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Answer:

A

Explanation:

A student places a starch and water solution into a bag of dialysis tubing and then ties off the ends. Next, he places the filled bag into a beaker of distilled water. Water will now ________ the bag by the process of ________.

Answers

Answer:

After 30 minutes have passed, the solution inside the dialysis tubing and the solution in the beaker will be tested for glucose and starch

-The presence of glucose will be tested with Benedict's solution, Testape®, or Clinistix

What is the concentration of H+ ions at a pH = 2?
mol/L
What is the concentration of OH– ions at a pH = 2?
mol/L
What is the ratio of H+ ions to OH– ions at a pH = 2?
: 1

What is the concentration of H+ ions at a pH = 2? mol/L What is the concentration of OH ions at a pH

Answers

Answer:

0.01M = [H⁺]; 1x10⁻¹²M = [OH⁻]; Ratio is: 1x10¹⁰

Explanation:

pH is defined as -log [H⁺]

For a pH of 2 we can solve [H⁺] as follows:

pH = -log [H⁺]

2 = -log [H⁺]

10^-2 = [H⁺]

0.01M = [H⁺]

Using Keq of water:

Keq = 1x10⁻¹⁴ = [H⁺] [OH⁻]

1x10⁻¹⁴ / 0.01M = [OH⁻]

1x10⁻¹²M = [OH⁻]

The ratio is:

[H⁺] / [OH⁻] = 0.01 / 1x10⁻¹² =

1x10¹⁰

Answer:

1. 0.01 mol/L

2. 0.000000000001 mol/L

3. 10000000000:1

Explanation:

Which two elements have the same number of valence electrons
Element Atomic number
barium 56
neon 10
silicon 14
carvon 6

Answers

The elements that have the same number of valence electrons are silicon and carbon. The answer is option C and D. An element is a pure substance that cannot be separated into any simpler substances by chemical means. The periodic table is made up of elements.

These are some of the characteristics of an element: All atoms of an element have the same number of protons in their nucleus, which is the atomic number. The majority of an element's properties are determined by the number of electrons in its outermost shell. This is also referred to as the valence shell. Silicon and carbon both have four valence electrons. They both belong to Group 14, which is also known as the Carbon Group, on the periodic table, which includes elements with four valence electrons. Therefore, Silicon and Carbon both have the same number of valence electrons. The answer is option C and D

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I NEED HELP PLS ILL GIVE BRAINLY

I NEED HELP PLS ILL GIVE BRAINLY

Answers

The correct statement about Dunite is that it is formed when magma cooled slowly below the ground; Option B.

What are rocks?

Rocks are large aggregates of minerals that occur in the earth's crusts as a result of the cooling ad solidification of molten magma or the deposition of the remains of dead organic matter which changes from pressure ad heat.

There are three types of rocks, and they are:

Igneous rocks - formed by the cooling of molten magma e.g. Dunite, a light yellowish-green, intrusive igneous rockSedimentary rocks - formed from the remains of dead organic matterMetamorphic rocks - are formed from changes that occur in sedimentary rocks.

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Thinking and questioning is the start of the scientific inquiry process

Answers

Explanation:The scientific inquiry process is the process in which scientists or researchers find an explanation for any natural world phenomena with logic and evidence collected by the systemic method or work. The scientific inquiry process begins with a question or thinking (observation) for any natural phenomena like why freshwater has low albedo where ice has a high albedo percentage.

Which of these are ionic compounds? Check all that apply. a. NH_4Cl b. SrO c. SO_2 d. BrCl

Answers

The ionic compounds are substances composed of positive and negative ions. Let's check which among the given compounds are ionic compounds NH4Cl.

This is an ionic compound. It is formed by the reaction between ammonium (NH4+) and chloride (Cl-) ions. SrO This is an ionic compound. It is made up of strontium (Sr2+) and oxide (O2-) ions. SO2 This is not an ionic compound. It is a molecular compound that consists of sulfur (S) and oxygen (O) atoms.

BrCl This is not an ionic compound. It is a molecular compound that contains bromine (Br) and chlorine (Cl) atoms. Therefore, the ionic compounds among the given compounds are a) NH4Cl and b) SrO.

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The volume of gas in a balloon is 1.90 L at 21.0o C. The balloon is heated, causing it to expand to a volume of 5.70 L. What is the new temperature of the gas inside the balloon?

Answers

The new temperature of the gas inside the balloon : 609 °C

Further explanationCharles's Law  

When the gas pressure is kept constant, the gas volume is proportional to the temperature  

\(\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\)

The balloon is heated, causing it to expand (pressure constant) :

V₁=1.9 L

T=21+273=294 K

V₂=5.7 L

\(\tt T_2=\dfrac{T_1\times V_2}{V_1}\\\\T_2=\dfrac{294\times 5.7}{1.9}\\\\T_2=882 K=609 ^oC\)

Find the oxidation number-> Oxidation number of O in PbO2

Answers

Explanation:

The name for the compound PbO₂ is lead (IV) oxide. The oxidation state of lead is +4 and the oxidation state of oxygen is -2. Actualy the oxidation state of oxygen in oxides is always -2.

Answer: the oxidation state of O in PbO₂ is -2.

Find the oxidation number-> Oxidation number of O in PbO2

The oxidation number of oxygen in the compound PbO₂ is -2. The oxidation number of an atom can be positive, negative, or zero.

Let's assume that the oxidation number of lead (Pb) is x and the oxidation number of oxygen (O) is y. The compound PbO₂ is neutral, which means the sum of the oxidation numbers must be zero.

The oxidation number of Pb is known to be +4 because PbO₂ is lead dioxide, whereas oxygen is typically assigned an oxidation number of -2.

Thus,

(+4) + 2(y) = 0

4 + 2y = 0

2y = -4

y = -2

Therefore, the oxidation number of oxygen (O) in PbO₂ is -2.

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A tin of chopped tomatoes weighs 145 grams.
You buy four of these tins.
What is the total mass of these four tins
i in grams
cont.
b
ii in kilograms?

Answers

The total mass of 4 tin is in grams is 580 grams and in kg is 0.58kg.

One tin of chopped tomatoes weight is 145 grams

and we have to calculate it for 4

so for 4

145*4 =580 grams

and we have to change it into kilograms so

580 /1000  = .58kg

By 1,000, divide the number of grams.

To convert from grams to kilograms, simply divide by 1,000 because there are 1,000 grams in every kilogram. If necessary, construct the equation using fractions. Put the number of grams over 1 and divide it by the conversion factor, which is 1 kg / 1,000 g. Your answer in kilograms will result from the cancellation of the grams. Remember to use the appropriate units to mark your response.

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Question 1 (2 points)
Which option can be classified as a pure substance?

Question 1 options:

heterogenous mixture


solution


homogenous mixture


compound

Question 2 (2 points)
Law of conservation of mass states that:

Question 2 options:

matter is destroyed


matter does not change


matter is neither created nor destroyed


matter is created

Question 3 (2 points)
What is a property of bases?

Question 3 options:

all of the above


Sour taste


Slippery touch


Ability to form hydronium ions+

Question 4 (2 points)
Which property do solutions with low pH values have?


What does it mean to have a neutral pH? - Aseptic Health

Question 4 options:

have a -OH group


feels slippery


turns litmus paper blue


tastes sour

Question 5 (2 points)
How do the products of chemical reactions compare to their reactants?

Question 5 options:

The products often have completely different properties than the reactants.


The products are usually more toxic than the reactants.


The products usuallyhave more mass than the reactants.


The products usually have more atoms than the reactants.

Question 6 (2 points)
Which of the following is an example of a physical change?

Question 6 options:

Water freezing into ice.


A piece of wood burning.


A toy car rusting.


Zinc producing hydrogen gas when mixed with water.

Question 7 (2 points)
What might happen if you mixed a strong acid with an equally strong base?

Question 7 options:

You would see an explosive chemical reaction.


The base would destroy the acid.


You'd wind up with a pH-neutral salt and water.


The acid would destroy the base.

Question 8 (2 points)
In the equation shown, what are the reactants?

2H2+O2àH2O

Question 8 options:

Hydrogen and oxygen molecules (2H2 and O2 )


Ice crystals


Hydrogen atoms (H)


Water molecules (H2O)

Question 9 (2 points)
Which phrase most accurately describes a chemical change?

Question 9 options:

A change in form


A change in taste


A change on the molecular level


A change in appearance

Question 10 (2 points)
What does it mean when there is a physical change?

Question 10 options:

A new substance has been formed.


Matter has changed from one substance into a new substance.


Matter has changed size, shape or form


Matter has changed on the molecular level.

help pls ill give 20 points!

Answers

Answer:

I didn't KNOW WHAT IS THE ANSWWR OF YOUR QUISTION IM SO SORRY

Explanation:

I WANT TO INTRODUCE SELF TO YOU CAN I

5. find the concentration of 100.0 ml of hcl if 80.0 ml of 2.5 m naoh is required to neutralize the acid. a) how many moles of base were added to the beaker to neutralize the acid? b) how many moles of acid were originally in the beaker? c) using the original moles of acid and the original volume of acid in the flask, calculate the molarity of the hcl.

Answers

To find the concentration of HCl, we need to calculate the moles of base added to neutralize the acid, the moles of acid originally in the beaker, and then use these values to determine the molarity of HCl.

a) To find the moles of base (NaOH) added, we can use the formula:

Moles of NaOH = Volume of NaOH (in L) × Molarity of NaOH

Converting the volume to liters and using the given values:

Moles of NaOH = 0.080 L × 2.5 mol/L = 0.2 mol

b) Since the reaction is a 1:1 stoichiometric ratio between NaOH and HCl, the moles of acid (HCl) will be equal to the moles of base added. Therefore, there were also 0.2 mol of HCl originally in the beaker.

c) Now, we can calculate the molarity of HCl using the formula:

Molarity (M) = Moles of solute / Volume of solution (in L)

Given that the volume of the acid is 100.0 mL (or 0.100 L) and the moles of acid is 0.2 mol:

Molarity of HCl = 0.2 mol / 0.100 L = 2.0 M

Therefore, the molarity of the HCl solution is 2.0 M.

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A1 L sample from Tempe Town lake has a pH of 3. 57. Exhaust from cars on nearby highways

often mixes with rain to form HNO3. Use this information to answer the following questions.

1. What is the concentration of H+ ions in the sample?

2. If it took 80 ml of 1 M NaOH to neutralize 250 ml of the acidic solution, what is the

molarity of HNO3 in the sample?

3. How many moles of HNO3 are in the

solution?

Answers

Answer:

see explanations

Explanation:

1. pH = -log [H+]

so [H+] = 10^(-pH) = 10^(-3.57) = 2.7 x 10^(-4) M

2. neutralize implies mol acid = mol base

so [HNO3] = (1 M) * (0.080 L) / (0.250 L) = 0.32 M HNO3

3. mol HNO3 = molarity of HNO3 * volume of HNO3

= 0.32 M HNO3 * 0.250 L HNO3 = 0.080 mol HNO3

Why H2O leaves and many times readily?

Answers

Water, or H2O, leaves and evaporates readily due to its molecular structure and its ability to form hydrogen bonds. The hydrogen bonds between water molecules are relatively weak, allowing water molecules to break free from the liquid phase and enter the gas phase.

Additionally, water has a relatively low boiling point, meaning that it can easily be converted into a gas at normal temperatures. The process of evaporation is also affected by factors such as temperature, humidity, and air flow. When these factors are favorable, water molecules are more likely to leave the liquid phase and enter the gas phase.

Evaporation plays an important role in the water cycle, as it helps to transfer water from the earth's surface back into the atmosphere. It also has important applications in fields such as food preservation and cooling technology. Overall, the ability of H2O to leave and evaporate readily is due to a combination of its molecular structure and external factors that affect the process of evaporation.

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What is a volume​. in your own words but be more detailed about what you say.

Answers

Answer:

volume is the amount of space in a certain object

Suggest reasons why scientists are interested in studying earth's layers.

Answers

surely scientists

are in a competition of inventing how many things one can

Explanation:

some scientist are interested in in biology some are in astrology and many more

scientist are are interested

I NEED HELP ASAP RIGHT NOW PLEASE

I NEED HELP ASAP RIGHT NOW PLEASE

Answers

Answer:

I think it's C or D Sorry if I'm Wrong

Explanation:

it just makes the most sense to me

A 996.9 g sample of ethanol undergoes a temperature change of -70.98 °C while releasing 62.9
calories of heat. What is the specific heat capacity of ethanol?

Answers

Answer:

\(c=3.71\ J/g^{\circ} C\)

Explanation:

Given that,

Mass of sample, m = 996.9 g

The change in temperature of the sample, \(\Delta T=-70.98^{\circ}C\)

Heat produced, Q = 62.9  calories = 263173.6 J

The heat released by a sample due to change in temperature is given by :

\(Q=mc\Delta T\)

Where

c is the specific heat capacity

So,

\(c=\dfrac{Q}{m\Delta T}\\\\c=\dfrac{263173.6}{996.9\times 70.98}\\\\c=3.71\ J/g^{\circ} C\)

So, the specific heat of ethanol is equal to \(3.71\ J/g^{\circ} C\).

how many ml of water must be added to 300 ml of 0.75 m hcl to dilute the solution to 0.25 m? select one: a. 600 ml b. 100 ml c. 900 ml d. 300 ml

Answers

To dilute the solution to 0.25 M, ml of water must be added to 300 ml of 0.75 M HCl is a. 600 mm.

To dilute the solution from 0.75 M to 0.25 M, we need to decrease the concentration of HCl (hydrochloric acid) in the solution. We can use the formula for dilution of a solution to calculate the volume of water that must be added:

C1 * V1 = C2 * V2

Where:

C1 = initial concentration (0.75 M)

V1 = initial volume (300 ml)

C2 = final concentration (0.25 M)

V2 = final volume (V1 + V added)

Rearranging the equation to solve for V added:

C1 * V1 = C2 * V2

V2 = (C1 * V1 ) / C2

     = 0.75 * 300 / 0.25

     = 900

Since V2 = V1 + V added then

V added = V2 - V1

              = 900 - 300

              = 600

Hence, total water that must be added is a. 600 ml

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___________ is the least reactive metal.
i. Silver
ii. Iron
iii. Gold
iv. Sodium

Answers

Gold is the least reactive metal

Please help

Please answer this for me! I hope that it is clear enough and zoom in if you need too!! I will mark brainliest if you complete this for me :)

Please helpPlease answer this for me! I hope that it is clear enough and zoom in if you need too!! I

Answers

Answer:

1 atom of carbon on the reactant side (CH₄ is methane, 1 carbon, 4 hydrogen).

1 atom of carbon on product side (Law of Conservation of energy proves this).

4 hydrogen on reactant side (CH₄ is methane, 1 carbon, 4 hydrogen).

4 hydrogen on product side (Again, the Law of Conservation of energy proves this)

4 oxygen atom on the reactant side (2O₂ means two diatomic molecules, or two oxygen molecules of 2 atoms each).

4 oxygen atoms on the product side (Law of Conservation of energy).

2 molecules of oxygen on the reactant side.

2 molecules of water on the product side

Yes, the chemical equation is balanced. The amount of atoms is the constant on both the reactant and product side.

A Ionic bond is chemical bond between two oppositely charged ions because of the transfer of valence electrons between them.

A covalent bond is a chemical bond in which two or more atoms share electrons between them. They can also form polar covalent bond or non-polar covalent bonds (Although that depends on the electronegativities of the atom).

The bond of a carbon dioxide molecule is covalent bond (Polar covalent bond if you've learned that yet)

Potassium Fluoride (KFl) form an ionic bond.

2Al₂O₃ --> 4Al + 3O₂

A reducing agent loses electrons while and oxidizing agent gains electrons.

In an endothermic reaction, the total bond energy in the reactants is greater than the bond energy of products so energy is absorbed by the reaction. (For an endothermic reaction, more energy needs to be absorbed than released).

How many catalytic converters are in a dodge charger?.

Answers

Generally, a Dodge Charger has two catalytic converters, one located on each exhaust manifold.

A well-known American muscle automobile with an intimidating appearance is the Dodge Charger. The Charger has a long history that dates back to the 1960s and has emerged as a symbol of advanced automotive engineering. It has a variety of powerful V8 engines that give it remarkable acceleration and speed. Its unusual style, which blends vintage components with contemporary accents, draws both enthusiasts and collectors. The Charger's pedigree, performance, and eye-catching design have cemented its place as an enduring emblem of American muscle car culture.

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which of the following characteristics identifies a ph-balanced shampoo

Answers

The pH scale ranges from 0 to 14, with values below 7 considered acidic, 7 being neutral, and values above 7 being alkaline. Hair and scalp have a slightly acidic pH, and using a pH-balanced shampoo helps maintain the natural balance.

The characteristic that identifies a pH-balanced shampoo is having a pH level close to the natural pH level of the hair and scalp, which is around 4.5 to 5.5. Therefore, a pH-balanced shampoo will have a pH level in the acidic to neutral range, typically between 4.5 and 5.5, to avoid causing damage or disrupting the natural pH balance of the hair and scalp.

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Final answer:

A pH-balanced shampoo should have a pH between 4.5 and 5.5, contain mild acids or bases, and help to keep the hair and scalp's natural pH level balanced.

Explanation:Characteristics of a pH-balanced shampoo:pH is between 4.5 and 5.5Contains mild acids or bases to maintain the desired pH level Helps to keep the hair and scalp's natural pH level balanced

A pH-balanced shampoo is important because it prevents the scalp from becoming too dry or too oily. It ensures that the hair cuticle is closed, reducing frizz and improving shine. Using a pH-balanced shampoo can also help maintain the effectiveness of other hair products.

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What volume of air at room conditions (20c , 760 torr) would be required to combust a full lighter of butane

Answers

The amount of air required to combust a full lighter of butane can be calculated using the stoichiometry of the combustion reaction. The complete combustion of butane (C4H10) can be represented by the following equation:

C4H10 + 6O2 -> 4CO2 + 5H2O

From this equation, we can see that for every mole of butane combusted, 6 moles of oxygen are required. To determine the volume of air required, we need to know the concentration of oxygen in air.

Air is composed of approximately 21% oxygen and 79% nitrogen, and since the pressure of air is 760 torr, the partial pressure of oxygen is:

0.21 * 760 torr = 160 torr

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Changes in ______move matter from one state to another.
temperature
pressure
density
location

Answers

Answer:

temperature

Explanation:

differentiate between atoms and their ions on the basis of their stability.​

Answers

Answer:

The difference between an atom and an ion has to do with net electrical charge. An ion is a particle or collection of particles with a net positive or negative charge. ... A stable atom contains the same number of electrons as protons and no net charge. When electrons are added or removed, the stable atom becomes an ion.Apr 12, 2015

Explanation:

hope this helps ✌️

If you have 60 moles of HCl, what should the volume of solution be to make a 10 M solution?

Answers

Answer:10

Explanation:

Multiply the volume by the density to get the mass.

Divide the mass by the molar mass to get the number of moles.

Other Questions
ravi scored 42 runs in 7 overs and sunil scored 63 in 9 overs. who scored more runs per over in ratio....,....... pls send urgent ^ all of the following are characteristic of jewish art, except which? a. the art showed depictions of religious stories from the torah. b. artists combined strong outlines with flat colors. Findg(t)for the functiong(t)=9/t4g(t)= ___ Case B: Ospry, Inc., has working capital in the amount of $ 960,000. For each of the following transactions, determine whether working capital will increase, decrease, or remain the same.Paid accounts payable in the amount of $ 10,000. H2SO4(aq) + Pb(C2H3O2)2(aq) --> PbSO4(s) + 2 HC2H3O2(aq)Solutions of sulfuric acid and lead (II) acetate react to form solid lead (II) sulfate and a solution of acetic acid. If 18.6 g of sulfuric acid and 12.6 g of lead (II) acetate are mixed, calculate the number of grams of sulfuric acid, lead (II) acetate, lead (II) sulfate, and acetic acid present in the mixture after the reaction is complete.Which chemical is the limiting reactant? How many grams of sulfuric acid are leftover? gramsHow many grams of lead (II) acetate are leftover? gramsHow many grams of lead (II) sulfate are produced? gramsHow many grams of acetic acid are produced? grams STORIES OF USEFUL INVENTIONS, excerptBy S. E. Forman1911THE MATCHThere never was a time when the world was without fire, but there was a time when men did not know how to kindle fire; and after they learned how to kindle one, it was a long, long time before they learned how to kindle one easily. In these days we can kindle a fire without any trouble, because we can easily get a match; but we must remember that the match is one of the most wonderful things in the world, and that it took men thousands of years to learn how to make one. Let us learn the history of this familiar little object, the match.Fire was first given to man by nature itself. When a forest is set on fire by cinders from a neighboring volcano, or when a tree is set ablaze by a thunderbolt, we may say that nature strikes a match. In the early history of the world, nature had to kindle all the fires, for man by his own effort was unable to produce a spark. The first method, then, of getting fire for use was to light sticks of wood at a flame kindled by natureby a volcano, perhaps, or by a stroke of lightning. These firebrands were carried to the home and used in kindling the fires there. The fire secured in this way was carefully guarded and was kept burning as long as possible. But the flame, however faithfully watched, would sometimes be extinguished. A sudden gust of wind or a sudden shower would put it out. Then a new firebrand would have to be secured, and this often meant a long journey and a deal of trouble.In 1827, John Walker, a druggist in a small English town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. The druggist had discovered the first friction-chemical match, the kind we use to-day. It is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. Although Walker's match did not require the bottle of acid, nevertheless it was not a good one. It could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. In a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. The match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. It would ignite when rubbed on any dry surface, and there was no longer any sputtering. This was the phosphorus match, the match with which we are so familiar.Read the first sentence of the text:There never was a time when the world was without fire, but there was a time when men did not know how to kindle fire; and after they learned how to kindle one, it was a long, long time before they learned how to kindle one easily.What is the main purpose of this sentence in the essay? To describe the misery of early human existence To explain how early fires were started To suggest humans have an easier life than we once did To support the idea that matches really changed human life what is the solution of 6x=15 What mathematician's foundations can be found in Computer Aided Design software and what are these elements?. PLS HELP If a serve hits the net, what happens?Re-doDead BallOther teams pointPlay the ball Juan sells a boat that he bought 5 years ago. He sells it for 60% less than he originally paid for it. If the original cost is b, write an expression that shows how much he sells the boat for gatt, gats, and trips are three agreements that are part of the: a. north american free trade agreement. b. european union. c. world trade organization. d. general agreement on tariffs and trade. The following excerpt is: 7:21 (3:52)A. The Triumphal March from the opera AidaB. The River theme from The MoldauC. And With His Stripes from MessiahD. The Hallelujah Chorus by Handel played on the trumpetA. The Triumphal March from the opera Aida 1. Assume an investor purchased a six-month T-bill with a $10,000 par value for $9,840 and sold it ninety days later for $9,900. What is the yield. Starches are the first food particles to be broken down during the digestive process a. True b. False Did Andrew Jackson fully support states rights did he support the federal government at all? Arguments supporting development of oil exploration in the Arctic National Wildlife Refuge include all of the following EXCEPT: A. The infrastructure already in place at Prudhoe Bay can be used to process oil from the Refuge. B. Development of domestic oil would improve the balance of trade and lessen U.S. dependence on foreign oil. C. The Arctic National Wildlife Refuge is an extremely fragile ecosystem, in part because of its harsh climate. D. The Arctic National Wildlife Refuge, established in 1980, is a remote location seldom visited by tourists. D. There is a high probability of finding oil within the Refuge. I dont know how to do these problems Pls help me A player kicks a football from ground level with a velocity ofmagnitude 27.0 m/s at an angle of 30 above the horizontal.What is the horizontal distance the ball travels?(hint: d= 1/2 at^2) If A and B are any two events with P(A) = .8 and P(B|A) = .4, then the joint probability of A and B is: a. .32 b. .40 c. 1.20 d. .80 Describe tectonic plates and explain how they "float" on the Earth's surface (what do they float on and what causes theirmovement). (site 1)