at the molecular level: a. create a question a researcher would ask at this level b. give an example of an experiment that could be done to answer questions at this level

Answer:

2g/mL

Explanation:

Density = m/V

Density = 40g/20mL = 2g/mL

Answer:

Explanation:

The balanced chemical equation is Cl2 + 2KBr → 2KCl + Br2. The amount of bromine is calculated as follows:

11.0 g KBr (1mol KBr/119.002g KBr * 1mol Br2/2mol KBr * 159.808g Br2/1mol Br2= 7.39 g Br2.)

Answer:

D. genetic modification

Explanation:

Out of the given examples, genetic modification represents the use of modern biotechnology. Genetic modification involves the direct manipulation of an organism’s DNA using biotechnology techniques to produce desired traits or characteristics. This is a relatively recent development in biotechnology and is used in various fields such as agriculture, medicine, and environmental science.

Bread making and cheese making are traditional food production techniques that have been used for centuries and do not necessarily involve modern biotechnology. Selective breeding is also a traditional technique that has been used for thousands of years to develop desired traits in plants and animals by choosing which individuals are allowed to reproduce.

Answer:

These are called cis-but-2-ene (where the groups are on the same side) or trans-but-2-ene (where they are on opposite sides). Cis-but-2-ene is also known as (Z)-but-2-ene; trans-but-2-ene is also known as (E)-but-2-ene. For an explanation of the two ways of naming these two compounds, follow the link in the box below.

Explanation:

false, the rusting of iron can be prevented by painting, oiling, greasing or varnishing its surface.

Answer:

0.77mol/Kg.

Explanation:

The following data were obtained from the question:

Mass of NaCl = 4.5g

Mass of water = 100g.

Molality =...?

Next, we shall determine the number of mole in 4.5g of NaCl. This can be obtained as follow:

Mass of NaCl = 4g.

Molar mass of NaCl = 23 + 35.5 = 58.5g/mol

Number of mole NaCl =..?

Mole = Mass /Molar Mass

Number of mole of NaCl = 4.5/58.5

Number of mole of NaCl = 0.077 mole.

Next, we shall convert 100g of water to kilograms. This is illustrated below:

1000g = 1kg

Therefore, 100g = 100/1000 = 0.1Kg.

Finally, we can determine the molality of the solution as follow:

Molality is simply defined as the mole of solute per unit kilogram of solvent (water). Mathematically, it is represented as:

Molarity = mole of solute / kg of solvent

Mole of solute, NaCl = 0.077 mole

Kg of solvent = 0.1kg

Molality = 0.077mol/0.1kg

Molality = 0.77mol/Kg

The molarity of the solution is 0.77mol/Kg.

Since

Mass of NaCl = 4.5g

Mass of water = 100g.

Here,

Mass of NaCl = 4g.

Molar mass of NaCl = 23 + 35.5 = 58.5g/mol

Now

Mole = Mass /Molar Mass

= 4.5/58.5

= 0.077 mole.

Now

1000g = 1kg

So,

100g = 100/1000 = 0.1Kg.

Now

Molarity = mole of solute / kg of solvent

Mole of solute, NaCl = 0.077 mole

Kg of solvent = 0.1kg

So,

Molality = 0.077mol/0.1kg

= 0.77mol/Kg

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The mass of water produced if the percent yield of the reaction is 72% is 16.2g.

Mass of acetylene = 40.0 grams

Mass of oxygen = 40.0 grams

Percent yield of the reaction = 72%

The balanced chemical equation is : 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g)

From the balanced chemical equation, it is clear that 2 moles of acetylene reacts with 5 moles of oxygen to form 2 moles of water.

To find out limiting reagent

Moles of acetylene = Given mass of acetylene / molar mass of acetylene

                                 = 40.0 g / 26 g/mol = 1.54 moles

Moles of oxygen = Given mass of oxygen / molar mass of oxygen

                                = 40.0 g / 32 g/mol = 1.25 moles

The limiting reactant is oxygen because its number of moles is less than acetylene. Oxygen will react with 1.25 moles of acetylene present and form CO2 and H2O.

According to the balanced equation, the stoichiometric ratio of C2H2 to H2O is 2:2, meaning that for every 2 moles of C2H2, 2 moles of H2O are produced.

Since the stoichiometry is 1:1, the moles of water produced will be the same as the moles of acetylene used.

The number of moles of H2O produced 1.25 moles.

The mass of H2O produced = Number of moles of H2O × Molar mass of H2O

Mass of H2O produced = 1.25 × 18 = 22.5 g

Given percent yield = 72%

The actual yield can be calculated as follows;

Percent yield = Actual yield / Theoretical yield × 100

72% = Actual yield / 22.5 g × 100

Actual yield = 22.5 g× 72 / 100 =16.2 g

Thus, the mass of water produced if the percent yield of the reaction is 72% is 16.2g.

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Answer:

c

Explanation:

because the ion are Mobil which mean they are free not combined and carry a charge but when they are combined/ fixed in position they can't carry a charge so therefore can't conduct electricity  :)

Answer:

D.HI

Explanation:

because this is the most different

In Newton's 2nd law, written in terms of force, mass and acceleration, m stands for the mass in the original Newton's work, i.e. the quantity of the substance which makes up a material body.

Have a great day/ night hope this helped out <33

Answer: lithosphere

Explanation:

continents are a part of lithosphere.

core is a structure of earth

Diatoms are single-celled algae that have a silica (silicate) shell called a frustule.

Diatoms are photosynthetic organisms and are known for their intricate and diverse shapes. Diatoms are commonly found in freshwater and marine environments and play a significant role in the global carbon cycle.

Micrite is a fine-grained carbonate sedimentary rock composed of tiny carbonate particles. It forms through the precipitation and accumulation of carbonate minerals, such as calcite or aragonite, in marine environments. In the case of chalk, which is primarily composed of microscopic fragments of calcium carbonate from marine organisms, recrystallization can occur at the ocean bottom under specific conditions, leading to the formation of micrites.

Therefore, it's important to note that chert, marble, and quartzite are not the typical products of recrystallization of chalk at the ocean bottom.

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Answer:

answer is 2

Explanation:

just did the quiz

Explosive materials need to be handled carefully and stored appropriately to avoid the possibility of initial combustion.   The following are some of the precautions to take when handling explosive materials: Avoid any type of friction, impact, or shock, whether small or large, when handling explosive materials.

Keep the containers of explosive materials tightly sealed to prevent the infiltration of moisture or contaminants. Store the explosives in a cool, dry, and well-ventilated environment, keeping them away from any heat sources or flammable materials. Keep the explosives away from direct sunlight to prevent the heat from building up and causing an explosion.

In conclusion, explosive materials should be handled and stored with care to prevent initial combustion, which may lead to an explosion. Explosives should be stored in a dry, cool, and well-ventilated area, and containers should be kept tightly sealed to prevent moisture or contaminants from entering. Explosives should also be kept away from any heat sources or flammable materials.

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Answer:

Hope this helps!

Explanation:

To calculate the pOH of a solution you need to know the concentration of the hydroxide ion in moles per liter (molarity). The pOH is then calculated using the expression: pOH = - log [OH-] Example: What is the pOH of a solution that has a hydroxide ion concentration of 4.82 x 10-5 M?

To find the pOH, simply subtract the pH from 14. In order to calculate the pOH, take the negative log of the hydroxide ion concentration.

The poH equation and how it should be determined from pH should be explained below.

To determine the pOH of the solution here first we know the concentration of the hydroxide ion in terms of moles per liter (molarity). The pOH should be then calculated by applying the following expression.

pOH = - log [OH-]

Now for determining the pOH here we considered the negative log of the  hydroxide ion concentration.

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Answer: Carbon cycle wouldn't be able to create rock formation. Respiration, consumption, combustion (such as fossil burning) are all part of the carbon cycle. They would all be possible without internal energy. Except rock formation.

Explanation:

Almost all the commonly using cleaning products in homes and offices are nothing but they are the disinfectants. The chemical products that destroy all bacteria, fungi, and viruses on surfaces are known as Disinfectants.

A disinfectant is defined as the antimicrobial agent which is usually applied on the surface of some objects in order to destroy the microorganisms residing on it. Chlorine bleach is the most powerful disinfectant.

Any substance which acts on non-living objects to kill germs, like viruses, bacteria, etc. is called the disinfectant.

Thus the correct option is B.

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Approximately 222.4 grams of oxygen reacted in the combustion process. To determine the amount of oxygen that reacted, we can use the balanced chemical equation for the combustion of hydrogen:

2H₂ + O₂ → 2H₂O

From the equation, we can see that 1 mole of oxygen reacts with 2 moles of hydrogen to produce 2 moles of water.

First, we need to convert the given masses of hydrogen and water into moles using their molar masses:

Molar mass of hydrogen (H₂) = 2 g/mol

Molar mass of water (H₂O) = 18 g/mol

Mass of hydrogen in moles = 27.8 g / 2 g/mol = 13.9 mol

Mass of water in moles = 249 g / 18 g/mol = 13.8 mol

Since the stoichiometry of the reaction tells us that 2 moles of hydrogen react with 1 mole of oxygen, we can calculate the moles of oxygen consumed as:

Moles of oxygen consumed = 13.9 mol / 2 = 6.95 mol

Finally, we can convert the moles of oxygen to grams using its molar mass:

Molar mass of oxygen (O₂) = 32 g/mol

Mass of oxygen consumed = 6.95 mol × 32 g/mol = 222.4 g

Therefore, approximately 222.4 grams of oxygen reacted in the combustion process.

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4.56g excess reactant is left over when 17.0 g of potassium hydroxide (KOH) reacts with 20.0 g of iron (III) nitrate (Fe(NO₃)₃)

Reactants are raw materials that react with one another and form products.

Here given balanced reaction is

2KOH + Fe(NO₃)₂ → Fe(OH)₂ + 2KNO₃

Then we have to calculated the masses of KOH and Fe(NO₃)₂ from the balanced reaction

Molar mass of KOH = 39+16+1 = 56g/mol

Mass of KOH = 2×56 = 112g

And the molar mass of Fe(NO₃)₂ = 56+2[14+(16×3)]

= 56+2[14 + 48)]

= 56+2[62]

= 56+124

= 180g/mol

Then from the balanced equation

112g of KOH and 180g/mol of  Fe(NO₃)₂

Then the 17 g of KOH = 17×180/112g

= 27.32 g of Fe(NO₃)₂

Then for 20.0 g of iron (III) nitrate

Therefore Xg of KOH = 112×20/180

Xg of KOH = 12.44g

Thus 12.44g of KOH reacted

Therefore we have determine the leftover mass of the excess reactant

Mass of KOH leftover = ?

Mass of KOH leftover = (Mass of KOH given) – (Mass of KOH that reacted)

Mass of KOH leftover = 17 - 12.44g

Mass of KOH leftover = 4.56g

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Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

\(n = \frac{N}{L} \\\)

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question

N = 9.02 × 10^25 molecules of HCI

We have

\(n = \frac{9.02 \times {10}^{25} }{6.02 \times {10}^{23} } \\ = 149.83388704...\)

We have the final answer as

Hope this helps you

Answer:

A) A longer stamen could ensure that an insect brushes against an anther and picks up pollen.

Explanation:

The stamen will provide easier access to the pollen.

Hope this helps :)

Answer:

Arsenic

Explanation:

according to my school

Based on the properties of elements in the periodic table arsenic (As)  is the weakest conductor of electricity.

In the periodic table, all the 118 known elements are arranged in order depending on their properties.

Certain trends can be observed among elements in the periodic table. One of them is the trend of electrical conductivity.

Electrical conductivity decreases across the period as metallic properties decrease.

As such arsenic (As) is the least metallic element in the list and is the weakest conductor of electricity.

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Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Therefore, because of the evaporation of upper surface of liquid, volume decreases.

Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.

Matter is anything that is made up of atoms. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.

The volume of Substance 1 change from 3 liters of liquid to just over 0.50 liters after it was boiled and then cooled because on heating the molecules on the upper surface of liquid evaporates.

Therefore, because of the evaporation of upper surface of liquid, volume decreases.

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The value of Gibbs free energy is 143876.5 joules

The maximum amount of work that can be accomplished by a thermodynamically closed system at constant temperature and pressure can be calculated using the Gibbs free energy (also known as Gibbs energy; symbol: Δ G). Additionally, it offers a prerequisite for any processes like chemical reactions that might take place in such circumstances.

The maximum amount of non-expansion work that can be taken from a closed system (one that may exchange heat and work with its surroundings but not matter) at fixed temperature and pressure is known as the Gibbs free energy change (ΔG =ΔH - TΔS), measured in joules in SI. This maximum is only possible with a fully reversible method. Under these circumstances, when a system changes reversibly from an initial state to a final state, the reduction in Gibbs free energy is equal to the work performed by the system on its surroundings less the work of the pressure forces.

ΔH=-158 kj = enthalpy change

T=655k = temperature

ΔS=-219.9 j/k = entropy

ΔG =ΔH - TΔS

     =-158 -(655 x -219.9)

    = -158 -(-144034.5)

    =143876.5 joules

so, the value of Gibbs free energy is 143876.5 joules

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So,

There's an equation that we could use in order to find frequency, and it is the next one:

This equation tells us that the energy of the photon is equal to the product of the Plank constant (h), which is 6.626*10^-34 J.s, and the frequency.

In this problem, we know the value of E and the value of h, so we need to solve for v:

Therefore, the correct answer option is A.

Answer:

the particles start to move about, staying close to their neighboring particles, then move more freely.

Answer:

I have for Decompostion

Explanation:

A decomposition reaction occurs when one reactant breaks down into two or more products. It can be represented by the general equation: AB → A + B. In this equation, AB represents the reactant that begins the reaction, and A and B represent the products of the reaction

Answer:

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Because water is polar and oil is nonpolar, their molecules are not attracted to each other. ... Because water molecules are polar, they interact with the sodium and chloride ions. In general, polar solvents dissolve polar solutes, and nonpolar solvents dissolve nonpolar solutes.

Explanation:

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