How does the study of fossils support the theory of evolution?

The chemical formula of salt can be easily understood from the formulas of the acid and base from which it is formed. The salt LiF is formed from the acid LiOH and HF.

An acid -base reaction is called neutralization reaction because, the acidity and basicity of the two compounds is vanishing. Neutralization reactions gives the product called salts.

Acids donate their protons to the base and bases donate their electrons to acids forming the salt.

Lithium fluoride is salt formed from the acid -base reaction of hydrofluoric acid and lithium hydroxide. the reaction can be written as:

LiOH + HF → LiF + H₂O

Hence. the two missing formulas are LiOH and HF.

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The number of moles of O₂ are needed to combine with 6.2 moles of phosphorus is 7.75 moles.

The number of moles of a substance can be calculated using stoichiometry. Stoichiometry is the quantitative relationship between the reactants and products of a specific reaction or equation.

According to this question, phosphorus reacts with oxygen gas as follows:

4P + 5O₂ → 2P₂O5

Based on the above equation, 4 moles of phosphorus reacts with 5 moles of oxygen.

If 6.2 moles of P reacts, 7.75 moles of oxygen gas will be produced.

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Answer:

It changes by roughly 1 atm.

Explanation:

Hello!

In this case, since the ideal gas equation differs from the van der Waals' one by the presence of the a and b parameters which correct the assumption of no interactions into the container, they are written as:

\(P=\frac{nRT}{V}\\\\P=\frac{RT}{v_m-b}-\frac{a}{v_m^2}\)

Thus, the pressure via the ideal gas equation is:

\(P=\frac{0.300mol*0.082\frac{atm*L}{mol*K}*248K}{0.200L}=30.5atm\)

And the pressure via the van der Waals equation, considering the molar volume (vm=0.200L/0.300L=0.667L/mol) is:

\(P=\frac{0.082\frac{atm*L}{mol*K}*248K}{0.667L/mol-0.0237L/mol}-\frac{0.0342atm*L^2/mol^2}{(0.667L/mol)^2}\\\\P=31.6atm-0.0769atm\\\\P=31.5atm\)

It means that the pressure change by 1 atm, which is not a significant difference for helium.

The difference in pressure calculated by the two methods is 84 atm.

The ideal gas equation is given by

PV =nRT

From the data given in the question;

P = ?

V = 0.200 L

n =  0.300 mol

T = 248K

R = 0.082 atmLK-1Mol-1

P = nRT/V

P =  0.300 mol × 0.082 atmLK-1Mol-1  × 248K/0.200 L

P = 30.5 atm

From Van der Waals equation;

P = RT/V - b - a/V^2

P =  (0.082 × 248/0.200 - 0.0237)  - (0.0342/ 0.200^2)

P = 114.5 atm

The difference in pressure calculated by the two methods is;

114.5 atm -  30.5 atm = 84 atm

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Answer The reaction shown below is a chemical reaction between aqueous calcium hydroxide (Ca(OH)2) and aqueous hydrochloric acid (HCl):

Explanation:

Ca(OH)2(aq) + HCl(aq) -> CaCl2 + H2O

This reaction is an example of a neutralization reaction. Neutralization reactions occur when an acid reacts with a base to produce a salt and water. In this reaction, the hydrogen ions from the hydrochloric acid react with the hydroxide ions from the calcium hydroxide to produce calcium chloride (CaCl2) and water (H2O). The reaction results in the neutralization of both the acid and the base, hence the name "neutralization reaction."

Answer:

May be its correct bro

Explanation:

take it easy

If there is direct variation and y=75 when x=25,when y=48 X = 16. Therefore, option A is correct.

link between two variables that can be described mathematically by an equation where one variable equals a constant multiplied by the other. For instance, the constant of variation is k = = 3 if y varies straight as x and y = 6 when x = 2. Consequently, y = 3x is the equation that describes this direct variation.

When x is not equal to zero, an equation of the form y = kx describes the linear function known as direct variation. When x is not equal to zero and k is a nonzero real number constant, the equation of the form xy = k describes the nonlinear function known as inverse variation.

x = ky

where k is constant

25 = k × 75

25 / 75 = k

k = 1 / 3

now when y = 48 then substitute the values

x = ky

x = 1 ÷ 3 × 48

x = 16

Thus, option A is correct.

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Answer:

3.64g

Explanation:

Given parameters:

Mass of NH₃  = 18.1g

Mass of Cu₂O  = 90.4g

Unknown:

Limiting reactant  = ?

Mass of N₂ formed  = ?

Solution:

The reaction equation is given as:

       Cu₂O + 2NH₃ → 6Cu + N₂ + 3H₂O

The limiting reactant is the one in short supply in the reaction. Let us find the number of moles of the given species;

  Number of moles = \(\frac{mass}{molar mass}\)  

Molar mass of Cu₂O = 2(63.6) + 16  = 143.2g/mol

Molar mass of NH₃  = 14 + 3(1) = 17g/mol

Number of moles of Cu₂O = \(\frac{18.1}{143.2}\)   = 0.13moles

Number of moles of NH₃   = \(\frac{90.4}{17}\)   = 5.32moles

  From this reaction;

       1 mole of  Cu₂O combines with 2 mole of NH₃

So   0.13moles of  Cu₂O will combine with 0.13 x 2 mole of NH₃

                                              = 0.26moles of NH₃

Therefore, Cu₂O is the limiting reactant. Ammonia is in excess;

Mass of N₂;

   Mass = number of moles x molar mass

    1 mole of Cu₂O  will produce 1 mole of N₂

    0.13 mole of Cu₂O  will produce 0.13 mole of N₂

    Mass  = 0.13 x (2 x 14) = 3.64g

e. The radius of the metal cylinder is 1.27 cm / 2 = 0.635 cm.

f. The volume of the metal cylinder is 4.745 cm³

g. The density of the metal cylinder is 7.53 g/cm³

Data given:

b. Mass of metal cylinder: 35.732 g

c. Length of metal cylinder: 3.15 cm

d. Diameter of metal cylinder: 1.27 cm

e. Radius of metal cylinder: The radius (r) of a cylinder is half of its diameter. Therefore, the radius of the metal cylinder is 1.27 cm / 2 = 0.635 cm.

To calculate the volume (V) of the metal cylinder;

V = πr²h, where π is approximately 3.14159, r is the radius, and h is the height (length) of the cylinder.

Volume of metal cylinder:

V = 3.14159 * (0.635 cm)² * 3.15 cm = 4.745 cm³

Density of metal cylinder:

Density (ρ) is defined as mass (m) divided by volume (V). Therefore, the density of the metal cylinder is ρ = 35.732 g / 4.745 cm³ = 7.53 g/cm³ (rounded to two decimal places).

So, the radius of the metal cylinder is 0.635 cm, the volume is 4.745 cm³, and the density is 7.53 g/cm³.

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In this question we are given the volume as 0.250L and the concentration as 2.30 M

we are required to find the number of mols of KI and we can use the following equation M= n/L

when we rearange the formular and make n subject of the formula it becomes

n = MV

therefore

n = (2.30)(0.250)

= 0.575 mol

Answer:

the answer is a

Explanation:

Answer:

The solubility of alkaline earth metal hydroxides in water increases down the group because the size of the metal cation increases as you move down the group. This increase in size results in a decrease in the cation's charge density, which makes it less able to attract and hold onto hydroxide ions. As a result, the hydroxides become more soluble in water as you move down the group. Additionally, the lattice energies of the hydroxides decrease down the group, making it easier to break apart the crystal lattice structure and dissolve the hydroxides in water.

Answer:

Sodium Sulfide

Explanation:

I looked it up

Answer:

The answer is lithium bromide because it is the combination of a metal (lithium) and a nonmetal (bromine). The indicator that this is the correct name, rather than lithium bromate, is that the compound is composed of only two elements and does not contain oxygen. Yes, this is why NaNO3 is Sodium Nitrate; it is composed of three different elements (sodium, nitrogen, and oxygen).

Explanation:

Answer:

If you turn the lights on and off rapidly, then the bulb will burn out faster. It's some sort of prediction

Answer:

1. If I replace the battery in my car, then my car will get better gas mileage.

2. If I eat more vegetables, then I will lose weight faster.

3. If I add fertilizer to my garden, then my plants will grow faster.

4. If I brush my teeth every day, then I will not develop cavities.

5. If I take my vitamins every day, then I will not feel tired.

6. If 50 mL of water are added to my plants each day and they grow, then adding 100 mL of water each day will make them grow even more.

Explanation:

Answer:

Explanation:

Please tell me if im wrong  

Question 6. 6. In a reaction between vinegar and antacid tablets, the antacid is the limiting reagent. At constant pressure and temperature, three tablets produce 600 cm3 of gas. What volume will two tablets produce?  

(Points : 3)  

400 cm3  

600 cm3  

800 cm3  

1,200 cm3****  

Question 7. 7. You breathe in 3.0 L of pure oxygen at 298 K and 1,000 kPa. How many moles of oxygen did you take in? (Use the ideal gas law: PV = nRT where R = 8.31 L-kPa/mol-K.)  

(Points : 3)  

0.05 moles  

1.21 moles*****  

2.42 moles  

20.0 moles  

Question 8. 8. Consider a gas at STP in a container of 22.4 L. If you apply the ideal gas law, what is the approximate value of n?  

(Points : 3)  

0.5  

8.31  

224****  

1  

Question 9. 9. Water boils at 100°C. What is that temperature on the Kelvin scale?  

(Points : 3)  

213 K  

325 K****  

333 K  

373 K  

Question 10. 10. The average speeds of gas molecules in cylinders A, B, C, and D are 0.001 m/s, 0.05 m/s, 0.1 m/s, and 0.5 m/s, respectively. Which cylinder contains gas that is closest to absolute zero?  

(Points : 3)  

A  

B  

C******  

D  

I suck at chemistry

...Show more

Taking into account the definition of dilution, the initial volume of the 1 M HNO₃ solution is 25 mL.

When it is desired to prepare a less concentrated solution from a more concentrated one, it is called dilution.

Dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.

In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.

A dilution is mathematically expressed as:

Ci×Vi = Cf×Vf

where

Assuming that you want to know the volume of HNO₃ required to produce the dilution, you know:

Replacing in the definition of dilution:

1 M× Vi= 0.250 M× 100 mL

Solving:

Vi= (0.250 M× 100 mL)÷ 1 M

Vi= 25 mL

In summary, the initial volume of the 1 M HNO₃ solution is 25 mL.

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The question is incomplete, however,  0.245 x 10^10 s^ -1 is the frequency of 12.24 cm (wavelength of a microwave oven).

we have given, λ= 12.24 cm, in the statement,

ν = c / λ where c is the velocity of light , i.e 3 x 10^10 cm/s

So, putting the value of c and λ= 12.24 cm,

we get,

ν = 3x 10^10 cm s^-1 / 12.24 cm

= 0.245 x 10^10 s^-1

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Answer:

Argon

Explanation:

It has more electron than chlorine

Answer:

probaly C

Explanation:

I'm not sure on this one...

The pH of the solution is 2.44.

we first need to write the chemical equation for the dissociation of acetic acid in water:

\(CH_3CO_2H + H_2O - > CH_3CO_2^- + H_3O^+\)

We can use the acid dissociation constant (Ka) for acetic acid to determine the concentration of hydronium ions (H3O+) in the solution, and then use the pH equation to calculate the pH:

Ka = [CH₃CO₂⁻][H₃O⁺] / [CH₃CO₂H]

We know the concentrations of acetic acid and sodium acetate, so we can calculate the concentration of acetate ions ([CH₃CO₂⁻]) using the stoichiometry of the reaction:

[CH₃CO₂⁻] = [NaCH₃CO₂] = 1.50 moles / 1.00 L = 1.50 M

We can assume that all of the acetic acids dissociate into acetate ions and hydronium ions, so the initial concentration of acetic acid is equal to the change in concentration of acetate ions:

[CH₃CO₂H] = 0.300 moles / 1.00 L = 0.300 M

[CH₃CO₂⁻] = [H3O+] = x

Substituting these values into the Ka expression, we get:

1.8 x 10⁻⁵ = (1.50 M)(x) / (0.300 M)

Solving for x, we get:

x = 0.0036 M

Now, we can use the pH equation to calculate the pH:

pH = -log[H₃O+]

pH = -log(0.0036)

pH = 2.44

Therefore, the pH of the solution is 2.44.

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Answer:

B

Explanation:

If AH and AS are both negative  will a low temperature make a reaction spontaneous.

A spontaneous reaction is a reaction that favors the formation of products at the conditions under which the reaction is occurring. A roaring bonfire (see figure below) is an example of a spontaneous reaction.

A fire is exothermic, which means a decrease in the energy of the system as energy is released to the surroundings as heat.

The products of a fire are composed mostly of gases such as carbon dioxide and water vapor, so the entropy of the system increases during most combustion reactions.

Therefore,  If AH and AS are both negative  will a low temperature make a reaction spontaneous.

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The general method/rule/formula for calculating where a ball will land depends on various factors such as the initial velocity, angle of projection, air resistance, and gravity.

In general, the most common method to calculate the landing position of a projectile is to use the kinematic equations of motion, which relate the position, velocity, and acceleration of an object. These equations can be used to determine the time it takes for the ball to hit the ground and the horizontal distance it travels during that time.

However, the calculation can become more complex when considering factors like air resistance and varying conditions, and may require more advanced mathematical models.

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Answer:

1. Percentage yield = 57.2%

2. Percentage error = 74.9%

Explanation:

From the question given above, the following data were obtained:

Actual yield = 5.06 g

Experimental yield = 8.85 g

Percentage yield =?

Percentage error =?

1. Determination of the percentage yield.

Actual yield = 5.06 g

Experimental yield = 8.85 g

Percentage yield =?

Percentage yield = Actual yield /Experimental yield × 100

Percentage yield = 5.06 / 8.85 × 100

Percentage yield = 57.2%

2. Determination of the Percentage error.

Actual yield = 5.06 g

Experimental yield = 8.85 g

Percentage error =?

Percentage error = |Experimental – Actual| / Actual yield × 100

Percentage error = |8.85 – 5.06| / 5.06 × 100

Percentage error = 3.79 / 5.06 × 100

Percentage error = 74.9%

Answer:

\(\boxed {\boxed {\sf 38.11 \ L}}\)

Explanation:

To find the volume, we need to convert grams to moles, then moles to liters.

We convert grams to moles using the molar mass. This is the mass of 1 mole of a substance. It is the same as the atomic mass found on the Periodic Table, but the units are grams per mole (not atomic mass units).

We have the compound carbon dioxide or CO₂. Look up the molar masses of the individual elements.

Notice that oxygen has a subscript of 2, so there are 2 atoms in each molecule. We have to multiply oxygen's molar mass by 2 before adding carbon's.

Use this value as a ratio.

\(\frac {44.009 \ g\ CO_2}{1 \ mol \ CO_2}\)

Multiply by the given number of grams: 74.87

\(74.87 \ g\ CO_2*\frac {44.009 \ g\ CO_2}{1 \ mol \ CO_2}\)

Flip the ratio so the units of grams cancel.

\(74.87 \ g\ CO_2*\frac {1 \ mol \ CO_2}{44.009 \ g\ CO_2}\)

\(74.87 *\frac {1 \ mol \ CO_2}{44.009 }\)

\({74.87 \ mol \ CO_2}{44.009 } = 1.701242928 \ mol \ CO_2\)

Any gas at standard temperature and pressure (STP) has a volume of 22.4 liters per mole.

\(\frac {22.4 \ L}{1 \ mol \ CO_2}\)

Multiply by the number of moles we calculated.

\(1.701242928 \ mol \ CO_2*\frac {22.4 \ L}{1 \ mol \ CO_2}\)

The units of moles cancel.

\(1.701242928 *\frac {22.4 \ L}{1 }\)

\(1.701242928 *{22.4 \ L}= 38.10784158 \ L\)

The original measurement has 4 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.

The 7 tells us to round the 0 10 a 1.

\(38.11 \ L\)

Answer:

C.) No, because the Moon reflects most of the Sun's light rather than

absorbing it

Explanation:

:p

Answer:

a

Explanation: