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3 years ago

Can someone help me understand what 1b is asking and how to answer it?

Chemistry

1 answer:

icang [17]3 years ago

5 0

The question is basically asking what is happening to the energy (that is in the form of heat) when it is being absorbed by an object. The energy being absorbed from the heat source is being turned into kinetic energy. This can be explained by temperature change. As you add more heat to an object, the temperature rises. Since temperature is the average kinetic energy of all of the molecules in an object, we can say that as temperature rises so does the kinetic energy of the molecules in the object. Due to the fact that heat is causing the temperature to increase, we can say that the energy from the heat is being turned into kinetic energy.

I hope this helps. Let me know in the comments if anything is unclear.

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I NEED HELP ASAP, WILL MARK BRAINLEST!

Andre45 [30]

Answer:

1. 90%

2. 217.4 g O₂

3. 95.0%

4. Trial 2 ratios

Explanation:

Original: SiCl₄ + O₂ → SiO₂ + Cl₂

Balanced: SiCl₄ + O₂ → SiO₂ + 2Cl₂

Trial SiCl₄ O₂ SiO₂

1 120 g 240 g 38.2 g

2 75 g 50 g 25.2 g

Percentage yield for trial 1

We need to get actual yield (38.2 g) and theoretical yield, in grams.

Mass to moles:

molar mass SiCl₄: 28.09 + 4(35.45) = 169.9 g/mol

120 g SiCl₄ x 1 mol/169.9 g = .706 mol SiCl₄

Moles to moles:

For each mole SiCl₄, we have one mol SiO₂ based on the balanced rxn.

.706 mol SiCl₄ = .706 mol SiO₂

Moles to mass:

molar mass SiO₂: 28.09 + 2(16.00) = 60.09 g/mol

.706 mol SiO₂ x 60.09g/mol = 42.44 g SiO₂

Theoretical yield:

actual/theoretical x 100

38.2 / 42.44 = .900 = 90.0% yield

Leftover reactant for trial 1

We know oxygen is the excess reactant.

Mass to moles:

molar mass O₂ = 32.00 g/mol

240 g O₂ x 1 mol/32.00 g = 7.5 mol O₂

We used .706 mol SiO₂, so we also used .706 mol O₂.

7.5 - .706 = 6.8 moles left over

Moles to mass:

6.8 mol O₂ x 32.00g/mol = 217.4 g O₂

Percentage yield for trial 2

Mass to moles:

molar mass SiCl₄: 169.9 g/mol

75 g SiCl₄ x 1 mol/169.9 g = .441 mol SiCl₄

Moles to moles:

For each mole SiCl₄, we have one mol SiO₂ based on the balanced rxn.

.441 mol SiCl₄ = .441 mol SiO₂

Moles to mass:

molar mass SiO₂: 60.09 g/mol

.441 mol SiO₂ x 60.09g/mol = 26.5 g SiO₂

Theoretical yield:

actual/theoretical x 100

25.2 / 26.5 = .950 = 95.0% yield

Because the percentage yield of trial 2 is higher than that of trial 1, we know that the ratio of reactants in trial 2 is more efficient! We got a result closer to our theoretical yield.

6 0

4 years ago

What is the molar mass of barium hydroxide

maksim [4K]

Answer:

171.34 g/mol

Explanation:

Ba molar mass = 137.328 g/mol

O molar mass = 15.999 g/mol * 2 = 31.9980 g/mol

H molar mass = 1.008 g/mol * 2 = 2.0160 g/mol

137.328 + 31.9980 + 2.0160 = 171.3420 = 171.34 g/mol

4 0

3 years ago

Coefficients in a chemical equation express _____ between molecules or compounds.

Pavel [41]

Coefficients in a chemical equation express RATIOS between molecules or compounds.

In chemical equations, coefficient refers to those numerical numbers that are usually written at the front of elements' chemical symbols in order to balance the equations. Coefficients tell us the number of a particular element that must react with a specific number of another element in order for certain amount of chemical products to be produced; that is, it provide information about the reaction ratio of reactants and products. For instance, look at this chemical equation: N2 + 3H2 = 2NH3

In the equation given above, the coefficient of N2 is 1, the coefficient of H2 is 3 and the coefficient of NH3 is 2. What this equation is essentially telling us is that, in order to produce two molecules of ammonia, one molecule of nitrogen must react with three molecules of hydrogen. Thus, the equation gives the ratios between the product and the reactants.

3 0

3 years ago

Read 2 more answers

A new penny has a mass of 2.49 grams and occupies 0.349 cm cubed. If pure copper has a density of 8.96 g/cm cubed, is the new pe

lys-0071 [83]

Answer: The new penny is not pure copper

Explanation:

Density $\rho$ is defined as a relation between the mass $m$ and the volume $V$ :

$\rho=\frac{m}{V}$

Now, we are told the density of pure copper is:

$\rho_{copper}=8.96 g/cm^{3}$

And we are given the mass and volume of the new penny, with which we can calculate its density:

$\rho_{penny}=\frac{m_{penny}}{V_{penny}}=\frac{2.49 g}{0.349 cm^{3}}$

$\rho_{penny}=7.13 g/cm^{3}$ As we can see the density of this penny is not equal to the density of pure copper, hence the new penny is not pure copper.

8 0

4 years ago

What is the difference between atoms and molecules?

Westkost [7]

Hi there,

In a molecule, atoms are bonded together by single, double, or triple bonds. An atom has a nucleus surrounded by electrons. ... So another difference between atoms and molecules is that when similar atoms combine together in varying numbers,molecules of different properties can be formed.

hope you understand

3 0

4 years ago