SLO Demonstrate use of dimensional analysis converting from one unit to another through the mole Directions: Answer the following questions. Set-up all problems using the factor-label method of dimensional analysis and show all your work and units. 1. What volume would be occupied by 9.45 x 10²⁴ molecules of CO₂ gas at STP? 2. How many calcium atoms would be in a 100 gram sample of calcium metal? How many grams are in 5.6 x 10²³ atoms of Zinc? 3. Calculate the number of molecules in 4.56-g of Pb (NO₃) ₂.

Question

Chemistry

Ainsley Bird

2 June, 00:43

SLO Demonstrate use of dimensional analysis converting from one unit to another through the mole Directions: Answer the following questions. Set-up all problems using the factor-label method of dimensional analysis and show all your work and units. 1. What volume would be occupied by 9.45 x 10²⁴ molecules of CO₂ gas at STP? 2. How many calcium atoms would be in a 100 gram sample of calcium metal? How many grams are in 5.6 x 10²³ atoms of Zinc? 3. Calculate the number of molecules in 4.56-g of Pb (NO₃) ₂.

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Answers (1)

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Joey Roth · Answer 1

1. 351.62L

2. 15.05 * 10^23 molecules

3. 54.6g

4. 8.29 * 10^21 molecules

Explanation:

1. First we will need to calculate the number of moles present in such number of molecules. We know that one mole contains 6.02 * 10^23 molecules. Hence to calculate the number of moles in 9.45 * 10^24 carbon iv oxide Miley, we simply divide. And that is (9.45 * 10^24) / (6.02 * 10^23) = 15.7 moles

At s. t. p, a mole of a gas will occupy a volume of 22. L. Hence 15.7 moles will occupy a volume of 15.7 * 22.4 = 351.62L

2. We first need to calculate the number of moles of calcium metal present in 100g. To do this we simply divide the mass by the atomic mass of calcium. The atomic mass of calcium is 40 amu. The number of moles is thus 100/40 = 2.5 moles

One mole contains 6.02 * 10^23 number of molecules. Hence 2.5 moles will contain 2.5 * 6.02 * 10^23 = 15.05 * 10^23 molecules

3. Firstly we need to calculate the number of moles contained in those number of molecules. What we simply need do is to divide by 6.02 * 10^23

Since the power of 10 is same, we simply divide 5.06 by 6.02 = 0.84 moles

To get the mass, we simply multiply by the atomic mass of zinc. The atomic mass of zinc is 65a. m. u

The mass is thus 0.84 * 65 = 54.6g

4. Firstly we will need to calculate the number of moles here. To do this we divide the mass by the molar mass. The molar mass of lead nitrate is 331g/mol

The number of moles is thus 4.56/331 = 0.014 moles

1 mole contains 6.02 * 10^23 molecules, then 0.014 moles will contain 0.014 * 6.02 * 10^23 molecules = 8.29 * 10^21 molecules