Grams Moles Conversions

How do we get mass from moles?

• multiply by avogadro's number

• multiply by molar mass

• divide by avogadro's number

• divide by molar mass

Calculate the number of atoms in 0.0340 g Zn.

• 5.200 x 10^-4 atoms Zn

• 3.130 x 10²³ atoms Zn

• 3.130 x 10²⁰ atoms Zn

• 1 atom Zn

Tags

NGSS.HS-PS1-7

How many moles are in 19.82 g Mg?

• 1.23 mol Mg

• 481.70 mol Mg

• 1.00 mol Mg

• 0.82 mol Mg

How many grams are in 1.2 x 10²⁴ atoms of C?

• 29.34 grams

• 23.94 grams

• 6.02 grams

• 1.21 grams

What is the molar mass of PbSO₄

• 303.3 g/mol

• 294.7g/mol

• 163.8g/mol

• 372g/mol

How many grams are in 1.2 moles of Neon?

• 0.05 grams

• 16.6 grams

• 21.2 grams

• 24 grams

Use the given the chemical equation to answer the following question: 2C₂H₆ + O₂ → 4CO₂ + 6H₂O What does the number 4 represent for the formula unit 4CO2 ?

• The number 4 represents the coefficient, which is also equal to the number of grams of the formula unit above.

• The number 4 represents the subscript, which is also equal to the number of moles of the formula unit above.

• The number 4 represents the coefficient, which is also equal to the number of moles of the formula unit above.

• The number 4 represents the subscript, which is also equal to the number of grams of the formula unit above.

How many grams of NH₃ would result in 8 moles of NH_3. What does the the number 8 do to the molar mass of the compound?

• The number 8 is added to the molar mass to give 25 g/mol.

• The number 8 multiplies the molar mass by 8 to give 136 g/mol.

• The number 8 divides the molar mass by 8 to give 2.13 g/mol.

• The number 8 does not change the molar mass of the compound.

Which of the following methods should be used in order to calculate the molar mass of magnesium hydroxide?

• Add the masses of two moles Mg to the mass of one mole OH

• Add the total protons and neutrons.

• Add the masses of one mole Mg to the mass of one mole OH

• Add the masses of one mole Mg to the masses of two moles of OH.

A student calculated the number of moles of methane (CH4) present in a 100g sample of a gaseous mixture. If the student determined that there’s 0.6 moles of methane present in the sample, what is the percent composition of methane in the sample?

• .096%

• 9.6%

• .9%

• 90%