Molar Mass, Mole Conversion, and Percent Composition

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 conversion factor should be used to solve the following, "How many moles in 28 grams of CO₂?"

• 1 mol = 22.4 L

• 1 mol = 44.0 g

• 1 mol = 6.02x10²³ atoms

• more than one

Find the percent composition of hydrogen in (NH₄)₂S.

• 11.8%

• 41.1%

• 47.1%

How many molecules are in 9.44 moles of Aluminum chloride?

• 5.68 molec AlCl₃

• 5.68x10²⁴ molec AlCl₃

• 0.705 molec AlCl₃

• 1.25x10²³ molec AlCl₃

Tags

NGSS.HS-PS1-7

Which conversion factor should be used for the following question " How many molecules are there in 4.00 moles of glucose, C₆H₁₂O₆? 

• mole = 78.12 g

• mole = 22.4 L 

• mol = 6.02x 10²³ particles 

• more than one

How many molecules are in 2.5 mol of NaCl?

• x10²⁴ molecules

• molecules

• molecules

• x10²⁴ molecules

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 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.

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.

Tags

NGSS.HS-PS1-7