Regular Chemistry QPA3 review 2020

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇
• C₂H₄O₂ and C₆H₁₂O₆
• C₃H₆O₃ and C₂H₆O₂
• CH₄ and C₂H₆

An empirical formula:

• is a formula that calculates the coefficients of a compound in a balanced equation.
• is the simplest whole-number ratio of moles of elements in the compound.

What is the empirical formula of the following molecular formula:  C₃H₆

• C₃H₆
• CH₂
• C₂H₄
• CH₃

Which one is empirical?

• H₂O₂
• C₂H₆O₁₂
• CaCl₂
• N₂O₈

Find the percent composition of CaCl₂?

• Ca: 36.11%; Cl: 63.88%

• Ca: 53.12%; Cl: 100%

• Ca: 36.11%; Cl: 83.56%

• Ca: 46.11%; Cl: 63.88%

What percent of Zn₃(PO₄)₂ is zinc?

• 33.15%

• 16.04%

• 50.80%

• 19.68%

How many water molecules are in 5.2 moles of water?

• 6.02 x 10²³
• 5.2
• 3.1 x 10²⁴
• 8.638 x 10^-24

Tags

NGSS.HS-PS1-7

How many molecules are in 2.5 mol of NaCl?

• 1.50 x10²² molecules

• 1.50 molecules

• 4.15 molecules

• 1.51 x10²⁴ molecules

What is a possible molecular formula for CH₂?

• C₅H₈

• CH₄

• C₃H₆

• C₃H₄

What is a possible molecular formula for XY₄?

• X₂Y₈

• XY₂

• X₅Y₇

• X₃Y₅