Mole Unit Test Review

What is the mass of 0.89 mol of CaCl₂?

• 110 grams

• 0.0080 grams

• 99 grams

• none of the choices

Tags

NGSS.HS-PS1-7

What is the molar mass of Ca(NO₃)₂?

• 148.096 g

• 164.086 g

• 102.055 g

• 70.084 g

How many moles are in 74 g of KCl

• 0.99 mole

• 0.014 mole

• 11 moles

• 0.14 mole

Find the percent composition of Cu₂S?

• %Cu= 67.987 %S= 32.013
• %Cu= 79.854   %S= 20.145
• %Cu= 35.946   %S= 64.054

What is the percent by mass of fluorine in CaF₂

(molar mass = 78 g/mol)?

• 24%

• 49%

• 51%

• 65%

In which compound is the percent composition by mass of Cl equal to 42%?

• HClO (molar mass = 52 g/mol)

• HClO₂ (molar mass = 68 g/mol)

• HClO₃ (molar mass = 84 g/mol)

• HClO₄ (molar mass = 100 g/mol)

In a percent hydrate lab, a student measured out 5.7 grams of the hydrate and heated it until all of the water evaporated. After heating, the student measured the annhydrous salt remaining and determined the mass to be 4.8 grams. What was the percent of water lost from the hydrate sample?
 $\%\ H_2O\ =\ \frac{mass\ of\ water\ lost}{mass\ of\ hydrate}\ X\ 100\$  

• 118%

• 84.2%

• 15.8%

• 50%

Reflect on the percent water in a hydrate lab. If your sample was still blue after you heated it, how would your calculation of the percent water in the hydrate be influenced?

• The calculated percent water lost would be lower than the theoretical value.

• The calculated percent water lost would be higher than the theoretical value.

• This would not have an impact on the calculated percent water lost.

• Cannot be determined

A chemical formula with the lowest whole number ratio of elements in a compound is called

• Molecular Formula

• Covalent Formula

• Empirical Formula

• Formula Unit

What is the molecular formula if the empirical formula is CH₂O and the subscripts are multiplied by 6.

• CH₂O

• C₂H₄O₂

• C₄H₈O₄

• C₆H₁₂O₆