Chemistry Midterm Review

How many molecules are in 2.5 mol of NaCl?

• 1.50 x10²⁴ molecules

• 1.50 molecules

• 4.15 molecules

• 1.51 x10²⁴ molecules

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

Tags

NGSS.HS-PS1-7

What is the percent composition by mass of sulfur (S) in the compound MgSO₄?

• 20.22%

• 19.85%

• 26.64%

• 28.64%

Determine the mass of 4.20 moles of C₆H₁₂

• 354 g

• 84 g

• 337 g

• 421 g

What is the molar mass of PbSO₄

• 303.3 g/mol
• 294.7g/mol
• 163.8g/mol
• 372g/mol

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%

When reacting Na with Cl₂, we calculated that the theoretical yield should be 12.5 grams. Our actual yield was 13.0 grams. What is the percent yield?

• 100%
• 104%
• 96%
• 1.04

Tags

NGSS.HS-PS1-7

CH₄ + 2O₂ → CO₂ + 2H₂O

24 grams of CH₄ was added to the above reaction. Calculate the theoretical yield of CO₂.

• 66 grams CO2

• 132 grams CO2

• 33 grams CO2

• 8.72 grams CO2

Tags

NGSS.HS-PS1-7

For the reaction represented by the equation Cl₂ + 2KBr → Br₂ + 2KCl, how many grams of potassium chloride (KCl) can be produced from 356 grams potassium bromide (KBr)?

• 749 g

• 223 g

• 479 g

• 814 g

Tags

NGSS.HS-PS1-7

Water and Kool-Aid are mixed together. Hot water, coffee and sugar are mixed together. Which substance is the solvent in both?

• Water
• Coffee
• Kool-aid
• Sugar