Regents Chemistry Stoichiometry

The gram molecular mass of Ca₃(PO₄)₂ is

• 246 g
• 279 g
• 310 g
• 342g

What is the mass in grams of 5.90 mol C₈H_18?

• .0512 g
• 19.4 g
• 673 g
• 389 g

Tags

NGSS.HS-PS1-7

36.0 g of Be contains how many moles?

• 0.25 mol
• 4.0 mol
• 45 mol
• 320 mol

What is the percent composition by mass of magnesium in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%

• 27%

• 46%

• 53%

The students measured length during a science experiement, they got 12 cm. But the actual measurement was 14.25 cm. What was the percent error?

• 15.79%
• 18.75%
• 2.25%
• 18%

How many moles are in 3.01 x 10²² atoms of magnesium?

• 0.05 moles
• 1.81 x 10⁴⁶ moles
• 5.00 x 10²¹ moles
• 5 moles

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

• C₃H₆
• CH₂
• C₂H₄
• CH₃

What is the molecular formula if the empirical formula is C₂H₅ and the molecular molar mass is 58.14 g/mol?

• C₂H₅

• C₄H₁₀

• C₈H₁₅

• C₄H₈

What is the empirical formula if you have 88.80% copper and 11.20% oxygen?

• Cu₃O₈
• CuO₄
• Cu₂O
• Cu₄O₁₀

If 15.6 g of hydrate are heated and only 11.7 g of anhydrous salt remain, calculate the % of water lost.

• 25.9%
• 19.2%
• 37.9%
• 76.3%