Third Quarter Practice Exam

What is the coefficient of O2 when the following equation is fully balanced with the smallest whole numbers?

H₂ + O₂ --> H₂O

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-5

When the following equation is correctly balanced using the smallest whole numbers, the coefficient of the water is ______.

Na(s) + H₂O(l) → NaOH(aq) + H₂(g)

• 1

• 2

• 3

• 4

What is the molar mass of CuSO₄ * 7H₂O?

• 160 g/mol

• 178 g/mol

• 286 g/mol

• 250 g/mol

What is the molar mass of Ca₃(PO₄)₂?

• 246 g/mol

• 279 g/mol

• 310 g/mol

• 342 g/mol

The total number of sodium atoms in 26.0 grams of sodium is __________.

• 3.01 x 10²⁴

• 6.81 x 10²³

• 1.20 x 10²⁴

• 2.40 x 10²⁴

Which quantity is equivalent to 39 grams of LiF?

• 1.5 mole

• 2.0 moles

• 0.50 mole

• .9 moles

What is the percent by mass of nitrogen in NH₃ (formula mass=17.0)?

• 5.9%

• 17.6%

• 21.4%

• 82.4%

A compound contains 40% calcium, 12% carbon, and 48% oxygen by mass. What is the empirical formula of this compound?

• CaCO₃

• Ca₂C₂O₆

• CaC₃O₆

• CaCO₂

A compound has an empirical formula CH2 and a molecular mass of 42. Its molecular formula is __________.

• C2H4

• C3H6

• C4H8

• C5H10

Using the equation below, identify the type of reaction it represents.

• Combustion

• Single-replacement

• Double-replacement

• Decomposition

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2