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How many particles are in a mole?

• 602
• 602 million
• 602 moles
• THIS IS THE ANSWER 6.02 x 10²³

What is the percent by mass of oxygen in MgO?

• 20%
• 40%
• 50%
• 60%

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

• 20%
• 27%
• 46%
• 53%

What percentage of the total atomic mass of magnesium bromide (MgBr₂) is composed of magnesium?

• 13%

• 43%

• 63%

• 87%

Tags

NGSS.MS-PS1-1

Find the percentage composition of Mg in Mg₃(PO₄)₂.

• 27.48% Mg

• 43.11% Mg

• 16.00% Mg

• 12.63% Mg

Determine the empirical formula of a compound with a molar mass of 78 g/mol and the following percent composition: 85.7% carbon and 14.3% hydrogen.

• The empirical formula is CH4

• The empirical formula is C3H3

• The empirical formula is CH3

• The empirical formula is CH2

Calculate the empirical formula of a compound with 20% magnesium, 26.7% phosphorus, and 53.3% oxygen.

• Mg2P3O7

• MgPO4

• MgP2O5

• Mg3P2O8

Calculate the empirical formula of a compound with 15% calcium, 20% nitrogen, and 65% oxygen.

• CaNO3

• CaNO2

• Ca2N2O6

• Ca2NO6

What is the empirical formula of a compound with 25% iron and 75% oxygen?

• FeO2

• Fe2O3

• FeO

• Fe3O4

Tags

NGSS.MS-PS1-1

Calculate the empirical formula of a compound with 30.4% potassium, 35.5% sulfur, and 34.1% oxygen.

• K2S2O7

• K2O3S6

• KSO3

• K2SO4