Stoichiometry - Section 1 Exam

What is the relationship between moles and molecules?

• 1 mole = 6.022 x 10^23 molecules

• 1 mole = mass of a molecule in amu

• 6.022 x 10^23 moles = 1 molecule

• molecules x atoms x moles = 6.022 x 10^23

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NGSS.HS-PS1-7

How many moles are in 36 grams of water (H₂O)?

How many moles are in 180 grams of NaCl?

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NGSS.HS-PS1-7

How many molecules are in 1 mole of nitrogen gas (N₂)?

• 6.022 x 10²³

• 28

• 2

• 1.2044 x 10²⁴

Convert 2.5 moles of CO₂ to grams.

What is the molar mass of boron nitrate, B(NO₃)₃?

Two different molecular formulas​​ (a)   have the same empirical formula. The empirical formula subscripts​ (b)   be reduced. To solve the molecular from the empirical, a chemist must know the​ (c)   of the molecular formula. And it is​ (d)   the empirical and molecular formulas are identical.

• can
• cannot
• molar mass
• possible
• not possible
• molarity
• percent composition

Calculate the mass of 0.25 moles of NaCl.

A compound’s empirical formula is CH, and its molar mass is 78 g/mol. What is its molecular formula?

(a)  

Determine the empirical formula of a compound with 85.7% carbon and 14.3% hydrogen.

(a)