Open ended Stochiometry Quiz

How many moles are equal to 1.20 x 10^24 atoms of sulfur?

1.20 x 10²⁴ atoms of S x​ (a)  

​ (b)  

• 1 mol S
• 6.02 x 10^23 atoms S

How many atoms are equal to 1.5 moles of helium?

Tags

NGSS.HS-PS1-7

How many moles are equal to 89.23 g of calcium oxide, CaO?

Tags

NGSS.HS-PS1-7

How many moles are equal to 145 g of zinc nitrate, Zn(NO3)2?

145 g Zn(NO3)2 x ​ (a)   =

​ ​ (b)  

• 1 mol Zn(NO3)2
• 189.36 g  Zn(NO3)2

Tags

NGSS.HS-PS1-7

How many molecules are in 13.5 g of sulfur dioxide, SO2?

​ (a)   x ​ (b)   x ​ (c)  

​ (d)   1 mol SO2

• 13.5 g SO2
• 1 mol SO2
• 6.022 x 10^23 molecules
• 64.066 g SO2

What is the mass of 2.23 x 10^23 atoms of sulfur?

​ (a)   x ​ (b)   x​ (c)  

​ (d)   1 mo

• 2.23 x 10^23 atoms S
• 1 mol S
• 32.06 g S
• 6.022 x 10^23 atoms

Tags

NGSS.HS-PS1-7

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

• SO
• SO2
• SO3
• SO4

Answer explanation

When you are given %'s and asked for the formula, you need moles!

1) write the %'s as grams (here 40.05 g S and 59.95 g O)

2) use the molar masses from the Per. Tab. to convert grams -> moles.

3) if your moles are not whole numbers, you should either double all of the answers (if one of them ends in 0.5) OR divide all of the answers by the smallest answer.

** Remember, you are looking for whole number mole ratios to make a formula!

Use the following equation 2 GaCl3 + 3 F2 --> 2 GaF3 + 3 Cl2

How many atoms of fluoride would be produced from 78.9 grams of Gallium Chloride?

​ ​ ​ (a)   x ​ (b)   x ​ (c)   x​ (d)  

​ (e)   2 mol GaCl3. 1 mol F2

• 78.9 g GaCl3
• 1 mol GaCl3
• 3 mol F2
• 6.022 x 1023 atoms F2
• 176.073 g GaCl3

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7