Percentage Composition Lab

What is the general formula for the computation of percentage composition of the given element?

• % mass of element = mass of element in the compound divided by mass of the compound times 100

• % mass of element = mass of element in the compound divided by mass of the compound

• % mass of element = mass of element in the compound divided by 100

• % mass of element = mass of element in the compound

Which of the following refers to molecular formulas?

• Are the formulas showing the type of atoms and number of each atom connected in the molecule.

• Are the simplest form of formulas that we can write for a molecule.

• A simple molecules like crystalline ionic compounds.

• Composed of two or more elements

Tags

NGSS.MS-PS1-1

What is the percent by mass of magnesium in MgO?

• 20%

• 40%

• 50%

• 60%

What is the percent by mass of chlorine in NaCl?

• 39%

• 61%

• 35%

• 35%

What is the percent by mass of fluorine in CaF₂ (gram-formula mass = 78 g/mol)?

• 24%

• 49%

• 49%

• 65%

What is the percent by mass of calcium in CaF₂ (gram-formula mass = 78 g/mol)?

• 24%

• 49%

• 51%

• 65%

Find the percent composition of Cu₂S?

• %Cu= 67.987 %S= 32.013

• %Cu= 79.854 %S= 20.145

• %Cu= 35.946 %S= 64.054

Tags

NGSS.HS-PS1-7

What is the percent composition of Benzene, C₆H₆?

• C = 50%

  H = 50%

• C = 85.7 %

  H = 14.3%

• C = 92.2%

  H = 7.8%

• C = 71.9%

  H = 28.1%

Which element in the compound potassium cyanide, KCN, has a percent composition of 60.97%?

• K

• C

• N

• None

What is the mass of one mole of aluminum chloride (remember to determine the correct formula first)?

• 62.435g

• 116.399g

• 133.341g

• 97.888g

Tags

NGSS.MS-PS1-1