8.5D Chemical formulas

How many different elements are in K₂SO₄?

• 1

• 3

• 4

• 7

A group of students creates a table to use while completing an investigation with these chemicals.

Which formulas above represent a molecule with 6 atoms?

• C₃H₈O and NaHCO₃

• MgSO₄ and NaHCO₃

• NH₄OH and C₃H₈O

• C₂H₄O₂ and MgSO₄

A group of students discusses how to determine the number of atoms in each substance.

Student 1 states that the coefficient determines the number of atoms in each substance.

Student 2 says the subscripts determine the number of atoms in each substance and student 3 thinks the chemical symbols determine the number of atoms in each substance.

Which student is correct?

• Student 1

• Student 1 and 2

• Student 2

• Student 2 and 3

How many oxygen atoms are in the following chemical formula?

Al₂(CO₃)₃

• 3

• 6

• 9

• 18

What is the correct method for determining the total number of hydrogen atoms in the following chemical formula?

(NH₄)₂CrO₇

• Multiply the subscript outside the parentheses by the subscript after the hydrogen

• Use the subscript after the hydrogen to determine the total number of hydrogen atoms in the substance

• Add the subscript outside the parentheses to the subscript after the hydrogen

• Subtract the subscript outside the parentheses form the subscript after the hydrogen

What is the best description of this molecule of caffeine?

C₈H₁₀N₄O₂

• Eight atoms of carbon, ten atoms of hydrogen, and two atoms of oxygen

• Eight atoms of carbon, ten atoms of hydrogen, four atoms of nitrogen, and two atoms of oxygen

• Eight atoms of carbon, ten atoms of hydrogen, two atoms of nitrogen, and four atoms of oxygen

• Eight atoms of carbon, ten atoms of hydrogen, and six atoms of oxygen

According to the table, which chemical formula correctly represents the atoms in zinc phosphate?

• Zn₃P(O₄)₂

• Zn₃(PO₄)₂

• Zn₈P₂O₃

• Zn₃(PO₂)₄

How many different elements are part of one molecule of C₁₀H₇Cl₂OP?

• 19

• 20

• 21

• None of the above

Which statement is a valid conclusion about the substance diagrams below?

• The chemical formula for all three substances is different

• The chemical formula for substance 1 and 2 are the same, but the chemical formula for substance 3 is different

• The chemical formulas for substances 1 and 3 are the same, but the chemical formula for substance 2 is different.

• All three substances have the same chemical formula.

What information best completes the diagram?

• Number of compounds

• Located in front of the chemical symbols

• Number of molecules

• Located behind the chemical symbols