Compounds

How many atoms of each element are in the chemical formula Ca(OH)2?

1 calcium, 2 oxygen, and 2 hydrogen

How many atoms of each element are in 4Na3PO4?

12 sodium, 4 phosphorus, 16 oxygen

How many atoms of nitrogen are in the chemical formula Ni(NO3)2?

2

How many atoms of each element are in the chemical formula P2O5?

2 phosphorus and 5 oxygen

There are___atoms of oxygen in the chemical formula 2Ca(ClO2)2.

8

Which statement correctly describes whether a compound is a pure substance?

A compound is a pure substance because its molecule cannot be broken down into simpler particles by physical means.

Which is the best description of a molecule?

A molecule of a compound is composed of at least two types of atoms.

There are several ways to model a compound. One type of model is shown. What is the chemical formula for the molecule modeled?

C6H12O2

Which of these is a compound?

CO2

Carl makes the table below to determine the number of atoms of each element in the chemical formula 4Ca(ClO3)2. What mistake did Carl make?

He did not multiply the chlorine and oxygen atoms by the coefficient 4.

What does the chemical formula CaCl2 show about the compound it represents?

It is made up of two elements.

In what way is Model A better than Model B?

Model A shows the three-dimensional shape of the molecule, but Model B does not.

Two models of the same compound are shown. In what way is Model B better than Model A?

Model B shows how the atoms in the molecule are connected, but Model A does not.

Elena makes the table below to determine the number of atoms of each element in the chemical formula 3(NH4)2SO4.

She should not have multiplied the sulfur atoms by the subscript 4.

Obi is trying to determine if a powdery, solid substance is an element or a compound. After recording some observations, he strongly heats a sample of the solid over a burner flame. After fifteen minutes, he turns off the flame and allows the sample to cool. He records his final observations in the data table.

The chemical reaction with acid changed, showing that the sample was broken down by heating. Therefore, the original substance is a compound.

"Na2SO3" represents sodium sulfite. What does the 4 mean in the formula 4Na2SO3?

There are four molecules of sodium sulfite.

The compound magnesium phosphate has the chemical formula Mg3(PO4)2. In this compound, phosphorous and oxygen act together as one charged particle, which is connected to magnesium, the other charged particle. What does the 2 mean in the formula 5Mg3(PO4)2?

There are two phosphate ions in a molecule of magnesium phosphate.

Which statements describe how chemical formulas, such as H2O, represent compounds? Check all that apply.

They show the elements that make up a compound. They show the types of atoms that make up a molecule. They show the number of each type of atom in a molecule.

There are several different models that represent compounds. One type of model is shown. What type of model is shown?

a ball-and-stick model

There are several different models that represent compounds. One type of model is shown. What type of model is shown?

a structural formula