Which of these is a compound?
O
CO2
O2
Co
How many atoms of each element are in the chemical formula P2O5?
2 phosphorus and 5 oxygen
5 phosphorus and 2 oxygen
1 phosphorus and 5 oxygen
2 phosphorus and 1 oxygen
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 elements in magnesium phosphate.
There are two molecules of magnesium phosphate.
There are two magnesium ions in a molecule of magnesium phosphate.
There are two phosphate ions in a molecule of magnesium phosphate.
How many atoms of each element are in 4Na3PO4?
3 sodium, 1 phosphorus, 4 oxygen
4 sodium, 4 phosphorus, 4 oxygen
12 sodium, 1 phosphorus, 4 oxygen
12 sodium, 4 phosphorus, 16 oxygenTwo models of the same compound are shown.
A top line labeled Model A saying C subscript 2 H subscript 4 O subscript 2. A bottom image with 2 C's connected by 1 black line. The left C has 3 H's connected to it by 1 black line each and the right C has 2 Os attached to it, the top O by two black lines and the bottom O by 1 black line. The bottom O also has an H attached to it by 1 black line.
In what way is Model B better than Model A?
Model B shows the types of elements in the compound, but Model A does not.
Model B shows the three-dimensional shape of the molecule, but Model A does not.
Model B shows how the atoms in the molecule are connected, but Model A does not.
Model B shows the number of atoms of each element in the molecule, but Model A does not.
How many atoms of oxygen in the chemical formula 2Ca(ClO2)2?
2
4
6
8
There are several different models that represent compounds. One type of model is shown.
How many atoms of nitrogen are in the chemical formula Ni(NO3)2?
2
1
6
3
A large black sphere connected to 4 small blue spheres by 4 grey sticks.
What type of model is shown?
a structural formula
a chemical formula
a space-filling model
a ball-and-stick model
Which statement describes how chemical formulas, such as H2O, represent compounds?
They show the types of molecules that make up an atom.
They show the elements that make up a compound.
They show the three-dimensional shape of a molecule.
They show the types of bonds that exist between elements.
Which is the best description of a molecule?
A molecule of an element is composed of at least two types of atoms.
A molecule of a compound is composed of only one atom.
A molecule of a compound is composed of at least two atoms.
A molecule of an element is composed of exactly two types of atoms.
