Atoms and Molecules Review

How many Hydrogen are in 4H₂O?

• 6

• 8

• 2

• 4

Answer explanation

In 4H2O, each water molecule (H2O) contains 2 hydrogen atoms. Therefore, 4H2O has 4 x 2 = 8 hydrogen atoms. Thus, the correct answer is 8.

Tags

NGSS.MS-PS1-1

How many Oxygen are in H₂O?

• 1

• 2

• 0

• 4

Answer explanation

In H2O, there are 2 hydrogen atoms and 1 oxygen atom. Therefore, the correct answer is 1, as there is 1 oxygen in each molecule of water.

Tags

NGSS.MS-PS1-1

2H₂ + O₂ ----> 2H₂O What is the product?

• ------>

• 2H₂O

• 2H₂+ O₂

Answer explanation

The reaction shows that 2 molecules of hydrogen (H2) react with 1 molecule of oxygen (O2) to produce 2 molecules of water (H2O). Therefore, the correct product is 2H2O.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

2H₂ + O₂ --------> 2H₂O What  are the reactants?

• ----->

• 2H₂O

• 2H₂ +O₂

Answer explanation

The reactants in the reaction are the substances that undergo change. In this case, 2H2 (hydrogen) and O2 (oxygen) are the reactants, which combine to form 2H2O (water). Therefore, the correct choice is 2H2 + O2.

Tags

NGSS.MS-PS1-5

How many O's are in Al₂(SO₄)₃

• 4

• 12

• 7

• 24

Answer explanation

In Al₂(SO₄)₃, there are 3 sulfate (SO₄) groups. Each sulfate has 4 oxygen atoms, totaling 3 x 4 = 12 oxygen atoms. Therefore, the correct answer is 12.

Tags

NGSS.MS-PS1-1

Number of H in 3(NH₄)₂CrO₄

• 4

• 2

• 8

• 24

Answer explanation

In 3(NH₄)₂CrO₄, each NH₄ has 4 H atoms. There are 2 NH₄ groups per formula unit, giving 8 H atoms. Since there are 3 formula units, the total is 3 x 8 = 24 H atoms. Thus, the correct answer is 24.

Tags

NGSS.MS-PS1-1

How many atoms are there TOTAL in:
H₂SO₄

• 6

• 5

• 7

• 3

Answer explanation

H2SO4 consists of 2 hydrogen (H) atoms, 1 sulfur (S) atom, and 4 oxygen (O) atoms. Adding them together: 2 + 1 + 4 = 7. Therefore, the total number of atoms in H2SO4 is 7.

Tags

NGSS.MS-PS1-1

How many Sodium (Na) are in 6NaCl?

• 1

• 12

• 6

Answer explanation

In the compound 6NaCl, there are 6 sodium (Na) atoms because the coefficient '6' indicates that there are 6 units of NaCl, and each NaCl contains 1 sodium atom. Therefore, 6NaCl contains 6 sodium atoms.

Tags

NGSS.MS-PS1-1

A subscript is the small number below a(n) ________ that tells the number of _______ of that element.

• element symbol; atoms

• atom; element symbol

• subscript; protons

• compound; elements

Answer explanation

A subscript is a small number written below the element symbol in a chemical formula. It indicates the number of atoms of that element present in the compound, making "element symbol; atoms" the correct choice.

Tags

NGSS.MS-PS1-1

How many atoms of Oxygen are in Fe(NO₃)₃ ?

• 6

• 3

• 9

• 1

Answer explanation

In Fe(NO3)3, there are 3 nitrate (NO3) groups. Each nitrate contains 3 oxygen atoms, so 3 x 3 = 9 oxygen atoms in total. Therefore, the correct answer is 9.

Tags

NGSS.MS-PS1-1