Chemistry - General Questions

Question 1

Which chemical equation below is correctly balanced?

Accepted Answer

CH4 + 2O2 → 2H2O + CO2

Question 2

Law of conservation of mass: the mass of the products must be ____ the mass of the reactants.

Accepted Answer

equal to

Question 3

Which formula below represents a molecule?

Accepted Answer

CO2

Question 4

Theobromine,a chemical in chocolate, has the formula C7H8N4O2.What elements and how many atoms?

Accepted Answer

7 carbon, 8 hydrogen, 4 nitrogen, 2 oxygen

Question 5

Using the periodic table, what is the atomic number of barium?

Accepted Answer

56

Question 6

If an atom loses an electron, it has a ______________ charge.

Accepted Answer

positive

Question 7

What element is shown in the atomic model below?

Accepted Answer

magnesium

Question 8

A row of elements on the periodic table is called a ______________.

Accepted Answer

period

Question 9

If an atom gains an electron, it has a ______________ charge.

Accepted Answer

negative

Question 10

Which particle is NOT found in the nucleus of an atom?

Accepted Answer

electron

Question 11

Look at the element key for tin. How many neutrons in a tin atom?

Accepted Answer

69

Question 12

What is special about elements that are in the same group of the periodic table?

Accepted Answer

They have similar chemical properties.

Question 13

How many valence electrons in the atom below?

Accepted Answer

4

Questions 13