Chemistry

Question 1

What is the difference between an element and a pure substance?

Answer 1

An element is made of only one kind of atom, but a substance is made of only one kind of molecule.

Question 2

Which has more energy: gas or solid?

Answer 2

Gas

Question 3

Which has more movement: gas or solid?

Answer 3

Gas

Question 4

Which has the highest density: gas, solid, or liquid?

Answer 4

Solid

Question 5

What is the difference between an atom and a molecule?

Answer 5

Molecules are made of atoms; atoms are only one element, molecule can be more than one

Question 6

What is the difference between a homogenous and heterogenous mixture?

Answer 6

Homogenous: completely mixed, can’t be separated
Heterogenous: cannot be completely mixed

Question 7

How is a law different from a theory?

Answer 7

Law: used to summarize an observation
Theory: an observation about the natural world

Question 8

Is density a physical or chemical property?

Answer 8

Physical

Question 9

Is PH level a chemical or physical property?

Answer 9

Chemical

Question 10

Is baking a cake a chemical or physical change?

Answer 10

Chemical

Question 11

Is melting butter a physical or chemical change?

Answer 11

Physical

Question 12

What does a Bohr diagram resemble?

Answer 12

A solar system

Question 13

In an Electron Cloud model, how do electrons act?

Answer 13

Like waves, not particles

Question 14

What is an element?

Answer 14

A pure substance determined by the number of protons in its nucleus

Question 15

What is a proton?

Answer 15

Positively charged subatomic particle

Question 16

What is a neutron?

Answer 16

Neutrally charged subatomic particle

Question 17

What is a electron?

Answer 17

Negatively charged subatomic particle

Question 18

What is the atomic number?

Answer 18

Number of protons in the atom

Question 19

What is the atomic mass?

Answer 19

Number of both protons and neutrons together

Question 20

What is the charge of an atom with more protons than electrons?

Answer 20

Positive

Question 21

What is the charge of an atom with the same amount of protons and electrons?

Answer 21

Neutral/none

Question 22

Who created the periodic table?

Answer 22

Mendeleev

Question 23

Which are the most and least reactive groups in the periodic table?

Answer 23

Most: Alkali metals
Least: Noble gases

Question 24

What is another name for a molecular compound?

Answer 24

Covalent compound

Question 25

What is the difference between the elements found in ionic and molecular compounds:

Answer 25

Ionic: contains metals Molecular: only non-metals

Question 26

True or false: two of the same elements can bond to make a covalent compound.

Answer 26

True (example: O2)

Question 27

Which kind of compound uses prefixes in the names?

Answer 27

Covalent

Question 28

True or false: covalent compounds use roman numerals to tell how many of each element there is.

Answer 28

False

Question 29

When you combine two elements together, what kind of reaction is happening?

Answer 29

Formation

Question 30

When you split a compound into separate elements, what kind of reaction is happening?

Answer 30

Decomposition

Question 31

In a chemical equation, which side of the arrow are the reactants on?

Answer 31

The left side

Question 32

Which kind of chemical reaction releases heat and energy?

Answer 32

Exothermic

Question 33

True or false: baking bread is an endothermic reaction.

Answer 33

True

Question 34

What are the four ways to increase the rate of a chemical reaction?

Answer 34

Stirring, higher temperature, reactant concentration, increasing surface area

Question 35

What does a catalyst do?

Answer 35

Speeds up the rate of reaction

Question 36

What are catalysts called that are involved in biological processes?

Answer 36

Enzymes

Question 37

True or false: a cation is negatively charged.

Answer 37

False