Chemistry

Question 1

What is the atomic number of an element?

Answer 1

The atomic number is the number of protons in the nucleus of an atom.

Question 2

True or False: Isotopes of an element have the same number of protons but different numbers of neutrons?

Answer 2

True

Question 3

Fill in the blank: The formula for calculating the number of neutrons in an atom is ______.

Answer 3

mass number - atomic number

Question 4

What is the relative atomic mass of an element?

Answer 4

The weighted average mass of an atom of an element compared to 1/12th of the mass of a carbon-12 atom.

Question 5

What is the main difference between ionic and covalent bonding?

Answer 5

Ionic bonding involves the transfer of electrons, while covalent bonding involves the sharing of electrons.

Question 6

Which particle has a negative charge?

Answer 6

Electron

Question 7

What is the pH scale used for?

Answer 7

The pH scale is used to measure the acidity or alkalinity of a solution.

Question 8

What is the chemical formula for water?

Answer 8

H2O

Question 9

True or False: Metals tend to lose electrons to form positive ions.

Answer 9

True

Question 10

What do you call a substance that speeds up a chemical reaction without being consumed?

Answer 10

Catalyst

Question 11

What is the law of conservation of mass?

Answer 11

Mass is neither created nor destroyed in a chemical reaction.

Question 12

What is the general equation for photosynthesis?

Answer 12

6CO2 + 6H2O → C6H12O6 + 6O2

Question 13

Fill in the blank: The process of a solid turning into a gas without becoming a liquid is called ______.

Answer 13

sublimation

Question 14

What is a mole in chemistry?

Answer 14

A mole is a quantity that contains 6.022 x 10^23 particles of a substance.

Question 15

Which gas is produced when an acid reacts with a carbonate?

Answer 15

Carbon dioxide (CO2)

Question 16

What is the main component of natural gas?

Answer 16

Methane (CH4)

Question 17

True or False: All acids have a pH less than 7.

Answer 17

True

Question 18

What is an exothermic reaction?

Answer 18

A reaction that releases energy in the form of heat.

Question 19

What is the process of separating a liquid mixture based on different boiling points called?

Answer 19

Distillation

Question 20

Fill in the blank: The symbol for sodium is ______.

Answer 20

Na

Question 21

What is the main purpose of a titration?

Answer 21

To determine the concentration of a solution.

Question 22

What is the formula for calculating the concentration of a solution?

Answer 22

Concentration = mass of solute / volume of solution

Question 23

True or False: The periodic table is arranged by increasing atomic mass.

Answer 23

False

Question 24

What type of bond is formed when two nonmetals share electrons?

Answer 24

Covalent bond

Question 25

What does the term 'saturation' refer to in chemistry?

Answer 25

A solution that cannot dissolve any more solute at a given temperature.

Question 26

Fill in the blank: The chemical formula for table salt is ______.

Answer 26

NaCl

Question 27

What is the main characteristic of alkali metals?

Answer 27

They are highly reactive and have one electron in their outer shell.

Question 28

What is the main use of sulfuric acid?

Answer 28

It is commonly used in car batteries and in the manufacture of fertilizers.

Question 29

True or False: Noble gases are very reactive due to their full outer electron shells.

Answer 29

False

Question 30

What does the term 'oxidation' refer to?

Answer 30

The loss of electrons from a substance during a reaction.

Question 31

What are the products of the electrolysis of water?

Answer 31

Hydrogen and oxygen gases.

Question 32

Fill in the blank: The pH of a neutral solution is ______.

Answer 32

7

Question 33

What is the process by which plants absorb water through their roots called?

Answer 33

Osmosis

Question 34

What type of reaction is photosynthesis?

Answer 34

Endothermic reaction

Question 35

What is the main gas found in the Earth's atmosphere?

Answer 35

Nitrogen (N2)

Question 36

What is the empirical formula for glucose, C6H12O6?

Answer 36

CH2O

Question 37

True or False: A catalyst increases the activation energy of a reaction.

Answer 37

False

Question 38

What are transition metals known for?

Answer 38

They have variable oxidation states and form colored compounds.

Question 39

What does the term 'hydration' refer to in chemistry?

Answer 39

The process of combining a substance with water.

Question 40

Fill in the blank: The chemical symbol for iron is ______.

Answer 40

Fe

Question 41

What is a reduction reaction?

Answer 41

The gain of electrons by a substance during a reaction.

Question 42

What is the main role of enzymes in biological systems?

Answer 42

To act as catalysts for biochemical reactions.

Question 43

True or False: Increasing temperature generally increases the rate of a chemical reaction.

Answer 43

True

Question 44

What is the difference between saturated and unsaturated hydrocarbons?

Answer 44

Saturated hydrocarbons contain only single bonds, while unsaturated hydrocarbons contain at least one double or triple bond.

Question 45

Fill in the blank: The process of converting a liquid to a gas is called ______.

Answer 45

evaporation