Kemi - bra begrepp att kunna

Question 1

What is the basic unit of matter?

Answer 1

Atom

Question 2

True or False: A molecule is made up of two or more atoms bonded together.

Answer 2

True

Question 3

Fill in the blank: The _____ is the center of an atom.

Answer 3

nucleus

Question 4

What are the three main subatomic particles?

Answer 4

Protons, neutrons, and electrons

Question 5

Which particle has a positive charge?

Answer 5

Proton

Question 6

What is the term for a substance made of only one type of atom?

Answer 6

Element

Question 7

What is the periodic table?

Answer 7

A table that organizes all known elements by their atomic number and properties.

Question 8

True or False: Compounds are substances formed from two or more different elements.

Answer 8

True

Question 9

What is the chemical formula for water?

Answer 9

H2O

Question 10

Fill in the blank: The _____ of an element is the number of protons in its nucleus.

Answer 10

atomic number

Question 11

What is a chemical reaction?

Answer 11

A process that involves the rearrangement of the molecular or ionic structure of a substance.

Question 12

What is the law of conservation of mass?

Answer 12

Mass is neither created nor destroyed in a chemical reaction.

Question 13

What is an ion?

Answer 13

An atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

Question 14

True or False: An acid has a pH less than 7.

Answer 14

True

Question 15

What is the pH scale used for?

Answer 15

To measure the acidity or alkalinity of a solution.

Question 16

What is a catalyst?

Answer 16

A substance that increases the rate of a chemical reaction without being consumed in the process.

Question 17

Fill in the blank: _____ are substances that can donate protons in a chemical reaction.

Answer 17

Acids

Question 18

What is the difference between a physical change and a chemical change?

Answer 18

A physical change alters the form of a substance but not its chemical composition, while a chemical change results in the formation of new substances.

Question 19

What is an example of a chemical change?

Answer 19

Rusting of iron

Question 20

What is the main gas produced during photosynthesis?

Answer 20

Oxygen

Question 21

True or False: All metals are solid at room temperature.

Answer 21

False

Question 22

What is an alkali metal?

Answer 22

A group of elements in Group 1 of the periodic table that are highly reactive.

Question 23

What do we call the horizontal rows in the periodic table?

Answer 23

Periods

Question 24

Fill in the blank: The _____ of an element is the average mass of its isotopes.

Answer 24

atomic mass

Question 25

What is a covalent bond?

Answer 25

A chemical bond that involves the sharing of electron pairs between atoms.

Question 26

What do we call the substances that are present before a chemical reaction?

Answer 26

Reactants

Question 27

What is a solution?

Answer 27

A homogeneous mixture of two or more substances.