Chemistry Test #1 Flashcards

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1
Q

What are the TWO characteristics of matter?

A

It has mass and occupies space

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2
Q

What is the smallest complete unit of matter?

A

Atom

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3
Q

Difference between pure substances and mixtures?

A

a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.

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4
Q

Difference between an element and a compound?

A

Element: Pure substance consisting of one type of atom. Compound: Pure substance consisting of two or more different atoms.

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5
Q

Difference between homogenous and heterogenous mixtures?

A

Heterogeneous mixtures have visually distinguishable components, while homogeneous mixtures appear uniform throughout

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6
Q

What is another name for a homogeneous mixture?

A

Solution

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7
Q

Examples of chemical properties?

A

flammability, toxicity, acidity, reactivity (many types), and heat of combustion.

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8
Q

Examples of physical properties?

A

density, color, hardness, melting and boiling points, and electrical conductivity.

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9
Q

Difference between chemical and physical changes?

A

Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula.

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10
Q

A substance boils and evaporates.

Chemical or physical change.

A

Physical Change.

The substance is still made up of the same chemical composition just at a different temperature.

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11
Q

Wood is chopped up and cannot be turned back into a log.

Chemical or physical change?

A

Physical change.

The wood is still the same wood, just chopped up.

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12
Q

Salt dissolves in water

A

Chemical Change.

The salt dissolves in water, becoming a solution and is irreversible.

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13
Q

5 signs a chemical change has happened?

A

color change, formation of a precipitate, formation of a gas, odor change, temperature change

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14
Q

What are subatomic particles?

Compare them on size, location, and electric charge.

A

Protons, Neutrons, Electrons.

PROTONS- 1AMU
NUETRONS- 1AMU
ELECTRONS -0 AMU
Protons and neutrons are in the centre of the atom, making up the nucleus. Electrons surround the nucleus

Protons have a positive charge. Electrons have a negative charge. Neutrons have no charge.

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15
Q

What is the Atomic number?

A

the number of protons in the nucleus of an atom

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16
Q

What is the Atomic mass?

A

Mass of an atom

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17
Q

How many electrons can fit in the first energy level?

A

2

18
Q

How many electrons can fit in the 2nd energy level

A

8

19
Q

How many electrons can fit in the 3rd energy level?

A

8

20
Q

How many electrons can fit in the 4th energy level?

A

18

21
Q

What is a valence electron? What does it dictate?

A

a single electron or one of two or more electrons in the outer shell of an atom that is responsible for the chemical properties of the atom

22
Q

Difference between a coefficient and a subscript?

A

Subscripts - Part of the chemical formulas of the reactants and products that indicate the number of atoms of the preceding element.

Coefficient - A small whole number that appears in front of a formula in a balanced chemical equation.

23
Q

Difference between an atom and an ion?

A

An atom has no electrical charge. Ions have an electrical charge because they have an imbalance of protons and electrons

24
Q

Difference between a cation and an anion?

A

Cations are positively charged ions

Anions are negatively charged ions

25
Q

Ionic compounds involve transfer or sharing of valance electrons?

A

Transfer

26
Q

What type of elements form ionic bonds?

A

metals and non metal ions

27
Q

Metals usually form cations or anions?

A

Cations

28
Q

Non metals usually form cations or anions?

A

Anions

29
Q

is non metal or metal written first in an ionic compound?

A

Metal

30
Q

a precipitate forms after a reaction, is it the same thing as freezing when a solid forms? why?

A

No, precipitate is chemical, freezing is physical

31
Q

How to calculate the number of protons, electrons, and neutrons in a neutral atom?

A
# of protons = the atomic number
# of neutrons = mass # - atomic #
# of electrons= # of protons in a neutral atom
32
Q

Difference between groups and periods?

A

groups are vertical

periods are horizontal

33
Q

How can you tell the number of valence electrons an element has

A

by what group its in

34
Q

Name this compound Mg3N2

A

Trimagnesium dinitride

35
Q

What is a polyatomic ion? How do you name them?

A

is a covalently bonded set of two or more atoms. The cation is written first in the name; the anion is written second in the name.

36
Q

What are two ways non metals can obtain a full valence shell?

A

transfer or share

37
Q

Are molecular compounds always made up of non metals?

A

yes, they share there electrons

38
Q

Can a covalent bond share multiple pairs of electrons? Example?

A

Yes, carbon dioxide

39
Q

Name this compound: PBr5

A

Phosphorus Pentabromide

40
Q

What is the formula for sulphur trioxide?

A

SO3

41
Q

What can be said about how diatomic elements occur in nature ?

A

Bonded with another of the same element

42
Q

What is combining capacity

A

Number of bonds that need to form in order to have a stable atom