What is the difference between a homogeneous mixture and a heterogeneous mixture?

Homogeneous is uniform, heterogeneous is different

How do we calculate the number of protons and electrons in an element?

By looking at the atomic number

What are the reactants and products in a chemical reaction?

Start with reactants, end with products

What is a valence electron? How many valence electrons does boron have?

electrons on the outer most ring, 3

Why are the noble gases not reactive?

Their outer electron ring is full

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8th grade chem review

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Chem

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Questions 20

Answers

1
Which part of the periodic table is composed of metals?
Left
the elements touching the zig zag staircase
Right
the last group
2
What is the difference between a homogeneous mixture and a heterogeneous mixture?
Homogeneous is uniform, heterogeneous is different
They mean the same thing
Homogeneous is different, heterogeneous is uniform
Homogeneous is a mixture and heterogeneous is a compound
3
How do we calculate the number of protons and electrons in an element?
By adding the atomic mass and atomic number
By subtracting the atomic mass and atomic number
By looking at the atomic number
By looking at the atomic mass
4
Which element does this Bohr Model belong to?
Vanadium (V)
Sodium (Na)
Magnesium (Mg)
Neon (Ne)
5
How many protons does Lithium have?
6.941
3
7
4
6
What law is being demonstrated in the picture?
Law of conservation of mass
Law of chemistry
Law of measuring
Law of conservation of elements
7
How many neutrons does Flourine have?
10
19
18.998
9
8
I mix grape Kool Aid powder into water. Which is the solute in the example?
The Kool Aid/water mixture
The Kool Aid powder
The water
Oranges and bananas
9
Which phase change is going from a liquid to a gas?
Condensation
Melting
Freezing
Boiling
10
Which is an example of a suspension?
Pepper in water
Kool-Aid
Milk
Chex Mix
11
How many carbon atoms are in the following compound: C6H12O6
0
6
12
24
12
What property of metals allows them to be flattened into thin sheets such as aluminum foil?
Malleability
Ductility
Magnetism
Conductivity
13
Which of the following is an example of a physical change?
A metal can rusting
Burning paper
Formation of a precipitate
Tearing paper
14
What is the best element to use as a conductor?
Chlorine (Cl)
Helium (He)
Arsenic (As)
Copper (Cu)
15
Which is an indicator that a chemical reaction has taken place?
Formation of a precipitate
Color change
Rust has formed
All answers are correct
16
What are the three states of matter?
element, atom, compound
Metal, metalloid, nonmetal
Solid, liquid, gas
Solid, metal, gas
17
What are the reactants and products in a chemical reaction?
Start with products, end with reactants
They are the same thing
Start with reactants, end with products
Products always equal reactants
18
What happens to molecules in water as we move from a liquid to a solid state?
They slow down
They don't change
They speed up
Are you crazy? Molecules don't move.
19
What is a valence electron? How many valence electrons does boron have?
electrons on the inner most ring, 5
electrons on the inner most ring, 3
electrons on the outer most ring, 3
electrons on the outermost ring, 5
20
Why are the noble gases not reactive?
They are gases
They don't like the other elements
Their outer electron ring is full
They are metals

8th grade chem review Flashcards | StudBud