Chapter 4 Flashcards

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1
Q

A physical change is..

A

Doesn’t change the nature or the characteristic properties of matter
Atoms and molecules of the substance do not change

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2
Q

What are the three states of physical change

A
  1. Dissolution
  2. Deformation
  3. Change of state
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3
Q

A chemical change is..

A

Changes the nature and characteristic properties of matter
The bonds between atoms are rearranged and new molecules are formed

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4
Q

What are the five signs of a chemical change

A
  1. Release of gas
  2. Emission or absorption of heat
  3. Emission of light
  4. A change in colour
  5. Formation of a precipitate
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5
Q

What does the law of conservation of mass state

A
  • the total mass of reactants is always equal to the total mass of products
  • this means that we cannot gain or lose matter in an equation. Both sides are equal
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6
Q

Suppose 111.7g of Fe metal rusts. We weigh the rust and find that the rust has a mass of 159.7g. What mass of oxygen reacted to the iron?

A

111.7g + x = 159.7g
Solve for x= 48g

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7
Q

Describe balancing a chemical equation

A

Is placing coefficients before each reactant and product so:
- atoms on the reactants side is equal to atoms on the product side
- equations have to be balanced because in reality chemical reactions cannot destroy atoms: only rearranging them.

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8
Q

How to balance equations

A
  1. You may introduce coefficients (big #s in front of formulas or atomic symbols)
  2. You cannot change or add subscripts
  3. For each element: total atoms on the left = total atoms in the right
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9
Q

Give an example of a balanced equation

A

CH4 + 2 O2 = CO2 + 2 H2O

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10
Q

How to balance a polyatomic

A

Keep polys together if they appear in the products and reactants. If they don’t, then you must balance the atoms individually.

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11
Q

Give an example
Of balanced poly

A

2 RbNO3 + 1 BeF2 = 1 Be(NO3)2 + 2 RbF

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12
Q

What are the four subscript brackets

A

Solid (s)
Liquid (l)
Gas (g)
Aqueous (aq)

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13
Q

What is aqueous

A

Meaning dissolved in water

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14
Q

What is a synthesis reaction

A

-formation of a complex molecule from atoms or simple molecules
-combination of 2 or more reactants to form a new product
- generic formula: A + B = AB

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15
Q

Example of synthesis reaction

A

N2 + 2 O2 = 2 NO2

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16
Q

Give formula for photosynthesis

A

6 CO2 + 6 H2O = C6H12O6 + 6 O2

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17
Q

What is a decomposition reaction

A

The transformation of complex molecules into simpler molecules or atoms.
Opposite of synthesis reaction
Generic formula; AB = A + B

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18
Q

Example of decomposition reaction

A

2H2O = 2 H2 + O*2

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19
Q

What is an oxidation reaction

A

-chemical change in which a metal reacts with oxygen
-most commonly known as the reaction that forms rust
-oxidation releases heat

20
Q

Example of oxidation reaction

A

Metal + O2 = metalO2

21
Q

What are other oxidation reactions

A

Combustion and cellular respiration

22
Q

What is a combustion

A

Form of oxidation that releases a large amount of energy

23
Q

Give an example of combustion

A

2 C4H10 (g) + 13 O2 (g)= 8 CO2 (g) + 10 H*2O + 5316 kJ (energy)

24
Q

What is cellular respiration

A

Chemical change in which glucose and oxygen are used to generate energy. The reaction also produces co2 and H2O

25
Q

Give example of cellular respiration

A

C6H12O6 (aq) (glucose) + 6 O2 (oxygen) = 6 H2O (water) + 6 CO2 (carbon dioxide) + 170kJ (energy)

26
Q

What are the types of combustion and give a definition

A

Rapid: releases a great deal of energy within a short period of time
Spontaneous: fuel reaches its ignition temperature without any energy from outside source
Slow; occurs over a very long period of time

27
Q

To create fire you need:

A
  1. Ignition source (flame or hot temp)
  2. Oxidizer (oxygen)
  3. Fuel (wood, gas, paper)
28
Q

What is a precipitation reaction

A

Formation of an insoluble solid substance, “precipitate” when 2 solutions are combined.

29
Q

Give example of precipitation

A

Vinegar and milk

30
Q

What is acid base neutralization

A

Reacting of an acid with a base to form a salt and water
Generic formula: acid (aq) + base (aq) = salt (aq) + water (l)

31
Q

Steps to do acid base neutralization

A
  1. Identify the acid and base
  2. Use cross over rule to write formula of the salt
  3. Balance equation
32
Q

What is stoichiometry

A

Refers to relative quantities of moles in a balanced chemical equation

33
Q

Neutralize NaOH and Back

A
34
Q

Neutralize H2SO4 and RbOH

A
35
Q

what is stoichiometry?

A

refers to the relative quantities of moles in a balanced chemical equation

36
Q

What is exothermic

A

process that releases heat and light to the surroundings (becomes hot)

37
Q

give an example of exothermic

A

combustion

38
Q

explain the energy of exothermic reaction

A

broken bond energy is greater than energy needed for the newly formed bonds

39
Q

what is endothermic

A

process where the reactions absorb energy from the surroundings (cools surroundings)giv

40
Q

give an example of endothermic

A

recharging a battery

41
Q
A
42
Q

What is nuclear energy

A

The strong and weak nuclear forces exist within the nucleus of atoms and helps keep matter together.
Without these forces atoms would simply fall apart

43
Q

What is nuclear stability

A

Refers to the state of a nucleus in which the nuclear force is greater than the forces of electrical repulsion between protons

44
Q

What is radioactivity

A

Natural process in which an unstable atom spontaneously transforms into a more stable atom, or several more stable atoms, while releasing energy as radiation

45
Q

What is nuclear fission

A

Nuclear reaction in which the nucleus of a large atom is split to form two or more lighter atomic nuclei

46
Q

Nuclear fusion

A

Nuclear fusion in which two small atomic nuclei join together to form one heavier nucleus.