A3.0 Flashcards by Emily Maltais

Q

What is an exothermic reaction ?

A

A chemical reactions that release energy.
Usually in the form of either heat, light, electricity, or a combination of those.
Ex. a burning candle

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Q

What is an endothermic reaction ?

A

A chemical reaction that absorbs energy.
The reaction will not begin on its own but rather requires electricity or some kind of “activation” energy.
Usually feel cold.
Ex. instant cold packs

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Q

What is a precipitate ?

A

A solid with low solubility that forms from a solution.

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Q

The Law of Conservation of Mass says:

A

In a chemical reaction, matter cannot be created or destroyed.

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Q

What is used when there is more than 1 of a compound in an equation in order to balance it ?

A

Coefficients

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Q

5 types of chemical reactions ?

A

1) Formation
2) Decomposition
3) Hydrocarbon Combustion
4) Single Replacement
5) Double Replacement

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Q

What is a Formation Reaction:

A

Two elements combine to form a compound.
A + B = AB
These reactions are exothermic.
Are recognized by being the only reaction where both reactants are elements. (Not compounds)

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Q

What is a Decomposition Reaction?

A

A combined breaks down into its elements.
AB = A + B
These reactions are endothermic.
Recognized by being the only reaction with only 1 reactant.

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Q

What is a Hydrocarbon Combustion Reaction?

A

“Combustion” means to burn.
These reactions are exothermic.
the equation is always:
A hydrocarbon fuel + oxygen = carbon dioxide + water vapour
Recognized by having a hydrocarbon andoxygen as the reactants.

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Q

What is a Single Replacement Reaction?

A

An element reacts with a compound, a produces a new element and a new compound.
A+BC = AC + B
Recognized by having reactants that are a compound and an element that is not oxygen.

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Q

What is a Double Replacement Reaction?

A

2 compounds exchange ions to form 2 new compounds.
AB+CD = AD+CB
Recognized by being the only reaction where both reactants are compounds.

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Q

What type of reaction is this?

C6H12(l) + 9O2(g) =
6CO2(g) + 6H2O(g)

A

Hydrocarbon Combustion

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Q

What type of reaction is this?

CaCl2(aq) + Na2SO4(aq) =
CaSO4(s) + 2NaCl(aq)

A

Double Replacement

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Q

What type of reaction is this?

2Fe(s) + O2(g) = 2FeO(s)

A

Formation

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Q

What type of reaction is this?

Be(s) + 2LiBr(aq) =
BeBr2(aq) + 2Li(s)

A

Single Replacement

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Q

What type of reaction is this?

MnI4(aq) = Mn(s) + 2I2 (s)

A

Decomposition

Q

How many atoms are in a mole?

A

6.02 x 10^23

Q

6.02 x 10^23 is referred to as:

A

Avagadros number

Q

The mass of 1 mole of an element is called its:

A

Atomic molar mass (M)

*measures in g/mol

Q

Where is the atomic molar mass of an element found?

A

On the periodic table

Ex. Carbon= 12.01 g/mol
Sulfur= 32.07 g/mol

Q

How do we find the molar mass of compounds?

A

1) Write the chemical formula
2) List the number of atoms in each element
3) multiply this number by the molar mass of the element
4) Add the sums together

Q

What is the formula to

find the mass of a compound/element?

A

n= m/M

Q

The mole

concept and the Law of Conservation of Mass:

A

Remember that the total mass of reactants is always equal to the mass of the products.

Q

What is Specific Heat Capacity?

A

The amount of energy absorbed by 1g of a substance that causes it to increase in temperature by 1 degree Celsius (C)

Does water have an usually high specific heat capacity or an unusually low one?

Usually high the high specific heat capacity of water means that it can absorb lots of energy but stay at a constant temperature.

AP content:

- Hydrogen bonding in water is the attraction between a hydrogen atom of one molecule and an oxygen atom of another molecule. - Your genetic material (DNA) is held by h-bonds. DNA must be broken apart and replicated, so your body temperature is high enough that those a H-bonds break and reform frequently - Cities next to oceans experience more moderate temperatures because water can absorb heat without ganging temperature. - Vancouver is located next to a warm climate making it have a warmer average temperature year round. - Gander, Newfoundland is located next to a cool cute at making it having a cooler average temperature. - Lethbridge is landlocked, making it experience great temp variation form month to month.

What is Quantity of Thermal Energy

The amount of thermal energy (measures in joules) that is absorbed or released when the temperature of a substance changes.

What is the Quantity of Thermal Energy affected by?

- the mass of the substance (measured in grams) - the amount of change in temperature (measured in degrees Celsius) - how easily the substance changes temperature (measured by its specific heat capacity)

what is the formula to find quantity of thermal energy?

Q= mc∆t ``` m= mass of the substance (g) c= specific heat capacity (j/g•°C) ∆t= change in temperature (°C) ```

What is the hydrologic cycle?

- The movement of water molecules throughout the biosphere. | - Water in the cycle changes from solid to liquid to gas and vice versa

During phase changes, water changes state without changing....

temperature *this occurs because the thermal energy is going towards breaking the hydrogen bonds between water molecules rather than making the water molecules move faster.

Boiling is also called:

Vaporization

Melting is also called:

Fusion

Freezing is also called:

Solidification

What is the Heat of Fusion of a substance?

The amount of energy absorbed when 1 mol of the substance melts from solid to liquid without changing temperature. *it is the same as the heat of solidification which is the change from liquid to solid

What is the Heat of Vaporization of a substance?

The amount of energy absorbed when 1 mol of the substance evaporates from liquid to gas without changing temperature. *same as the heat of condensation, which is the change from gas to liquid

What is the formula for finding the Heat of Fusion or the Heat of Vaporization?

Hfus = Q/n or Hvap = Q/n ``` Hfus= heat of fusion Hvap= heat of vaporization Q= quantity of thermal energy (kJ) n= number of moles (mol) ```

All chemical reactions share what 2 features ?

1) A change in energy | 2) One or more substances are produced