quiz 5

Question 1

carbonic acid immediately decomposes to produce…

Answer 1

H2CO3 (aq) -> H20 (L) + CO2 (g)

Question 2

sulfurous acid immediately decomposes to produce…

Answer 2

H2SO3 (aq) -> H20 (L) + SO2 (g)

Question 3

ammonium hydroxide immediately decomposes to produce…

Answer 3

NH4OH (aq) -> H2O (L) + NH3 (g)

Question 4

ammonium sulfide immediately decomposes to produce…

Answer 4

(NH4)2S (aq) -> H2S (g) + 2NH3 (g)

Question 5

when is activity taken into account for a chemical reaction

Answer 5

when determining whether a metal will displace another metal (single displacement). in order to do so, the metal must be more active than the metal it is displacing.

Question 6

a reaction occurs in a double displacement if…

Answer 6

• a precipitate is formed through the formation of an insoluble substance
• H2O (L) is formed through an acid-base reaction
• gas is formed through decomposition

Question 7

what makes a solution a good conductor of electricity

Answer 7

dissolved ions must be present to make it a conductor of electricity. a good conductor of electricity is called and electrolyte

Question 8

polar compounds

Answer 8

have both a partial positive and partial negative charge.. an example of this is water

Question 9

signs of a chemical change

Answer 9

• color change
• production of an odor (g)
• change of temperature
• evolution of a gas (formation of bubbles)
• precipitate

Question 10

solute

Answer 10

substance being dissolved

Question 11

solvent

Answer 11

substance doing the dissolving

Question 12

melting

Answer 12

process by which pos and neg charges are separated w/o solvent present

Question 13

acid-base reaction

Answer 13

• contains an acid (H___) and base (typically ___OH, though it can be a carbonate, sulfide, or sulfite as well) and forms H20 (or S20)
• always exothermic
• always double displacement

Question 14

precipitation reactions

Answer 14

always double displacement reactions. when a solid is formed

Question 15

redox reactions

Answer 15

• when a compound reacts with oxygen or when the charge of an atom changes during reaction.
• all single displacements are redox
• the O2 or substance with the charge is the oxidant, while the substance without the charge is the reductant

Question 16

when the sign of ∆H is negative

Answer 16

• the reaction is exothermic
• kJ is on the products side
• reaction feels hot
• reactants themselves contain energy than the products (through the law of conservation of energy, both sides must be equal, therefor the energy produced in the reaction was previously contained in the reactants)

Question 17

when ∆H is positive

Answer 17

• the reaction is endothermic
• kJ is a reactant
• energy is being absorbed and the reaction feels cool
• reactants have less energy than products

Question 18

empirical formula

Answer 18

• most simplified version of the molecular formula (true formula)
• n*empirical formula=molecular formula

Question 19

gas evolution reactions

Answer 19

-an aqueous reaction where gas is formed