Water

Question 1

What is a solution, a solvent and a solute?

Answer 1

A solution is a homogenous mixture, that is, it’s components are uniformly intermingled at the molecular level. Contains a solute dissolved in a solvent

A solvent is a substance, usually liquid which dissolved a solute

A solute is a substance, usually solid which is dissolved by a solvent

Question 2

Name some important uses of water as a solvent

Answer 2

Water is important as a solvent because:

• living things are made up of mostly water
• reactions that occur in us are done in aqueous solutions. Blood is mostly water transporting oxygen and nutrients . Urine is acqua outs and is used to expel wastes out of the body
• makes the oceans, important to all aquatic life on earth.
• used in cleaning in the home eg. Detergents , soaps, cleaners , bleach
• foods such as drinks and fruits containing aqueous solutions

Question 3

What is a polar substance?

Answer 3

A compound in which its atoms are arranged in such a way that creates a positive and negative end of a net dipole force

Question 4

What is a non polar substance?

Answer 4

A non polar substance is a compound whose atoms are arranged that there is no definite positive and negative end. There is no net dipole force

Question 5

What is a dispersion force?

Answer 5

A dispersion force is the weakest intermolecular force that occurs between non polar molecules. This attraction is created via the formation of a temporary dipole that is formed across a compound due to the random movement of electrons

Question 6

What is a dipole- dipole force?

Answer 6

A dipole dipole force is a force that occurs between polar molecules in which oppositely charged ends of each molecule are attracted to each other. This is the second strongest intermolecular bond

Question 7

what is dynamic equilibrium?

Answer 7

an equilibrium where molecules are undergoing the forward as well as the back reaction at the same rate

Question 8

what is enthalpy?

Answer 8

the heat content of a system. thus us the total of all the kinetic and potential energies for one mole of a substance

Question 9

what is molarity?

Answer 9

the number of moles of solute per litre of solution

the formula for molarity is given by

c=n/v

Question 10

what is a saturated solution?

Answer 10

a solution where no more solute can dissolve, an excess of solute remains at the bottom of the solution

Question 11

what is the specific heat capacity of a substance?

Answer 11

the amount of heat energy required to raise the temperature of 1 gram of the substance by 1 degree celcius

Question 12

what is thermal pollution and why is it significant for marine ecosystems?

Answer 12

thermal pollution is the release of heat into the environment, particularly pumping warm water from the power plant cooling towers into rivers or lakes

thermal pollution is significant for marine ecosystems because:

• affects the solubility of gases such as O2 and CO2 as temperature increases their solubility decreases
• fish eggs fail to hatch when temperature is too high
• encourages temperature fluctuations in the water, altering the environment for marine life
• organisms which rely on temperature for breeding and migration may get confused and start these events at the wrong time

Question 13

what is a calorimeter?

Answer 13

a calorimeter is a piece of apparatus used to measure heat changes in dissolution’s or changes of state.

Question 14

what is a calorimeter usually made from?

Answer 14

• lid
• insulating layer
• themometer
• reaction mixture

Question 15

what is the formula for heat content in a system

Answer 15

q=mCAT where A is delta

Question 16

what does a low specific heat capacity correlate to?

Answer 16

a low specific heat capacity correlates to less joules of energy needed to increase the temperature

Question 17

what are some limitations for the calorimeter?

Answer 17

• heat is always lost to the surroundings
• only certain reactions can be measured
• reactants in the calorimeter may not be well-mixed