practicals

Question 1

What is mol/dm^3 in a titration equation?

Answer 1

This is the concentration

Question 2

what is dm^3

Answer 2

decimetres cubed

Question 3

what must you do to any unit to make it decimetres cubed-dm^3

Answer 3

divide the number by 1000 to make it decimetres cubed

Question 4

What is the aim of titration?

Answer 4

The aim of titration is to find out the titrant. This is the amount of known solution added (usually an acid) to the unknown solution (usually alkali),you must add the known concentration until the solution turns neutral,you use this unit of added acid to work out the concentration of the unknown solution.

Question 5

Why do we need to find out the titrant?

Answer 5

The titrant is used to figure out the concentration in the uknown solution in an equation.

Question 6

what is dm^3 usually used to measure in the equations>

Answer 6

concentration=mol/dm^3 or volume=dm^3

Question 7

What is a neutral colour for the indicator for phaenolphaelin

Answer 7

colourless

Question 8

What is a neutral colour for Methyl Orange

Answer 8

Yellow

Question 9

What is a constituent?

Answer 9

A consituent is a part of something

Question 10

What is the goal of electrolysis?

Answer 10

It is the use of an electrical current to break down compounds containing ions,into their constituent elements.

Question 11

What is the substance being broke down called in electrolysis?

Answer 11

Electrolytes

Question 12

What are the electrodes made from?

Answer 12

Solids that conduct electricity

Question 13

Where do the positively charged ions go to during electrolysis?

Answer 13

the cathode (negative electrode)

Question 14

Where do negatively charged ions go in electrolysis?

Answer 14

The Anode (the positive electrode)

Question 15

What is the difference between compounds and mixtures?

Answer 15

compounds are chemicallybonded and mixtures are not.

Question 16

What does electrolysis seperate/break down?

Answer 16

Ionic compounds

Question 17

When can ionic compounds conduct electricity?

Answer 17

When they are molten or dissolved in water

Question 18

What is different when metals are more reactive than carbon?

Answer 18

They can be extracted from their ores using electrolysis

Question 19

Is electrolysis expensive or cheap?

Answer 19

Expensive

Question 20

What makes electrolysis expensive?

Answer 20

the high ammount of heat and electrical energy needed

Question 21

What is an endothermic reaction?

Answer 21

Taking in energy

Question 22

What is an exothermic reacton?

Answer 22

LEtting out energy,warming the environment.

Question 23

How many cm^3 of Hydrochloric acid is used in the changing temperatures practical?

Answer 23

30 cm^3

Question 24

IN the changing temperatures practical what is used to hold the hydrochloric acid? and what is this item holding the acid placed inside and why?

Answer 24

The polstyrene cup is holding the acid and is placed inside a beaer to stop it from falling over.

Question 25

what happens next after you put the acid into the cup and the cup into the beaker in the changing temp practical?

Answer 25

Using a thermometre,measure the temp (C) of the acid and the place 5cm^3 of sodium hydroxide into the cup and put a lid on with a small hole in it.

Question 26

What must you do after putting the lid on in the changing temp practical?

Answer 26

Put the thermometre through the hole in the lid and use the themometre to swirl,due to this being an exothermic reaction we look carefully at the temperature rise.

Question 27

What do you do when the reading on the thermometre stops increasing in the changing temp practical?

Answer 27

You record the highest temperature reached.Then repeat the experimetn wit 10 cm^3, of sodium hydroxide solution and repeat the experiment several more times,incrementally increasing the sodium hyydroxide solution by 5cm^3 each time.

Question 28

in the changing temp practical after rpeating the experiment,each time with 5cm^3 added,at what point do we stop and what do we do then?

Answer 28

We stop when we have added 40cm^3 and done the reaction,and we repeat the whole experiment one more time so you have two sets of results.

Question 29

in the changing temp practical after getting our two sets of results what do we do?

Answer 29

We calculate a mean of all the maximum heat values and make a chart,showing an increase and then a slow,sloping decrease.

Question 30

in the changing temp practical why doe the chart begin to decrease?

Answer 30

As ast first,when the chart is steep the hydrochloric acid and sodium hydroxide are reacting weel,andheating up,but when there is tooo much sodium hydroxide,as we are adding in increments each time,there isnt enough hydrochloric acid to react and some sodium hydroxide cant react.

Question 31

in the changing temp practical why do we use polystyrene cups,and a lid?

Answer 31

As polystyrene is a good thermal insualtor and the lid reduces heat loss.

Question 32

In the chart in the changing temp practical there is a maximum reached point due to...

Answer 32

SOme sodium hydroxide not being able to react as all of the hydrochloric acid has already reacted with other sodium hydroxide.

Question 33

in the changing temp practical why does the overall temperature decrease instead of staying at the greatest possible temperature?

Answer 33

The unreacted sodium hydroxide that is added does not react and heat up,so the room temperature sodium hydroxide cools down the temperature of the cup gradually.