Chemistry 1 - Atoms, bonding and moles (C1 - C4)

Question 1

Which sub atomic particle has a positive charge?

Answer 1

Proton

Question 2

Which sub atomic particle has a negative charge?

Answer 2

Electron

Question 3

Which sub atomic particle has neutral charge?

Answer 3

Neutron

Question 4

Which sub atomic particle has a mass too small to be relevant?

Answer 4

Electron

Question 5

What is the atomic number?

Answer 5

The number of protons, therefore the number of electrons

Question 6

What is the relative atomic mass?

Answer 6

The total number of protons and neutrons.

Question 7

What is the charge of an atom? Why?

Answer 7

No charge because they have an equal number of protons and electrons.

Question 8

What is an ion?

Answer 8

An atom that has lost or gained electrons, giving it a negative or positive charge.

Question 9

What is an isotope? How does it differ from a normal atom?

Answer 9

Atoms of the same element with different number of neutrons. They have identical chemical properties but their physical properties like density can differ.

Question 10

How many electrons go in the first shell?

Answer 10

2

Question 11

How many electrons go in the subsequent shells to the first?

Answer 11

8

Question 12

What does the group number represent?

Answer 12

The number of electrons in the outer most shell.

Question 13

Which type of element usually loses electrons?

Answer 13

Metals

Question 14

Which type of element usually gains electrons?

Answer 14

Non-metals.

Question 15

Why are the Group 0 noble gases very unreactive?

Answer 15

Because they have full outer shells.

Question 16

What are the elements in group 1 called?

Answer 16

Alkali metals

Question 17

What happens to the alkali metal’s melting and boiling points going down the group?

Answer 17

They decrease.

Question 18

What happens to the alkali metal’s reactivity going down the group?

Answer 18

It increases

Question 19

What do alkali metals form in reactions?

Answer 19

1+ ions to make ionic compounds. These are generally white and dissolve in water, giving colourless solutions.

Question 20

What happens when the alkali metals react with water?

Answer 20

They all react with water to produce hydrogen and an alkaline solution containing the metal hydroxide.

Question 21

What are the elements in group 7 called?

Answer 21

The Halogens

Question 22

What do halogens form?

Answer 22

They form ions with a single negative charge in their ionic compounds with metals.

Question 23

How do Halogens form covalent compounds?

Answer 23

By sharing electrons with other non metals.

Question 24

What happens to the reactivity of the Halogens going down the group?

Answer 24

They decrease.

Question 25

What are the elements in the middle section of the periodic table called?

Answer 25

The transition elements.

Question 26

What are transition elements used as?

Answer 26

Important industrial catalysts.

Question 27

How does ionic bonding work?

Answer 27

The atoms involved lose or gain electrons to form charged particles called ions.

Question 28

How are ionic compounds held together?

Answer 28

Strong forces of attraction between their oppositely charged ions.

Question 29

What state are all ionic compounds at room temperature?

Answer 29

Solid

Question 30

How does covalent bonding work?

Answer 30

Covalent bonds are formed when atoms of non-metals share pairs of electrons with each other.

Question 31

Why are the melting and boiling points of substances with simpler molecules lower?

Answer 31

Because the inter-molecular forces are weak.

Question 32

How do you find the mole number of a compound?

Answer 32

Moles = mass / relative formula mass or n = m / Mr

Question 33

How do you find the relative formula mass of a compound?

Answer 33

Add up the relative molecular mass of all the elements in it.

Question 34

What is the Avogadro constant?

Answer 34

6.02 x 10(to the 23)

Question 35

What is the yield of a chemical reaction?

Answer 35

How much product is made.

Question 36

What is the percentage yield of a chemical reaction?

Answer 36

How much product is made compared with the maximum amount that could be made (100%)

Question 37

What is Atom Economy?

Answer 37

A measure of the amount of starting materials that end up as useful products.

Question 38

What is the equation for Atom Economy?

Answer 38

% Atom economy = Mr of the desired product from equation / Sum of the Mr of the reactant from equation x 100%

Question 39

What is the equation for concentration?

Answer 39

Concentration (g/dm cubed) = amount of solute (g) / volume of solution (dm cubed)

Question 40

How do you convert cm into dm?

Answer 40

x 1000

Question 41

What is TItration?

Answer 41

A method used to measure accurately what volumes of acid and alkali react together completely

Question 42

What are the 7 stages of Titratrions? (Write on paper then check answer)

Answer 42

1. Measure an alkali into a conical flask with volumetric pipette. Wash the pipette with distilled first. 2. Add a few drops of acid/base indicator into the solution in the conical flask and swirl. 3. Rinse the burette with water and then with some of the acid allowing some acid to pass through the tap. Then pour the acid you are going to use into the burette. Measure volumes of the solution to the nearest 0.05 cm cubed. 4. Record the reading on the burette. Then open the tap to release a small amount of acid into the flask. Swirl the flask to make sure that the two solutions are mixed. 5. Keep on repeating step 4 until the indicator in the flask changes colour. This shows when the alkali in the flask has completely reacted with the acid added from the burette. Record the reading on the burette and work out the volume of acid that has run into the flask. This volume is a titre. 6. Repeat the whole process three times. Discard any anomalous results. Alternatively, keep repeating the titration until you get two results within 0.1 cm cubed of each other. These precise results are concordant. Then calculate a mean value to give the most accurate results as possible. 7. Now you can use your results to calculate the concentration of the alkali in mol/dm cubed.

Question 43

What is the equation to find the number of moles of gas?

Answer 43

Moles of gas = vol of gas(dm cubed) / 24dm cubed

Question 44

What indicator can be used in a titration?

Answer 44

``` Methyl Orange (Yellow to red) Phenolphthalein (Pink to colourless) ```