Chemistry Jeopardy

The name is Bond, Chemical Bond

100

What is the formula of beryllium hydroxide? What type of bond is this?

Be(OH)₂

This is an ionic bond.

200

Explain why the formula for potassium oxide is K₂O instead of KO.

Potassium is in group 1, only 1 electron in its outershell. Oxygen requires 2 more electrons to complete its outershell so oxygen requires 2 potasisum ions for this.

300

Draw out the bonding in N₂

3 pairs of shared electrons

2 free electrons/1 pair of lone electrons.

400

What are 2 differences between diamond and graphite?

Explain the differences. 

Diamond - cannot conduct electricity - no free electrons

Diamond - stronger - all 4 carbons bonded, no layers

Graphite - layers can slide over each other - has layers weakly bonded together (only 3 bonds per carbon)

500

Which of the following is likely to have a higher melting point - AgI or C₂H₆?

Why?

AgI 

Ionic bonds - lattice structure. High electrostatic attraction. 

Maths but make it Chemistry

100

What is the mass of one mole of NaCl?

58

200

If 0.25 moles of carbon dioxide are produced in a reaction, how much space will it occupy in dm3?

6 dm3

300

3 minutes

11.25g of hydrated copper sulfate CuSO4 . xH2O is heated until it loses all of its water. It is reweighed and its mass is 7.19.

What is the formula of the hydrated salt?

CuSO₄ . 5H₂O

400

3 mins

25cm3 of 0.15mol/dm3 barium hydroxide was required to neutralise 12.80cm3 of nitric acid. What is the concentration of nitric acid in g/dm3?

Equation: 

Ba(OH)_{2 (aq)} + 2HNO_{3 (aq)} --> Ba(NO₃)_{2 (aq)} + 2H₂O _(l)

Mols of Ba(OH)2 = 0.15 x 0.025 = 0.00375 mols

Mols of HNO3 = 0.00375 x 2 = 0.0075

Concentration of HNO3 = 0.0075/0.0128 = 0.59mols/dm3

Concentration of HNO3 = 0.59 x 63 = 37.17g/dm3

500

2 mins

9.2g of sodium reacted with 8.0g of sulfur to produce sodium sulfide. 

2Na + S --> Na₂S

Which reactant is the limiting reactant? Explain.

Mols Na = 9.2/23 = 0.4

Mols of S = 8.0/32 = 0.25

Na is the limiting reactant. 

This is because to react with all of 0.25mols of S, we require 0.25x2 = 0.5mols of Na but we only have 0.4mols

Break it up

100

What is the CIE definition for electrolysis?

Chemical breakdown

Ionic Compound

Aqueous or Molten

Passage of electricity

200

What is observed at the anode in the electrolysis of molten sodium chloride?

Bubbles/Green gas/Blue litmus paper bleaches white

(Chlorine gas observations) 

300

I am trying to electroplate Iron with silver using a silver salt. What should my cathode and anode be?

Cathode - Iron

Anode - Silver

400

What is formed at the anode of aqueous concentrated sodium chloride? Write out the ionic half-equation for this reaction.

Chlorine gas 

2Cl- + 2e- -> Cl₂

500

What is formed at the anode of aqueous concentration sulfuric acid? Write out the ionic half-equation.

Oxygen gas

4OH- --> 2H2O + O2 + 4e-

That's a bad reaction

100

Is freezing exothermic or endothermic?

Exothermic

200

H2 + Cl2 --> 2HCl

Is this reaction exothermic or endothermic? Use the bond energies below to help you out.

H--H = 436

Cl--Cl = 242

H--Cl = 431

(436+242)-(2x431) = -184kJ

300

Draw the reaction pathway diagram of the formation of ammonia. Include the label of ΔH with an arrow. 

Exothermic so reactants are higher than products on y axis, Ea must be shown and ΔH line is between products and reactants (pointing downwards) 

400

3 mins

Iron reacts with copper(II) sulfate to form iron(II) sulfate and copper.

Write out: 

- The net ionic equation incl state symbols

- The half ionic equations (both) incl state symbols

- Identify the reducing agent. 

Fe⁰ _(s) + Cu²⁺ _(aq) --> Fe²⁺_(aq) + Cu⁰_(s)

Fe⁰ --> Fe²⁺ + 2e^- 

Cu²⁺ + 2e^- --> Cu⁰

Fe⁰ is the reducing agent as it gets oxidised (loses electrons)

500

2 mins

2 drops of potassium manganate are added to a well of potassium iodide. 

What is the colour change seen? 

Write out the half- ionic equation for iodine incl state symbols. 

Identify whether potassium iodide is an oxidising agent or a reducing agent. 

Colourless to brown. 

2I^- _(aq) --> I_{2 (aq)} + 2e^-

KI is a reducing agent as it gets oxidised (I- loses electrons)

Chemicals and tables

100

30s

What is the trend in reactivity of group 7 halogens? 

decreases down the group

200

1 min

Write out the metals in the reactivity series from least reactive to most reactive. Include carbon and hydrogen.

Gold, Silver, Copper, Hydrogen, Iron, Zinc, Carbon, Aluminium, Magnesium, Lithium, Sodium, Potassium

300

1 min

Is there a reaction when bromine water is added to aqueous potassium iodide? 

If no, why not?

If yes, what colour change would you see?

Yes

Colourless to Yellow/brown

400

1 min

How can you make lead sulfate?

Include all the chemicals you would use and write out the ionic equation for this incl state symbols.

any 2 soluble salts

Pb²⁺ _(aq) + SO₄^2- _(aq) --> PbSO_{4 (s)}

500

4 mins

A chemist is trying to find the concentration of a solution of calcium hydroxide. 

The chemist has a 0.1M of dilute hydrochloric acid. 

The chemist finds that they need to use 0.02 dm³ of hydrochloric acid (in burette) to neutralise 0.025cm³ of calcium hydroxide (in conical flask). The chemist used thymolphthalein indicator for this. 

What is the concentration of calcium hydroxide in mol/dm³?

What was the colour change seen? 

Hint: You will need a balanced chemical formula to figure this out. 

Colour change: Blue to colourless

Concentration: 

Ca(OH)₂ + 2HCl --> CaCl₂ + 2H₂O 

Mol of HCl: 0.02 x 0.1 = 0.002

Mol of Ca(OH)₂ = 0.002/2 = 0.001

Concentration of Ca(OH)₂ = 0.001/0.025 = 0.04 mol/dm³