Moles and Emprical Formulae & Electrolysis - Quest
Moles and empirical formulae
- What is the molar mass of this acid: Ch3C(CH)2COOH ?
- How much carbon dioxide is made when 440g propane, C3H8 is burned?
- What is the empirical formula for hexane, C6H14?
- 110g of sulfuric acid contains 2.04%H, 32.65% S and 65.31% O. Work out the empirical formula of sulfuric acid.
- Which type of ions move towards the cathode during electrolysis?
- Write down two half equations that represent electrolysis of Pbl2
- Write down two quantities that change the amount produced at an electrode.
- How much charge is transferred by a current or 0.2A for 3 hours?
Moles and Emprical Formulae & Electrolysis - Answe
Moles and Empirical Formulae
- C3 H7
- H2 SO4
- Negative ions - cations.
- Pb2+ + 2e = Pb and 2l - 2e = l2
- Current and time
Quantitive analysis & Ionic Equations - Questions
- What is a solute?
- How many grams of sodium are there in 25g of salt?
- You have a 10cm3 of a solution. You want to make it 10 times as dilute. How much water do you add?
- There is 1 mole of salt in 2dm3 of water. What is the concentration of the solution in mol/dm3?
- Write a word equation for the reaction of silver nitrate and sodium iodide.
- Why are sodium ions and nitrate ions after spectator ions?
- Why do you wash a precipitate in distilled water when making a dry sample?
- Write an ionic equation for the reaction of silver nitrate and sodium bromide.
Quantitive analysis & Ionic Equations - Answers
- A substance that dissolves in a liquid.
- Silver nitrate + sodium iodide = silver iodide + sodium nitrate
- If the solution used to make the precipitate was potassium nitrate instead of sodium nitrate the same precipitate would occur as sodium potassium and nitrate ions remain in solution.
- To remove traces of the solution filtered with the precipitate.
- Ag+ + Br- = AgBr
Titrations & Gas volumes - Questions
- Alakli is slowly added to acid. How does the Ph change?
- If number of moles - concentration x volume in dm3, write down the relationship for concentration.
- Why are titration carried out several times before a volume is decided?
- 23.6 cm3 os a solution of 0.12 mol/dm3 hydrochloric acid react with 25.0 cm3 of sodium hydroxide colution. What is the concentration of the sodium hydroxide solution?
- A reaction gave off 96cm3 of sulfur dioxide. How may moles were made?
Titrations & Gas volumes - Answers
- It increases
- Concentration = number of moles / volume
- To increase the reliability
- 0.113 mol/dm3
Equilibria & Strong and weak acids - Questions
- At equilibrium, the reaction A+B=C+D has 1 mole of A and B and 3 moles of C and D. Where is the position of the equilibrium?
- What happens to the equilibrium in the reaction of gases: N2+3H2=2NH3 is the pressure is increased?
- What are the conditions used in the Contact Process?
- Why is it called a compromise temperature in the Contact Process?
Strong and weak acids
- Strong acids break into their ions completely if put into water. What happens to weak acids when they are put into water?
- Explain why ethanoic acid is a weak acid.
- One ion makes a solution into an acid. Which one?
- Explain why strong acids react faster than weak acids.
Equilibria & Strong and weak acids - Answers
- To the right
- Moces to the right
- 450 Oc, atmospheric pressure, catalyst of vanadium pentoxide. V2O5.
- High temperature reduce the yielf of the reaction but the rate would be too low at low temperatures, so a somprimise is found, 450 Oc.
Strong and Weak acids
- Not all molecules seperate ions.
- The ionisation of ethanoic acid in water is not compelte. It is a reversible reaction where the position of equilibrium lies to the left.
- In strong acids the concentration of H+ is higher, so collision frequency is greater.