Acids and Bases & Reacting Masses - Questions
Acids and bases
- What's the base needed to make zinc sulfate?
- Which salt is made when magnesium hydroxide reacts with sulfuric acid?
- Write a balanced symbol equation for the reaction between HCl and ZnO.
- Which ions are responsible for making alkaline solutions?
- Write down the relative formula mass of calcium nitrate, Ca(NO3)2
- Explain why mass is conserved in a chemical reaction.
- Tim made 24g of crystals instead of 32g. What's the percentage yield?
- How much carbon dioxide is made in the complete thermal decomposition of 59.5g nickel carbonate, NiCO3?
Acids and Bases & Reacting Masses - Answers
Acids and Bases
- Zinc Oxide, Zinc hydroxide or Zinc carbonate.
- Magnesium sulfate.
- ZnO + 2HCl = ZnCl2 + 2H2I.
- Hydroxide ions. OH-.
- 40 + 2(62) = 40 + 124 = 164
- When chemicals react, the atoms of the reactants swap places to make new compounds, which are the products. They do no disappear.
- 22g CO2
Fertilisers and crop yield & The Haber Process - Q
Fertilisers and crop yield
- What's the relative formula mass of ammonium phosphate, (NH4)3 PO4?
- Calculate the percentage of nitrogen in ammonium phosphate.
- Which acid and base react to make potassium phosphate.
- Suggest how a solid sample of potassium phosphate could be made. Outlining all the main stages.
The Haber process
- At what temperature is the Haber Process carried out?
- Why is this temperature chosen?
- Why is a low pressure not used in the Haber Process?
- High pressure gives the highest yield in the Haber Process, but it's not used. Explain why.
Fertilisers and crop yield & The Haber Process - A
- 42/149 x 100 = 28%
- Potassium hydroxide and phosphoric acid.
- Titrate the potassium hydroxide with phosphoric acid, using an indicator. Repeat the titration until three consistent results are obtained. Use the titration result to add the correct amounts of acid and alkali together, without the indicator. Evaporate most of the water using a hot water bath. Leave the remaining solution to crystallise, then filter off the crystals.
The Haber Process
- About 450 oC
- The yield is lower, the the rate of production is higher.
- The yield would be too low.
- A lower, optimum temperature is chosen to give a reasonable yield/cost.
Detergents & Batch or continuous? - Questions
- What are the two reactants used in making a detergent?
- What does the hydrophobic tail of the detergent dissolve?
- Give two reasons why a dry-cleaning methods may be used.
- Which intermolecular forces are stronger: Grease-water or water:water?
Batch or continuous?
- What's a batch process?
- Write down one advantage of using a continuous process.
- Give two reasons why medicines are expensive to develop.
- How long can it take to research, develop, test and patent a new drug?
Detergents & Batch or continuous? - Answers
- An organic acid and an alkali.
- The oil.
- Fabrics may be damaged by washing in water and grease stains do not dissolve in water but do in dry-cleaning solvent.
- Water - water.
Batch or continuous?
- A batch process is where the whole process takes a limited time then stops and can be changed if necessary.
- The plant can be used to full capacity at all time.
- There are legal requirements, investment costs of its research and development, raw materials, labour intensive.
- Many years.
Nanochemistry & How pure is our water? - Questions
- Which properties of graphite make it useful as an electrode?
- Write down two potential uses of nanotubes.
- Explain why graphite can conduct electricity buy diamond can't.
- xplain one use of a fulleren as a cage.
How Pure is Our Water?
- Explain why filtration is used in the water purification process.
- Explain why distillation uses large amounts of energy.
- What type of reaction takes place between barium cholrife and sulfates?
- Write a balanced symbol equation for the reaction between silver nitrate solution and magnesium chloride, MgBr2.
Nanochemistry & How pure is our water? - Answers
- Conducts electricity and has a high melting point.
- semiconductors in electrical circuits, industrial catalysts, reinforce graphite for tennis rackets.
- Graphite has delocalised electrons that can move through the structure. Diamond does not.
- To trap or transport molecules.
How pure is our water ?
- Sand is used to filter out fine particles that do not sediment out.
- The water needs to be heated up to boiling point then cooled.
- 2AgNo + MgBr = 2AgBr + Mg(No3)