Questions asked by dragonflaring

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• 15g of copper(ii) chloride reacts with 20g of sodium nitrate. Calculate the mass of sodium chloride formed?
  
• How would I write an ionic equation to show the formation of ions from sulfur, calcium and arsenic?
  
• Joni finds an iron horseshoe and notices how it as a fine layer of red flaky material. On closer examination, it is a fine layer of rust. Given that the horseshoe is 430g, calculate the number of moles of pure iron the original horseshoe had?
  
• Aluminum oxide is decomposed to extract pure aluminum from the mineral. If 6.7 tons of aluminum oxide is mined, calculate the mass of pure aluminum produced?
  
• Write following electron transfer half equations: 1) Barium reacts with dilute nitric acid 2) Lithium reacts with dilute sulfuric acid?
  
• Predict why the refractive index of air is slightly higher than the refractive index of a vacuum?
  
• A brand new Rolls-Royce rolls off the back of a truck as it is beling delivered to tis owner. Full question in details?
  
• A car with a total mass of 1400kg (including occupants), traveling at 60kmh^-1 hits a large tree and stops in 0.08seconds. What is the magnitude of the deceleration of the 70kg driver of the car if he is wearing a properly fitted seat belt?
  
• Why, according to Newton's laws, can superman not fly?
  
• The cable holding an elevator would break if the tension in it exceeds 25000N. If the 480 kg elevator carries a load limit of 24 passengers (ave mass is 70kg per person) what is the max possible upward acceleration of the elevator without breaking cable?
  
• I need some help understanding how some ions have the same electronic arrangement as noble gasses? Like why does a Li+ ion has the same electron structure as helium or a Mg2+ ion has the same electron structure as a Na+ ion and an O2- ion?
  
• 30000 tonnes of a copper ore containing 6.5% chalcopyrite was mined. Calculate the theoretical yield of copper that could be extracted from this ore (in tonnes)?
  
• Solid zinc is placed in a solution of copper(II) ions. Solid copper forms and zinc ions are present in solution. I) Identify what type of reaction this is II) Write the net ionic equation for this reaction III) Write two electron transfer half equations?
  
• Hot air is blown into a balloon of mass 300 kg for it to descend at a constant acceleration of 3.0 ms^-2. What is the lift force exerted by the hot air on the balloon?
  
• Calculate the percentage yield of ferrous sulfide if 3 moles of iron produces 220 grams of ferrous sulfide?
  
• How much concentrated solution do you measure out and how much water do you need to add to make 500ml 0.1M HCl from 2M HCl?
  
• What is the molarity of a salt solution made by dissolving 240mg of NaCl in 4ml of water? Assume final volume is the same as the volume of water.
  
• Calcium chloride dissolves in water to form calcium and chloride ions, producing 83kJ of heat per mole. Calculate final temp. when 0.02 moles of calcium chloride is dissolved into 150ml of water at a temperature initially of 19 degrees?
  
• A solution is prepared by dissolving 10.8g ammonium sulphate in enough water to make 100ml of stock solution. A 10ml sample of this stock solution is added to 50ml of water. Calculate concentration of ammonium ions and sulphate ions in the final solution?
  
• Iron can be extracted from iron(III) oxide by heating it with coke (carbon). The other product in the extraction reaction is carbon dioxide. What mass of iron is produced by reacting 550g of iron(III) oxide with 60g of coke?
  
• Lithium metal will react readily with sulfuric acid. Which of the following is correct statement about the quantities of each reactant needed to produce the maximum amount of products without any reactant remaining?
  
• A 240 V electric kettle has a heating element with a resistance of 20 ohms. The kettle boils 750 ml water in 1.5 minutes. Assuming 100% efficiency, what was the initial temperature of the water just before the kettle was switched on?
  
• Explain the difference in the solubility of water and hydrogen sulfide in hexane? Solubility of water in hexane is 0.01 g/100g Solubility of hydrogen sulfide in hexane is 0.7g/100g?
  
• How many mL of a #"0.250 mol L"^(-1)# #"BaCl"_2# solution is required to precipitate all the sulfate ions from #"10.0 mL"# of a #"10.0 % (w/v)"# solution of #"Na"_2"SO"_4# ?
  
• 0.543g of CaCl2 was dissolved in enough water to make a 500ml solution. What is the concentration of Cl- in %w/v?
  
• From a laboratory on Earth, you observe a spacecraft traveling horizontally at a speed of 0.580 𝑐. You measure it to have a horizontal length of 5.80 𝑚 and a vertical height of 1.20 𝑚. What will be its length and height if it comes to rest in the lab?
  
• 34.6g of propane is initially at 0 degrees celsius and 100kPa. If the temp of the gas is accidentally raised to 25 degrees celsius, what mass of propane must be released in order for the volume occupied by the gas to remain constant?