More Chemistry Questions !

    • Thread Starter

    If anyone could answer any of these questions and explain how you work them out it would be much appreciated :confused:

    1. When 3.6g of butanal (relative formula mass = 72) was burned, 134 KJ of energy of energy was released.

    From this result, what is the enthalpy of combustion, in KJ mol -1.

    a) -6.7
    b) +6.7
    c) -2680
    d) +2680

    2. 5g of copper is added to excess silver nitrate solution. The equation for the reaction that takes place is;

    Cu(s) + 2AgNO3(aq) ------> 2Ag(s) + Cu(NO3)2(aq)

    After some time, the solid present is filtrated off from the solution, washed with water, dried and weighed.

    The final mass of the solid will be
    a) less than 5g
    b) 5g
    c) 10g
    d) more than 10g

    3. Two identical samples of zinc were added to an excess of two solutions of sulphuric acid, concentrations 2 mol -1 and 1 mol -1 respectively.

    Which of the following would have been the same for the two samples?
    a) The total mass lost
    b) The total time for the reaction
    c) The initial reaction rate
    d) The average rate of evolution of gas

    4. It is now known that protons and neutrons are made up of small particles called quarks.
    Each proton and each neutron contains 3 quarks.
    What is the approximate number of quarks in 1g of carbon-12?
    a) 6 x 10 to the 23
    b) 9 x 10 to the 23
    c) 1.8 x 10 to the 24
    d) 2.16 x 10 to the 25

    Show us your attempts and then we'll help you. Just giving you the answers will not cause you to learn anything new.
    • Thread Starter

    (Original post by Ari Ben Canaan)
    Show us your attempts and then we'll help you. Just giving you the answers will not cause you to learn anything new.
    Why be so mean :/ :L Ok, I'll try
Write a reply… Reply
Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: April 16, 2012
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

What is your favourite day of the week
Applying to university
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.