Hey there Sign in to join this conversationNew here? Join for free

More Chemistry Questions !

Announcements Posted on
    • Thread Starter
    • 0 followers
    Offline

    ReputationRep:
    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
    • 11 followers
    Offline

    ReputationRep:
    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
    • 0 followers
    Offline

    ReputationRep:
    (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

Reply

Submit reply

Register

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?

    this is what you'll be called on TSR

  2. this can't be left blank
    this email is already registered. Forgotten your password?

    never shared and never spammed

  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. By joining you agree to our Ts and Cs, privacy policy and site rules

  2. Slide the button to the right to create your account

    Slide to join now Processing…

Updated: April 16, 2012
New on TSR

Student crowdfunds degree

Graduate raises £26,000 online for Masters course

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