Chemistry + possible answers

for question 2c earlier - Would you describe the effect of heat on the white powders as a physical change or a chemical change? give one reason for your answer. - My sister told me the answer would be for whichever one is more difficult to reverse but I don't know which one that is. I think it might be a chemical change but if the actual substance didn't change than it should be easy to reverse right?

  1. πŸ‘ 0
  2. πŸ‘Ž 0
  3. πŸ‘ 54
asked by Moira
  1. The original post was a day or so ago and I don't remember all of the question. Have you identified the two white powders? If so, post that information and I can respond.

    1. πŸ‘ 0
    2. πŸ‘Ž 0
    posted by DrBob222
  2. Well I know the first two answers. 2a) was sublimination- turning directly from a solid to a gas and I worked out that 2b) was zinc oxide- it turned yellow on heating and white on cooling.

    1. πŸ‘ 0
    2. πŸ‘Ž 0
    posted by Moira
  3. Changing a solid to a gas by sublimation is a physical change because it was the same material before and after; i.e., the composition has not changed. I also think the ZnO is a physical change since the composition did not change. (Some oxides decompose on heating to give the metal + oxygen but I don't think ZnO is one of those).

    1. πŸ‘ 0
    2. πŸ‘Ž 0
    posted by DrBob222

Respond to this Question

First Name

Your Response

Similar Questions

  1. Read Y9 chemistry (then anwer this)

    2a) Someone finds teo bottles without labels. Both are white solids. One of the white solids turns directly from a solid to a gas on heating. What is this type of change called? b) The other solid turns yellow on heating. On

    asked by Moira on September 10, 2008
  2. chemistry

    describe how you would produce pure samples of iron and sulphur powders from a mixture of the two.

    asked by Natalia on February 11, 2010
  3. science

    Can anyone describe what this question means... Describe the big idea of in energy transfer in The Greenhouse effect

    asked by jack on December 9, 2007
  4. English

    I m doing an analysis question on a poem called Question by May Swenson. The question says: Describe the prosody of the poem and comment on the effect of the initial substitutions of the meter. I do not even know where to start

    asked by Amanda on March 2, 2014
  5. chemistry

    Posted a question earlier but it was the wrong question. If anyone could help it would great if you could explain this would help also. Thanks ^ = subscript Calculate ke for(equlibrium concentration below problem 2CO^2(g) + heat

    asked by Shanta on January 5, 2010
  6. Chemistry

    Experiment 10: Which Fuels provide the most heat? There are many possible sources of error in this experiment. List three that you can think of. Would each error have a large effect, a medium effect, or a small effect on the

    asked by Megan on October 7, 2010
  7. Chemistry

    I posted this question earlier but the person that answered did not include how to find the moles of the problem When 80.0 mL of HCl is added to 80.0 mL of NH3OH, the temperature increases 2.5 celsius. Assuming the final solution

    asked by Wendy on February 22, 2015
  8. English

    I Have No Idea What To Put For My Conclusion Of My Frankenstein Essay.... The Question For It Is Describe the significance of chapter five to the novel as a whole. Focus on the relevance and effect of the writer’s use of

    asked by Nicole:) on February 28, 2010
  9. Comp 156

    What is the definition of a cause and effect essay?Describe a cause and effect situation related to the effect of video games addiction on society.

    asked by Wonk on October 19, 2011
  10. Comp 156

    What is the definition of a cause and effect essay? Describe a cause and effect situation related to the effect of video games addiction on society

    asked by Wonk on October 17, 2011

More Similar Questions