This is a question sent in by a student doing GCE O Level Chemistry Examination:
Hi. need some help for the following questions.
Q1) What other gases is present inside a chimney besides dust, sulphur dioxide and carbon dioxide? [2 marks]Ans: carbon monoxide, oxides of nitrogen. CORRECT?
Q2) Why must a litmus paper be moist when testing for gases? [1 mark]Ans: So that the gas can dissolve in water to form its H+ or OH- ions that determines its acidic/alkaline property. CORRECT?
Q3) What apparutus is best used to transfer 125cm3 of acid into a beaker? [1 mark]Ans: Pipette or burrete?
Q4) Why can’t a solution of copper (ii) oxide crystal be heated? Why must it be left evaporating and not heating? [1 mark]Ans: Because the crystals upon heating will decompose. CORRECT?
PS: Let’s us discuss on those questions above. You can leave your answers and suggested solutions in the “COMMENTS” section below.
I need help ASAP. i wanted to know that what apparatus names can be asked?
I want to read and get the papers
burette, caz’ thatz more accurate and can even give the reading in points.
in laboratories, mostly a burette is considered an appropriate instrument for adding acids.
basically.. it’s doing it 5 times instead of three .. and a burette is a much more accurate apparatus as compared to the pipette. The 25cm3 may be a little vague, resulting in a higher probability of having experimental errors 🙂
Ans: Pipette. There is 125cm3 pipette to transfer the acid (analyte, etc) into the beaker for acid-base titration.
Q3) What apparutus is best used to transfer 125cm3 of acid into a beaker? [1 mark]Ans: Pipette or burrete?
pipette can only measure up to 25cm3, or at most 50cm3 only. so i don’t think it’s possible to transfer it by pipette..
Answer for question3 is pipette. Cos pipette measures 25cm3 of liquid.
So if you want to measure 125 cm3, just do it 3 times using a pipette! =)
And the rest of the answers are correct! yay.hahaha