1. ethene, c2h4, burns in oxygen according to the equation. in an experiment, 10cm3 of ethene was burnt in 50cm3 of oxygen.
c2h4 + 3o2 = 2co2 + 2h2o

i) calculate the volume of the oxygen gas remaining at the end of the reaction.
ii) calculate the volume of carbon dioxide produced.

2. what volume(in cm3) of 0.100mol/dm3 copper(ii) sulfate solution is required to react completely with a solution containing 0.0250 mol of sodium hydroxide?
cuso4 + 2naoh = cu(oh)2 + na2so4

What is the composition, in atom percent, of an alloy that consists of 4.5 wt% pb and 95.5 wt% sn? the atomic weights for pb and sn are 207.19 g/mol and 118.71 g/mol, respectively.(a) 2.6 at% pb and 97.4 at% sn(b) 7.6 at% pb and 92.4 at% sn(c)97.4 at% pb and 2.6 at% sn(d) 92.4 at% pb and 7.6 at% sn

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.

Nonpoint source pollution is difficult to control because it