Well done! The slope of the line on the left is 2, because there are two moles of water produced for every mole of oxygen gas reacted. The slope of the line on the right is 1, because there is one mole of water produced for every mole of hydrogen gas reacted. This is true even though the coefficients for both water and hydrogen gas are 2. A 2:2 ratio is the same as a 1:1 ratio.