Gay Lussac’s of combining volumes states that gases react in simple ratio with one another and to volumes of the products provided that temperature and pressure remain constant. In this article, you will understand how to apply this law in calculation by studying the following examples below: 1. 2H 2 + O 2 → H 2 O In the reaction above, what volume of hydrogen would be left over when 300cm 3 of oxygen and hydrogen are exploded in a sealed tube? 1cm 3 of oxygen = 2cm 3 of hydrogen 300cm 3 of oxygen = 2 x 300 = 600cm 3 Volume of left over = 1000 – 600 = 400cm 3 2. Calculate the volume of carbon (II) oxide required to react with 40cm 3 of oxygen. 2CO + O 2 → 2CO 2 1cm 3 of oxygen = 2cm 3 of CO 40cm 3 of oxygen = 2 x 40 = 80cm 3 3. Calculate the volume of residual gases that would be produced when 100cm 3 of sulphur (IV) oxide reacts with 20cm 3 of oxygen 2SO 2 + O 2 → 2SO 3 1cm 3 of O 2 = 2cm 3 20cm 3 of O 2 = 2 x 20 = 40cm 3
A two-digit number is such that its tens digit is greater than its unit by 2. The two-digit number is more than 2 times the product of its digits by 23. Find the number Answer Let the two-digit number be = xy first statement x = (y+2) then xy = (y+2)y the product of the two-digit number = y(y+2) 10(y+2) +y = 2y(y+2)+23 10y +20+y = 2y 2 +4y +23 11y +20 = 2y 2 + 4y +23 2y 2 +4y +23 – 11y -20 2y 2 – 7y +3 =0 2y 2 -6y-y +3= 0 2y(y-3) -1(y-3) =0 (2y-1)(y-3) Y =1/2 or 3 X = (3+2) = 5 Xy =53 You can watch the video for more information and remember to subscribe for more free videos Thanks