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30cm-3-of-hydrogen-at-s-t-p-combines-with-20cm-3-of-oxygen-to-form-steam-according-to-the-following-equation-2H-2-g-O-2-g-2H-2-O-g-Calculate-the-total-volume-of-gaseous-mixture-at-th




Question Number 18429 by tawa tawa last updated on 21/Jul/17
30cm^3  of hydrogen at s.t.p combines with 20cm^3  of oxygen to form steam   according to the following equation,  2H_2  (g) + O_2  (g) → 2H_2 O (g).  Calculate the total volume of gaseous mixture at the end of the reaction.
$$\mathrm{30cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{hydrogen}\:\mathrm{at}\:\mathrm{s}.\mathrm{t}.\mathrm{p}\:\mathrm{combines}\:\mathrm{with}\:\mathrm{20cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{oxygen}\:\mathrm{to}\:\mathrm{form}\:\mathrm{steam}\: \\ $$$$\mathrm{according}\:\mathrm{to}\:\mathrm{the}\:\mathrm{following}\:\mathrm{equation},\:\:\mathrm{2H}_{\mathrm{2}} \:\left(\mathrm{g}\right)\:+\:\mathrm{O}_{\mathrm{2}} \:\left(\mathrm{g}\right)\:\rightarrow\:\mathrm{2H}_{\mathrm{2}} \mathrm{O}\:\left(\mathrm{g}\right). \\ $$$$\mathrm{Calculate}\:\mathrm{the}\:\mathrm{total}\:\mathrm{volume}\:\mathrm{of}\:\mathrm{gaseous}\:\mathrm{mixture}\:\mathrm{at}\:\mathrm{the}\:\mathrm{end}\:\mathrm{of}\:\mathrm{the}\:\mathrm{reaction}. \\ $$
Commented by tawa tawa last updated on 21/Jul/17
Please help with workings
$$\mathrm{Please}\:\mathrm{help}\:\mathrm{with}\:\mathrm{workings} \\ $$
Commented by tawa tawa last updated on 21/Jul/17
I don′t know it sir
$$\mathrm{I}\:\mathrm{don}'\mathrm{t}\:\mathrm{know}\:\mathrm{it}\:\mathrm{sir} \\ $$
Commented by tawa tawa last updated on 21/Jul/17
Help me with the way you think it should be. God bless you sir.
$$\mathrm{Help}\:\mathrm{me}\:\mathrm{with}\:\mathrm{the}\:\mathrm{way}\:\mathrm{you}\:\mathrm{think}\:\mathrm{it}\:\mathrm{should}\:\mathrm{be}.\:\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir}. \\ $$
Commented by Tinkutara last updated on 21/Jul/17
1 cm^3  of O_2  requires 2 cm^3  of H_2 .  ∴ 20 cm^3  of O_2  requires 40 cm^3  of H_2 .  But available H_2  is only 30 cm^3 . Hence  it is the limiting reagent.  Now 2 cm^3  of H_2  produces 2 cm^3  of H_2 O.  ∴ 30 cm^3  of H_2  produces 30 cm^3  of H_2 O.  Volume of O_2  left unreacted = 5 cm^3   Hence final volume after the reaction  of is 35 cm^3 .
$$\mathrm{1}\:\mathrm{cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{O}_{\mathrm{2}} \:\mathrm{requires}\:\mathrm{2}\:\mathrm{cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{H}_{\mathrm{2}} . \\ $$$$\therefore\:\mathrm{20}\:\mathrm{cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{O}_{\mathrm{2}} \:\mathrm{requires}\:\mathrm{40}\:\mathrm{cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{H}_{\mathrm{2}} . \\ $$$$\mathrm{But}\:\mathrm{available}\:\mathrm{H}_{\mathrm{2}} \:\mathrm{is}\:\mathrm{only}\:\mathrm{30}\:\mathrm{cm}^{\mathrm{3}} .\:\mathrm{Hence} \\ $$$$\mathrm{it}\:\mathrm{is}\:\mathrm{the}\:\mathrm{limiting}\:\mathrm{reagent}. \\ $$$$\mathrm{Now}\:\mathrm{2}\:\mathrm{cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{H}_{\mathrm{2}} \:\mathrm{produces}\:\mathrm{2}\:\mathrm{cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{H}_{\mathrm{2}} \mathrm{O}. \\ $$$$\therefore\:\mathrm{30}\:\mathrm{cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{H}_{\mathrm{2}} \:\mathrm{produces}\:\mathrm{30}\:\mathrm{cm}^{\mathrm{3}} \:\mathrm{of}\:\mathrm{H}_{\mathrm{2}} \mathrm{O}. \\ $$$$\mathrm{Volume}\:\mathrm{of}\:\mathrm{O}_{\mathrm{2}} \:\mathrm{left}\:\mathrm{unreacted}\:=\:\mathrm{5}\:\mathrm{cm}^{\mathrm{3}} \\ $$$$\mathrm{Hence}\:\mathrm{final}\:\mathrm{volume}\:\mathrm{after}\:\mathrm{the}\:\mathrm{reaction} \\ $$$$\mathrm{of}\:\mathrm{is}\:\mathrm{35}\:\mathrm{cm}^{\mathrm{3}} . \\ $$
Commented by tawa tawa last updated on 21/Jul/17
God bless you sir.
$$\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir}. \\ $$
Commented by tawa tawa last updated on 23/Jul/17
The answer is correct sir.
$$\mathrm{The}\:\mathrm{answer}\:\mathrm{is}\:\mathrm{correct}\:\mathrm{sir}. \\ $$

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