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elena55 [62]
2 years ago
9

what volume of hydrogen gas is evolved from a reaction between 0.52 g of Na and water? This gas is collected at 20 C and 745mmHg

Chemistry
1 answer:
guapka [62]2 years ago
6 0
The  volume of  hydrogen  gas  that evolved  is   calculated  as  follows
by  use  of   ideal  gas  equation

that  is  PV = nRT
P=745  mm hg
V= ?
R(gas  constant)= 62.36 L.mm hg/mol.k
T= 20 + 273 = 293 k
n=number  of  moles which is calculated as  follows
find the  moles  of Na  used
= 0.52/23=0.023  moles

write the reacting equation
2Na +2H2O =2NaOH +H2
by  use  of reacting  ratio  between  Na : H2  which  is  2:1  therefore  the mole  of H2 = 0.023/2 =0.0115  moles

by  making  the  volume  the   subject  of  the formula
v=nRT/P
V= (0.0115 x 62.36  x 293) / 745  = 0.283 L


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PLEASE HELP!!!
trasher [3.6K]

Answer:

(a) oxygen

(b) 154g (to 3sf)

(c) 79.9% (to 3sf)

Explanation:

mass (g) = moles × Mr/Ar

note: eqn means chemical equation

(a)

moles of P = 84.1 ÷ 30.973 = 2.7152 moles

moles of O2 = 85÷2(16) = 2.65625 moles

Assuming all the moles of P is used up,

moles of O2 / moles of phosphorus = 5/4 (according to balanced chemical eqn)

moles of O2 required = 5/4 × 2.7152moles = 3.394 moles (more than supplied which is 2.65625moles)

therefore there is insufficient moles of O2 and the limiting reactant is oxygen.

(b)

moles of P2O5 produced

= 2/5 (according to eqn) × 2.7152

= 1.08608moles

mass of P2O5 produced

= 1.08608 × [ 2(30.973) + 5(16) ]

= 154.164g

= approx. 154g to 3 sig. fig.

(c)

% yield = actual/theoretical yield × 100%

= 123/154 × 100%

= 79.870%

= approx. 79.9% (to 3sf)

4 0
2 years ago
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Igoryamba
The correct answer for the question it is option  

>>>>D<<<<

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7 0
3 years ago
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hammer [34]

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Hope this helps!

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Answer:

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Explanation:

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