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CBDutyG
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I need any help I can get

Post by CBDutyG »

1. What mass of Silicium was dissolved in alkali if the volume of forming hydrogen is 2.24 l (n.c).








2. How much water and solution with mass part of ammonia 22 % are necessary for preparing of 300 g of ammonia solution with mass part 10 %.
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ChenBeier
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Re: I need any help I can get

Post by ChenBeier »

For the first one develop the chemical equation. How much hydrogen correspond to how much mole silicon.
From the given volume hydrogen you can calculate the mole of it and also themole of Si. The weight is then calcuĺated from this.

Number 2 refer to cross rule.

22 .....10 weight part
......10
0.........12 weight part

Summ is 22 weight part equal to 300 g
Need 10 weight part = 136,36 g of 22%. The rest is 12 weight parts 163,63 g water.
CBDutyG
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Re: I need any help I can get

Post by CBDutyG »

I don't get the first question still tbh but I do get the second one now thanks a bunch
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ChenBeier
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Re: I need any help I can get

Post by ChenBeier »

Develop

Si + 4 NaOH => Na4SiO4 + 2 H2
1 mol Si corresponds to 2 mol H2

2.24 l H2 was obtained . Convert this to mol . The half of the result will be the mole of silicon. Convert this to the mass.
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