Ammonia is a weak base because it produces ___ ions in solution
1 answer:
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Answer: The correct answer is: " 0.54 g " .
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Explanation:
Note that "hydrogen gas" is:
H₂ (g) ; that is: a "diatomic element" (diatomic gas) ;
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The molecular weight of "H" is: 1.00794 g ;
(From the Periodic Table of Elements).
So, the molecular weight of: H₂ (g) is:
" 1.00794 g * 2 = 2.01588 g ; {use calculator) ;
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Note the conversion for a gas at STP:
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1 mol of a gas = 22.4 L gas;
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i.e. " 1 mol / 22.4 L " ;
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So: " 5.7 L H₂ (g)
The "L" ("literes" cancel out to "1" ; since "L/L = 1 ;
The "mol" (moles) cancel out to "1" ; since "mol/mol = 1 ;
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and we are left with:
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[5.7 * 2.104588 g ] / 22.4 = ? g ;
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→ [ 11.9961516 g ] / 22.4 =
0.53554248214 g ;l
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We round this value to: " 0.54 g " ;
→ since "5.7 L " has 2 (two) significant figures;
22.4 is an exact number conversion;
and "5.7 L" has fewer significant figures than:
" 2.104588 " ; or: " 1.00794 " .
→ as such: We round to "2 (two) significant figures."
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Hope this is helpful. Wishing you the best in your academic endeavors!
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Answer:
600 g K₂SO₄
Explanation:
First write down the complete, balanced chemical equation for such question. In this case:
Cr₂(SO₄)₃ + 2K₃PO₄ → 3K₂SO₄ + 2CrPO₄
Next, calculate molar masses of required compounds mentioned in the question. In this case it is for Cr₂(SO₄)₃ and K₂SO₄.
- Molar mass(MM) of Cr₂(SO₄)₃:
= 2*(MM of Cr) + 3*( MM of S) + 3*4*( MM of O)
= 2*(52) + 3*(32) + 12*(16)
= 104 + 96 + 192
= 392 g
- Molar mass(MM) of K₂SO₄:
= 2*(MM of K) + 1*( MM of S) + 4*( MM of O)
= 2*(39) + 32 + 4*(16)
= 78 + 32 + 64
= 174 g
Here comes the concept of Limiting reagent:
The limiting reagent in a chemical reaction is the substance that is totally consumed when the chemical reaction is complete. The amount of product formed is limited by this reagent, since the reaction cannot continue without it. The other reactants present with this are usually in excess and called excess reactants. If quantities of both the reactants are given, then one should apply unitary method and find out the limiting reagent out of the two. Then, determine the amount of product formed or percentage yield.
Also, 1 mole( 392 g) of Cr₂(SO₄)₃ gives 3 moles( 174*3 = 522 g) of K₂SO₄.
Using unitary method, if 392g of Cr₂(SO₄)₃ gives 522 g of K₂SO₄ , then 450 g of Cr₂(SO₄)₃ will give how much of K₂SO₄?
Yeild of K₂SO₄ :
That is 599.3 g.
Since we have not considered molecular masses of individual atoms to 6 decimal places, this number can be approximated to 600g.
Therefore, 600g of K₂SO₄ is produced.