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ivolga24 [154]
3 years ago
6

A student attempted to identify an unknown compound by the method used in the experiment. She found that when she heated the sam

ple weighing 0.4862g, the mass barely changed, dropping to 0.4855g. When the product was converted to a chloride, the mass went up to 0.5247g. Is the sample a carbonate? What are the two compounds that might be the unknown?
Chemistry
2 answers:
Brrunno [24]3 years ago
6 0

Answer:

The sample is a carbonate.

The unknown samples are Na2CO3 and K2CO3.

Explanation:

Let's assume ,the sample is Na2CO3.

Na2CO3 produces 2 moles of NaCl via formation of Na2O

Number of moles of NaCO3= 0.48262g/106gmol= 4.586×10^-3mol

Mass of NaCl= 2(4.586×10^-3)×58.5=0.536g

Let's assume the sample is K2CO3

K2CO3 produces2 moles of KCl

Number of moles of K2CO3= 0.4862g/138.21gmol

Number of moles= 3.517×10^-3mol

Mass of KCl formed= 2(3.517×10^-3)×74.55=0.5246g

yanalaym [24]3 years ago
3 0
Na2CO3 + 2Cl- ⇒ 2NaCl + CO3^-2 
<span>
1 mole of Na2CO3 = 106 g </span>
<span>2 moles of NaCl     = 2 x 58.4
                               = 116.8 g 
</span>Na2CO3 would increase by 116.8 / 106 = 1.10 to form 2NaCl.
<span>0.4862 g x 1.10 = 0.515 grams of NaCl.
</span>
K2CO3 + 2Cl- ⇒ 2KCl + CO3^-2 
<span>1 mole of K2CO3 = 138.2 g </span>
<span>2 moles of KCl = 149.1 </span>
<span>
K2CO3 would increase by </span>149.1 /138.2 = 1.079 <span>to form 2KCl
</span>
<span> 0.4862 x 1.079 = 0.5246 g</span>


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Explanation:

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3 years ago
Calculate the mass of sodium phosphate in aqueous solution to fully react with 37 g of chromium nitrate(III) an aqueous solution
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Answer:

41 g

Explanation:

The equation of the reaction is;

Cr(NO3)3(aq)+Na3PO4(aq)=3NaNO3(s)+CrPO4(aq)

Number of moles of chromium nitrate = 37g/ 146.97 g/mol = 0.25 moles

1 mole of sodium phosphate reacts with 1 mole of chromium nitrate

x moles of sodium phosphate react as with 0.25 moles of chromium nitrate

x= 1 × 0.25/1

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3 years ago
For the following reaction, 22.9 grams of nitrogen monoxide are allowed to react with 5.80 grams of hydrogen gas. nitrogen monox
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Answer:

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Explanation:

<u>The reaction </u>

2 NO (g) + 2 H_2 (g) \longrightarrow N_2 (g) + 2 H_2O (g)

Moles of nitrogen monoxide

Molecular weight: M_{NO}=30 g/mol

n_{NO}=\frac{m_{NO}}{M_{NO}}

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m_{N2}=0.763 mol NO* \frac{1 mol N_2}{2 mol NO}*\frac{28 g N_2}{mol N_2}

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3) <u>Ammount of excess reagent</u>:

m_{N2}=(2.9 mol - 0.763 mol NO* \frac{1 mol H_2}{1 mol NO})*\frac{2 g H_2}{mol H_2}

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