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3 years ago

What is the mass of NaCl required to make 140 grams of a 12% solution of NaCl in water?

Chemistry

2 answers:

kobusy [5.1K]3 years ago

4 0

Answer:

mass of NaCl required = 17 grams

Explanation:

Mass% = mass of solute X 100 / total mass of solution

mass%= mass of solute X 100 / mass of solute + mass of solvent

given:

Mass of solution = 140 grams

mass % = 12%

Putting values

12 = mass of NaCl X 100 / 140

mass of NaCl = 12 X 140 /100 = 16.8 grams

mass of NaCl required = 17 grams

Makovka662 [10]3 years ago

3 0

Answer:

C. 17 grams.

Explanation:

∵ mass % = [mass of solute/mass of solution] x 100.

mass of solute (NaCl) = ??? g & mass of solution = 140.0 g.

<em>∴ mass of NaCl = (mass %)(mass of solution)/100 </em>= (12.0)(140.0)/100 = <em>16.80 g ≅ 17.0 g.</em>

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Using any data you can find in the ALEKS Data resource, calculate the equilibrium constant K at 30.0 °C for the following reacti

gayaneshka [121]

Answer : The value of $K$ for this reaction is, $2.6\times 10^{15}$

Explanation :

The given chemical reaction is:

$CH_3OH(g)+CO(g)\rightarrow HCH_3CO_2(g)$

Now we have to calculate value of $(\Delta G^o)$ .

$\Delta G^o=G_f_{product}-G_f_{reactant}$

$\Delta G^o=[n_{HCH_3CO_2(g)}\times \Delta G^0_{(HCH_3CO_2(g))}]-[n_{CH_3OH(g)}\times \Delta G^0_{(CH_3OH(g))}+n_{CO(g)}\times \Delta G^0_{(CO(g))}]$

where,

$\Delta G^o$ = Gibbs free energy of reaction = ?

n = number of moles

$\Delta G^0_{(HCH_3CO_2(g))}$ = -389.8 kJ/mol

$\Delta G^0_{(CH_3OH(g))}$ = -161.96 kJ/mol

$\Delta G^0_{(CO(g))}$ = -137.2 kJ/mol

Now put all the given values in this expression, we get:

$\Delta G^o=[1mole\times (-389.8kJ/mol)]-[1mole\times (-163.2kJ/mol)+1mole\times (-137.2kJ/mol)]$

$\Delta G^o=-89.4kJ/mol$

The relation between the equilibrium constant and standard Gibbs, free energy is:

$\Delta G^o=-RT\times \ln K$

where,

$\Delta G^o$ = standard Gibbs, free energy = -89.4 kJ/mol = -89400 J/mol

R = gas constant = 8.314 J/L.atm

T = temperature = $30.0^oC=273+30.0=303K$

$K$ = equilibrium constant = ?

Now put all the given values in this expression, we get:

$-89400J/mol=-(8.314J/L.atm)\times (303K)\times \ln K$

$K=2.6\times 10^{15}$

Thus, the value of $K$ for this reaction is, $2.6\times 10^{15}$

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3 years ago

What will happen if we put iron nails with sodium bicarbonate in a closed flask?

rjkz [21]

Answer:

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Explanation:

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