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lisov135 [29]
2 years ago
11

A solution is made by dissolving 9.74 g of sodium sulfate in water to a final volume of 165 mL of solution. What is the weight/w

eight % or percent by mass of the solute?
Chemistry
1 answer:
MatroZZZ [7]2 years ago
8 0

Answer: The weight/weight % or percent by mass of the solute is 5.41 %.

Explanation:

Mass of the sodium sulfate,w = 9.74 g

Volume of the water = 165 mL

Density of the water = 1 g/mL

Density=1 g/mL=\frac{\text{Mass of water}}{\text{Volume of water}}

Mass of the water =1 g/mL\times 165 mL=165 g

Mass of the solution, W:

Mass of solute + Mass of solvent =9.47 g + 165 g=174.47 g

w/w\%=\frac{w\times 100}{W}=\frac{9.45 g\times 100}{174.47 g}=5.41 \%

The weight/weight % or percent by mass of the solute is 5.41 %.


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Luden [163]

Answer:

The molar mass of the compound is:- 168.82 g/mol

The molar mass of the gas is:- 16.38 g/mol

Explanation:

(a)

Using ideal gas equation as:

PV=nRT

where,  

P is the pressure

V is the volume

n is the number of moles

T is the temperature  

R is Gas constant having value = 0.0821 L.atm/K.mol

Also,  

Moles = mass (m) / Molar mass (M)

Density (d)  = Mass (m) / Volume (V)

So, the ideal gas equation can be written as:

PM=dRt

Given that:-

Pressure = 20 kPa = 20000 Pa

The expression for the conversion of pressure in Pascal to pressure in atm is shown below:

P (Pa) = \frac {1}{101325} P (atm)

20000 Pa = \frac {20000}{101325} atm

Pressure = 0.1974 atm

Temperature = 330 K

d = 1.23 kg/m³ = 1.23 g/L

Molar mass = ?

Applying the equation as:

0.1974 atm × M = 1.23 g/L × 0.0821 L.atm/K.mol × 330 K

⇒M = 168.82 g/mol

<u>The molar mass of the compound is:- 168.82 g/mol</u>

(b)

Given that:

Pressure = 152 Torr

Temperature = 298 K

Volume = 250 cm³ = 0.25 L

Using ideal gas equation as:

PV=nRT

R = 62.3637\text{torr}mol^{-1}K^{-1}

Applying the equation as:

152 Torr × 0.25 L = n × 62.3637 L.torr/K.mol × 298 K

⇒n = 0.002045 moles

Given that :  

Mass of the gas = 33.5 mg = 0.0335 g

Molar mass = ?

The formula for the calculation of moles is shown below:

moles = \frac{Mass\ taken}{Molar\ mass}

Thus,

0.002045\ moles&#10;= \frac{0.0335\ g}{Molar\ mass}

<u>The molar mass of the gas is:- 16.38 g/mol</u>

5 0
2 years ago
If you compared 1 m solutions, was a 1 m nacl solution more or less hypertonic than a 1 m sucrose solution? what is your evidenc
igor_vitrenko [27]
When you say the solution is hypertonic, it means that the solution has a higher osmotic pressure. The formula for this is:

P = iMRT,
for strong electrolytes, i = number of ions. 
for nonelectrolytes, i = 1

1. The P for sucrose solution which is a nonelectrolyte (assuming room temp):
P = (1)(1m)(8.314 J/mol-K)(298 K)
P = 2477.572 Pa

The P for NaCl solution, which is a strong electrolyte:
P = (2)(1 m)(8.314)(298 K)
P = 4955.144 Pa

<em>So, that means that NaCl is more hypertonic than the sucrose solution.</em>

2. For the second question, the P for the combination of 1 m glucose (nonelectrolyte) and 1 m sucrose is:
P = (1)(1 m)(8.314)(298 K) + (1)(1)(8.314)(298 K) = 4955.144 Pa
<em>In this case, the osmotic pressures are now equal. It is not hypertonic, but isotonic.</em>

7 0
2 years ago
The terms motif (fold) and domain describe levels of protein organization more complicated than primary or secondary structure.
posledela

Answer:

Each specific property of motif and domain is explained.

Explanation:

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  • Unit of tertiary structure because alpha helix and beta sheets are units of secondary structure.
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Motif;

  • Repetetive supersecondary structure because they contain cluster of secondary structure.
  • Beta Alpha Beta unit is an example of motif
  • Clusters of secondary structure

Both Motif and Domain;

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8 0
2 years ago
The combustion of propane is best described as an
GalinKa [24]
<h3><u>Answer;</u></h3>

Exothermic chemical reaction

<h3><u>Explanation;</u></h3>
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  • Exothermic reactions give off energy, usually in the form of heat, while endothermic reactions absorb energy.
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5 0
2 years ago
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Furkat [3]
To answer this question, you just need to put all the variable into <span>PV = nRT formula. In this case, the pressure(P) is 2.5 atm, the number of molecule(n) is 1.3 mol, the temperature(T) is 22 celcius= 295.15 kelvin.
Then the volume should be:

</span><span>PV = nRT
</span>2.5 * V = 1.3 * <span>0.08206* 295.15
</span>V= 12.59L
4 0
2 years ago
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