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Oksi-84 [34.3K]
3 years ago
7

Which classification best describes oxygen gas? a element b compound c solution d heterogeneous mixture

Chemistry
1 answer:
NNADVOKAT [17]3 years ago
4 0

Answer:

oxygen is an element because it is a pure substance which cannot be split into simpler substances by chemical means

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dusya [7]

Answer:

I think it is b.

Explanation:

8 0
3 years ago
Read 2 more answers
A 50/50 blend of engine coolant and water (by volume) is usually used in an automobile's engine cooling system. If a car's cooli
Diano4ka-milaya [45]

Answer:

\large \boxed{109.17 \, ^{\circ}\text{C}}

Explanation:

Data:

50/50 ethylene glycol (EG):water

V = 4.70 gal

ρ(EG) = 1.11 g/mL

ρ(water) = 0.988 g/mL

Calculations:

The formula for the boiling point elevation ΔTb is

\Delta T_{b} = iK_{b}b

i is the van’t Hoff factor —  the number of moles of particles you get from 1 mol of solute. For EG, i = 1.

1. Moles of EG

\rm n = 0.50 \times \text{4.70 gal} \times \dfrac{\text{3.785 L}}{\text{1  gal}} \times \dfrac{\text{1000 mL}}{\text{1 L}} \times \dfrac{\text{1.11 g}}{\text{1 mL}} \times \dfrac{\text{1 mol}}{\text{62.07 g}} = \text{159 mol}

2. Kilograms of water

m = 0.50 \times \text{4.70 gal} \times \dfrac{\text{3.785 L}}{\text{1  gal}} \times \dfrac{\text{998 g}}{\text{1 L}} \times \dfrac{\text{1 kg}}{\text{1000 g}} = \text{8.88 kg}

3. Molal concentration of EG

b =  \dfrac{\text{159 mol}}{\text{8.88 kg}} = \text{17.9 mol/kg}

4. Increase in boiling point

\rm \Delta T_{b} = iK_{b}b = 1 \times 0.512 \, \, ^{\circ}\text{C} \cdot kg \cdot mol^{-1} \, \times 17.9 \cdot mol \cdot kg^{-1} = 9.17 \, ^{\circ}\text{C}

5. Boiling point

\rm T_{b} = T_{b}^{\circ} + \Delta T_{b} = 100.00 \, ^{\circ}\text{C} + 9.17 \, ^{\circ}\text{C} = \mathbf{109.17 \, ^{\circ}C}\\\rm \text{The boiling point of the solution is $\large \boxed{\mathbf{109.17 \, ^{\circ}C}}$}

7 0
3 years ago
At a given temperature the vapor pressures of hexane and octane are 183 mmhg and 59.2 mmhg, respectively. Calculate the total va
Bas_tet [7]

Total vapor pressure can be calculated using partial vapor pressures and mole fraction as follows:

P=X_{A}P_{A}+X_{B}P_{B}

Here, X_{A} is mole fraction of A, X_{B} is mole fraction of B, P_{A} is partial pressure of A and P_{B} is partial pressure of B.

The mole fraction of A and B are related to each other as follows:

X_{A}+X_{B}=1

In this problem, A is hexane and B is octane, mole fraction of hexane is given 0.580 thus, mole fraction of octane can be calculated as follows:

X_{octane}=1-X_{hexane}=1-0.58=0.42

Partial pressure of hexane and octane is given 183 mmHg and 59.2 mmHg respectively.

Now, vapor pressure can be calculated as follows:

P=X_{hexane}P_{hexane}+X_{octane}P_{octane}

Putting the values,

P=(0.580)(183 mmHg)+(0.420)(59.2 mmHg)=131 mmHg

Therefore, total vapor pressure over the solution of hexane and octane is 131 mmHg.

4 0
3 years ago
Sodium hydroxide, NaOHNaOH; sodium phosphate, Na3PO4Na3PO4; and sodium nitrate, NaNO3NaNO3, are all common chemicals used in cle
nadya68 [22]

Answer:

NaOH > Na3PO4 > NaNO3

Explanation:

in NaOH

23/40 * 100 = 57.5%

in Na3PO4

3 * 23/164 * 100 = 42%

In NaNO3

23/85 * 100 = 27.1%

Hence;

NaOH > Na3PO4 > NaNO3

4 0
3 years ago
Find the value of x in the triangle
myrzilka [38]

Answer:

55.52°

Explanation:

Concept tested: Sine rule of triangles

We need to know the sine rule

  • According to sine rule, if the three sides of a triangle are a, b and c and the corresponding angles, A, B and C
  • Then, \frac{a}{SinA}=\frac{b}{SinB}=\frac{c}{SinC}

In this case;

  • If we take, a = 5.7 units and A = 70°, and

         b= 5 units, B = x°

  • Using the sine rule we can find the value of x

Therefore;

\frac{a}{SinA}=\frac{b}{SinB}

Then;

\frac{5.7}{Sin70}=\frac{5}{Sinx}

6.0658=\frac{5}{sinx}

Sinx=0.8243

Therefore, X = 55.52°

Therefore, the value of x in the triangle is 55.52°

6 0
3 years ago
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