When making a solution by diluting a stock solution. Suppose when a solid is stirred into a liquid and dissolves,
a homogenous mixture is formed. When the mixture does not dissolve, the mixture
is heterogeneous.
<h3><u>Answer;</u></h3>
- <u>0.433 g N2 </u>
- <u>0.293 g O2 </u>
- <u>0.0367 g He</u>
<h3><em>Explanation and solution;</em></h3>
- We can start by getting the total pressure; which will be the sum of the partial pressure of each gas.
221 torr + 131 torr + 131 torr
P (total) = 483 torr total
n = PV / RT, we can determine the total number of moles of the mixture
= (483 torr) x (1.30 L) / ((62.36367 L Torr/K mol) x (25.0 + 273.15 K))
= 0.033769 mol gases total
-
Therefore; we can determine the mass of each gas;
- <u>Nitrogen gas </u>
<em>N2 = 28.01 g/mol</em>
<em>= (0.033769 mol) x ( 221 torr N2/ 483 torr) x (28.01 g N2/mol) </em>
<u>= 0.433 g N2 </u>
<em>
O2 = 32 g/ mol </em>
<em> =(0.033769 mol) x (131 torr O2/ 483 torr) x (32 g O2/mol)</em>
<em> </em><em><u>= 0.293 g O2 </u></em>
- <em><u>Helium gas </u></em>
<em><u>
</u></em><em>He = 4 g/mol</em>
<em>= (0.033769 mol) x (131 torr He/ 483 torr) x (4.00 g He/mol) </em>
<em><u>= 0.0367 g He</u></em>
Answer:
Explanation:
We need to use the formula for heat of vaporization.
Identify the variables.
- The heat absorbed by the evaporating water is the <u>latent heat of vaporization. </u>For water, that is 2260 Joules per gram.
- Q is the energy, in this problem, 50,000 Joules.
- m is the mass, which is unknown.
Substitute the values into the formula.
We want to find the mass. We must isolate the variable, m.
m is being multiplied by 2260 J/g. The inverse operation of multiplication is division. Divide both sides by 2260 J/g.
Divide. Note that the Joules (J) will cancel each other out.
Round to the nearest whole number. The 1 in the tenth place tells us to leave the number as is.
The mass is about 22 grams, so choice B is correct.
Answer:
colloid
Explanation:
A colloid is a mixture in which one substance of microscopically dispersed insoluble or soluble particles is suspended throughout another substance. Some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid.
Answer:
-105 kJ
Explanation:
The enthalpy change of a reaction is the sum of the energy of the bonds of the reactants and the products. The bonds at the reactants are being broken, so it's an endothermic reaction, so the bond energy must be positive.
The bonds at the products are being formed, so the process is exothermic, and the bond energy must be negative. There are being broken 1 N≡N bond and 3 H-H bonds, and are being formed 6 N-H bonds:
Reactants: 945 + 3*432 = 2241 kJ
Products: 6*(-391) = -2346 kJ
ΔH = 2241 - 2346
ΔH = -105 kJ