The freezing point of a solution containing 5. 0 grams of KCl and 550.0 grams of water is - 0.45°C
Using the equation,
Δ
= i
m
where:
Δ
= change in freezing point (unknown)
i = Van't Hoff factor
= freezing point depression constant
m = molal concentration of the solution
Molality is expressed as the number of moles of the solute per kilogram of the solvent.
Molal concentration is as follows;
MM KCl = 74.55 g/mol
molal concentration =
molal concentration = 0.1219m
Now, putting in the values to the equtaion Δ
= i
m we get,
Δ
= 2 × 1.86 × 0.1219
Δ
= 0.4536°C
So, Δ
of solution is,
Δ
= 0.00°C - 0.45°C
Δ
= - 0.45°C
Therefore,freezing point of a solution containing 5. 0 grams of KCl and 550.0 grams of water is - 0.45°C
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Answer:
= 15.51 mL
Explanation:
Here's is the reaction:
2HgO(s) ⇒ 2 Hg(s)+O₂(g)
In this reaction 2mol HgO = 1mol O₂
The molecular weight of HgO = 216.59g
so, 3.0g HgO = 3.0g x 1.00molHgO/216.59gHgO
= 0.0138511 molHgO
The amount of Oxygen follows:
0.0138511 molHgOx1/2= 0.00692555 mol O₂
Now, volume of 1 any gas = 22400mL
so, 0.00692555 mol O₂ x22400mLO₂/1mol O₂
= 15.513232mL O₂
Neutralization reaction??
To work out the kinetic energy of an object, you use the formula:
E = 0.5 x (mass) x (velocity)^2
One important thing, though. The units MUST be consistent. Mass needs to be in kilograms, and velocity in metres per second.
To convert the mass form grams to kilograms, we need to divide it by 1000, getting 0.0103 kg. Since the velocity is already in the units we need, we can just plug the numbers into the equation to get:
E = 0.5 x (0.0103 kg) x (48.0)^2 = 11.8656 J = 11.9 J, to 3 significant figures
Hope I helped! xx