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bogdanovich [222]
3 years ago
13

After you preform your experiment, you determine that the kf value for naphthalene is 6.91 °c/m . you are using 10g of naphthal

ene and added 1.0 g of your unknown. the the freezing point of the solvent decreased by 4.47 °c when the unknown was added. knowing this information, determine the molar mass of the unknown. g/mol
Chemistry
1 answer:
Masteriza [31]3 years ago
8 0
Answer is: molar mass of compound is 154,58 g/mol.<span>
m(</span>naphthalene<span>) = 10 g = 0,01 kg.
m(unknown compound) = 1,00 g.
</span>Δ<span>T (solution) = 4,47 °C.
Kf(</span>naphthalene) = 6,91°C/m<span>; cryoscopic constant.
M</span>(unknown compound) = Kf(naphthalene)· m(unknown compound) ÷ m(naphthalene)<span> · ΔT(solution).
M(xylene) = </span>6,91°C/m<span> · 1 g ÷ 0,01 kg · 4,47</span>°C<span>.
M(xylene) = 154,58 g/mol.</span>
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if 26.8g of copper (ll) chloride are dissolved in sufficient water to make 4.00 L of solution, what is the molarity of the solut
artcher [175]

Answer: Molarity of the solution is 4.97 \times 10^{-2} M and water is the solvent.

Explanation:

Given: Mass of solute = 26.8 g

Volume = 4.00 L

Now, moles of copper (II) chloride (molar mass = 134.45 g/mol) are calculated as follows.

No. of moles = \frac{mass}{molar mass}\\= \frac{26.8 g}{134.45 g/mol}\\= 0.199 mol

Molarity is the number of moles of a substance divided by volume of solution in liter.

Therefore, molarity of given solution is calculated as follows.

Molarity = \frac{no. of moles}{Volume (in L)}\\= \frac{0.199 mol}{4.00 L}\\= 0.04975 M\\= 4.97 \times 10^{-2} M

Solvent is defined as a component which is present in higher amount in a solution. Generally, a solvent is present in liquid state but it can also be a solid or gas.

In the given solution, copper (II) chloride is dissolved in water so copper (II) chloride is the solute and water is the solvent.

Thus, we can conclude that molarity of the solution is 4.97 \times 10^{-2} M and water is the solvent.

4 0
3 years ago
A chunk of ice breaks off a glacier and falls 30.0 m before it hits the water. Assuming it falls freely (there is no air resista
lina2011 [118]

Answer:

The ice chunk will take 2.47 seconds to hit the water.

Explanation:

Height from which ice chunk fell = h = 30.0 m

Initial velocity of the ice chunk = u = 0 m/s

Time taken by ice chunk to cover 30.0 m of height = t

Acceleration due to gravity = g 9.8m/s^2

Using second equation of motion ;

h=ut+\frac{1}{2}gt^2

30.0 m=0 m/s\times t+\frac{1}{2}\times 9.8 m/s^2\times t^2

t=\sqrt{\frac{30.0m/s\times 2}{9.8 m/s^2}}2.47 s

The ice chunk will take 2.47 seconds to hit the water.

7 0
3 years ago
Cars run on gasoline, where octane (C8H18) is the principle component. This combustion reaction is responsible for generating en
Bezzdna [24]

Answer:

  • 10.19 g CO₂
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Explanation:

The combustion reaction of Octane is:

  • C₈H₁₈ → 8CO₂ + 9H₂O

To calculate the mass of CO₂ and H₂O produced, we need to know the mass of octane combusted.

We calculate the mass of Octane from the given volume and density, using the following <em>conversion factors</em>:

  • 1 gallon = 3.785 L
  • 1 L = 1000 mL

Now we<u> convert 1.24 gallons to mL</u>:

  • 1.24 gallon * \frac{3.785L}{1gallon} *\frac{1000mL}{1L} = 4693.4 mL

We <u>calculate the mass of Octane</u>:

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Now we use the <em>stoichiometric ratios</em> and <em>molecular weights</em> to <u>calculate the mass of CO₂ and H₂O</u>:

  • CO₂ ⇒ 3.30 g Octane ÷ 114g/mol * \frac{8molCO_{2}}{1molOctane} * 44 g/mol =  10.19 g CO₂
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4 years ago
What is the difference in mean solar time between 30 N 75 W and 30 N 90 W​
ratelena [41]

Answer:

Every 15 degrees is an hour

Explanation:

What is the time difference in mean solar time between 30° N 75° W and 30° N 90° W?

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3 years ago
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I believe the balanced chemical equation is:

C6H12O6 (aq) + 6O2(g) ------> 6CO2(g) + 6H2O(l) 

 

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moles CO2 = 25.5 g C6H12O6 * (1 mol C6H12O6 / 180.15 g) * (6 mol CO2 / 1 mol C6H12O6)

moles CO2 = 0.8493 mol

 

Using PV = nRT from the ideal gas law:

<span>V = nRT  / P</span>

V = 0.8493 mol * 0.08205746 L atm / mol K * (37 + 273.15 K) / 0.970 atm

<span>V = 22.28 L</span>

6 0
3 years ago
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