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4 years ago

Determine the root-mean square speed of CO2 molecules that have an average kinetic energy of 4.2 x10-21 J per molecule.

1 answer:

8 0

<span>Determine the root-mean-square sped of CO2 molecules that have an average Kinetic Energy of 4.21x10^-21 J per molecule. Write your answer to 3 sig figs.
</span><span>
E = 1/2 m v^2

If you substitute into this formula, you will get out the root-mean-square speed.

If energy is Joules, the mass should be in kg, and the speed will be in m/s.

1 mol of CO2 is 44.0 g, or 4.40 x 10^1 g or 4.40 x 10^-2 kg.

If you divide this by Avagadro's constant, you will get the average mass of a CO2 molecule.

4.40 x 10^-2 kg / 6.02 x 10^23 = 7.31 x 10^-26 kg

So, if E = 1/2 mv^2

</span>v^2 = 2E/m = 2 (4.21x10^-21 J)/7.31 x 10^-26 kg = 115184.68
Take the square root of that, and you get the answer 339 m/s.

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Which instrument is most often used to measure acid volume before a titration begins?

Darya [45]

<span>Good Morning!

To measure the volume of an acid we use in the laboratory an instrument called burette (a). This instrument is used to calculate the volumes of chemical solutions. At first glance, these tools may be confused with syringes, but have different functions.

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4 0

4 years ago

Read 2 more answers

What is the value of k, at 25 degrees Celsius

Dimas [21]

<h3>Answer:</h3>

298.15 K

<h3>Explanation:</h3>

W e are supposed to calculate the Value of K at 25°C

Assuming the value of K represent K, the question wants us to convert degree Celsius to Kelvin.

To convert degrees Celsius to kelvin scale, we use the relationship;
Kelvin (K) = Degrees Celsius + 273.15 ; 273.5 is a constant
That is, to convert temperature from °C to Kelvin we add a constant of 273.15 to the °C given.

In this case;

Temperature is 273.15 °c

Thus, to Kelvin scale temperature will be;

= 25°C + 273.15

= 298.15 K

Therefore, the value of K, at 25°C is 298.15 K

7 0

3 years ago

When of alanine are dissolved in of a certain mystery liquid , the freezing point of the solution is less than the freezing poin

LenaWriter [7]

The question is incomplete, the complete question is:

When 177. g of alanine $(C_3H_7NO_2)$ are dissolved in 800.0 g of a certain mystery liquid X, the freezing point of the solution is $5.9^oC$ lower than the freezing point of pure X. On the other hand, when 177.0 g of potassium bromide are dissolved in the same mass of X, the freezing point of the solution is $7.2^oC$ lower than the freezing point of pure X. Calculate the van't Hoff factor for potassium bromide in X.

<u>Answer:</u> The van't Hoff factor for potassium bromide in X is 1.63

<u>Explanation:</u>

Depression in the freezing point is defined as the difference between the freezing point of the pure solvent and the freezing point of the solution.

The expression for the calculation of depression in freezing point is:

$\Delta T_f=i\times K_f\times m$

$\Delta T_f=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}$ ......(1)

<u>When alanine is dissolved in mystery liquid X:</u>

$\Delta T_f=5.9^oC$

i = Vant Hoff factor = 1 (for non-electrolytes)

$K_f$ = freezing point depression constant

$m_{solute}$ = Given mass of solute (alanine) = 177. g

$M_{solute}$ = Molar mass of solute (alanine) = 89 g/mol

$w_{solvent}$ = Mass of solvent = 800.0 g

Putting values in equation 1, we get:

$5.9=1\times K_f\times \frac{177\times 1000}{89\times 800}\\\\K_f=\frac{5.9\times 89\times 800}{1\times 177\times 1000}\\\\K_f=2.37^oC/m$

<u>When KBr is dissolved in mystery liquid X:</u>

$\Delta T_f=7.2^oC$

i = Vant Hoff factor = ?

$K_f$ = freezing point depression constant = $2.37^oC/m$

$m_{solute}$ = Given mass of solute (KBr) = 177. g

$M_{solute}$ = Molar mass of solute (KBr) = 119 g/mol

$w_{solvent}$ = Mass of solvent = 800.0 g

Putting values in equation 1, we get:

$7.2=i\times 2.37\times \frac{177\times 1000}{119\times 800}\\\\i=\frac{7.2\times 119\times 800}{2.37\times 177\times 1000}\\\\i=1.63$

Hence, the van't Hoff factor for potassium bromide in X is 1.63

7 0

3 years ago

In a varve, summer is represented by _____.

Tasya [4]

Answer:

sediment from melting glaciers being deposited in lakes

Explanation:

I took the test

5 0

3 years ago

PLZ HELP

poizon [28]

Answer:

Explanation:

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4 0

3 years ago