Why is light a wave?

Predict the sign of ΔSsys for each of the following processes. Which are positive? (a) Gasoline vapors mix with air in a car eng

OLEGan [10]

Answer:

Positive: a and b

Negative: c

Explanation:

The entropy (S) is the measure of the randomness of the system, and it intends to increase. The randomness can be determined by the energy of the molecules, their velocity and how distance they are between the other molecules.

When the entropy increases, ΔS is positive, when the entropy decreases, ΔS is negative. So, when gasoline mix with air in a car engine, the process intends to continue, the randomness increases and ΔS is positive. When hot air expands, the distance between the molecules increases, so ΔS is positive.

But, when humidity condenses, the molecules stay closer, so there's a decrease in the randomness, then ΔS is negative.

6 0

3 years ago

A 720. cm^3 vessel contains a mixture of Ar and Xe. If the mass of the gas mixture is 2.966 g at 25.0°C and the pressure is 760.

sleet_krkn [62]

Explanation:

The given data is as follows.

Pressure (P) = 760 torr = 1 atm

Volume (V) = $720 cm^{3}$ = 0.720 L

Temperature (T) = $25^{o}C$ = (25 + 273) K = 298 K

Using ideal gas equation, we will calculate the number of moles as follows.

PV = nRT

Total atoms present (n) = $\frac{PV}{RT}$

= $1 \times \frac{0.720 L}{0.0821 \times 298}$

= 0.0294 mol

Let us assume that there are x mol of Ar and y mol of Xe.

Hence, total number of moles will be as follows.

x + y = 0.0294

Also, 40x + 131y = 2.966

x = 0.0097 mol

y = (0.0294 - 0.0097)

= 0.0197 mol

Therefore, mole fraction will be calculated as follows.

Mol fraction of Xe = $\frac{y}{(x+y)}$

= $\frac{0.0197}{0.0294}$

= 0.67

Therefore, the mole fraction of Xe is 0.67.

6 0

3 years ago

If a lab requires each lab group to have 25ml of a solution and it takes 15 grams of CuNO3 to make 1 liter of solution how many

tino4ka555 [31]

We need to do some general algebra here.

We will find that you need 8.25 grams of CuNO₃ to make enough solution for the 22 labs.

We know that:

Each lab group needs 25 ml of solution.
it takes 15 g of CuNO₃ to make one L of that solution.
There are 22 labs.

Because each lab needs 25 ml of solution, 22 labs will need that amount 22 times, so the total amount of solution needed is:

22*25ml = 550 ml

Now we know that we need 15 grams to make one liter of solution, and:

1 L = 1000ml

Then you need 15g to make 1000ml

and x (we want to find this amount) to make 550ml

Then we can write two equations (not actual equations, as these are different units) like:

x = 550ml

15g = 1000ml

Now we can take the quotient between these two equations:

x/15 g = (550ml/1000ml)

And now we can solve this for x:

x = (550ml/1000ml)*15g = 8.25g

So you need 8.25 grams of CuNO₃ to make enough solution for the 22 labs.

If you want to learn more, you can read:

brainly.com/question/8743486

5 0

3 years ago

Convert 3.09 x 10~3 m = nm

Dmitriy789 [7]

3090000000nm

since there's 1m = 1000000000nm

6 0

4 years ago

238,2U --> 234Th + 90

stiv31 [10]

Answer:

$\\_{2}^{4} \alpha$

Explanation:

In this question, we wish to find the missing nuclei for the equation:

$\\_{92}^{238} U\rightarrow _{90}^{234} Th + _{Z}^{A} X$

In order to find the missing species, we need to use the charge and mass balance law. That is, the mass should be conserved: the total mass on the left-hand side with respect to the arrow should be equal to the total mass on the right-hand side with respect to the arrow:

$238 = 234 + A$