A sample of helium gas has a volume of 900. milliliters and a pressure of 2.50 atm at 298 K. what is the new pressure when the temperature is changed to 336K and the Volume is decreased to 450. milliliters?

a- 0.177
b- 14.1
c- 5.64
d- 4.43

To solve this problem, we can use the combined gas law, which states:

(P1 × V1) / (T1) = (P2 × V2) / (T2)

Where:
P1 = initial pressure
V1 = initial volume
T1 = initial temperature
P2 = final pressure
V2 = final volume
T2 = final temperature

Given:
P1 = 2.5 atm
V1 = 900 mL
T1 = 298 K
V2 = 450 mL
T2 = 336 K

Using the combined gas law, we can rearrange the formula to solve for P2:

(P2 × V2) / T2 = (P1 × V1) / T1

Now we substitute the given values:

(P2 × 450 mL) / 336 K = (2.5 atm × 900 mL) / 298 K

Next, we can cross-multiply and solve for P2:

(P2 × 450 mL × 298 K) = (2.5 atm × 900 mL × 336 K)

P2 = (2.5 atm × 900 mL × 336 K) / (450 mL × 298 K)

P2 = 4.43 atm

Therefore, the answer is d- 4.43 atm.

To solve this question, we will use the ideal gas law equation: PV = nRT.

Given:
Initial volume (V1) = 900 mL
Initial pressure (P1) = 2.50 atm
Initial temperature (T1) = 298 K

Final volume (V2) = 450 mL
Final temperature (T2) = 336 K

First, we need to find the number of moles (n) using the given data:
n = PV/RT

Substituting the initial values into the equation:
n1 = (2.50 atm * 900 mL) / (0.0821 L·atm/mol·K * 298 K)

Next, we need to find the new pressure (P2) using the number of moles (n), final volume (V2), and final temperature (T2):
P2 = n2RT2 / V2

Substituting the known values into the equation and using the previously found value of n1:
P2 = (n1 * 0.0821 L·atm/mol·K * 336 K) / (450 mL)

Now we can calculate P2 by plugging in the numbers:
P2 = (n1 * 0.0821 * 33.6) / 0.45

Finally, we can substitute n1 into the equation and solve for P2:
P2 = (PV1 / RT1) * 0.0821 * 33.6 / 0.45

After solving this equation, the value of P2 is approximately 4.43 atm.

Therefore, the correct answer is option d- 4.43.

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