Question

10. How many moles of Ne are in a 0.50L tube at 200kPa and 50 °C? 11,60
​

Answer 1

0.04 mol Ne

General Formulas and Concepts:

Math

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Chemistry

Gas Laws

Combined Gas Law: PV = nRT

• P is pressure (in kPa)
• V is volume (in liters)
• n is amount of moles
• R is gas constant -
  `\displaystyle 8.314 (kPa \cdot L)/(mol \cdot K)`
• T is temperature (in Kelvins)

Step-by-step explanation:

Step 1: Define

P = 200 kPa

V = 0.50 L

T = 50°C

Step 2: Identify Conversions

Temperature Conversion: K = °C + 273.15

Step 3: Convert

1. Substitute T [TC]: K = 50°C = 273.15
2. Add: K = 323.15

Step 4: Find Moles

1. Substitute [CBL]:
   `\displaystyle (200 \ kPa)(0.50 \ L) = n(8.314 (kPa \cdot L)/(mol \cdot K) )(323.15 \ K)`
2. Multiply:
   `\displaystyle 100 \ kPa \cdot L = n(2686.67 (kPa \cdot L)/(mol))`
3. Isolate n:
   `\displaystyle 0.037221 \ mol = n_(Ne)`
4. Rewrite:
   `\displaystyle n_(Ne) = 0.037221 \ mol`

Step 5: Check

Follow sig fig rules and round. We are given 1 sig figs as our lowest.

0.037221 mol Ne ≈ 0.04 mol Ne