Answer:
P = 133.4 atm
Explanation:
Given data:
Mass of helium = 988 g
Volume = 45.0 L
Temperature = 23°C (23+273= 296 K)
Pressure of cylinder = ?
Solution:
Number of moles of helium:
Number of moles = mass/ molar mass
Number of moles = 988 g/ 4 g/mol
Number of moles = 247 mol
Pressure:
PV = nRT
P = nRT/V
P = 247 mol × 0.0821. atm. L/mol. K × 296 K / 45 L
P = 6002.5 / 45 L
P = 133.4 atm
Https://www.khanacademy.org/science/chemistry/chemical-reactions-stoichiome/stoichiometry-ideal/v/stoichiometry-example-problem-2 this should explain
Answer:
The distance in kilometer that Ted will go if he runs at the same pace for 285 minutes is 60km
Step-by-step explanation:
It was given that Ted Ted runs 20 km in 95 minutes, so for us to know how many kilometers he runs at the same pace for 285 minutes by using proportion.
For Ted to run 20 km in 95 minutes.

where given distance= 20km
Given time =95minutes
Speed=20/95 .............eqn(1)
To calculate the distance in kilometers Ted will go if he runs at the same pace for 285 minutes, then
Speed= K/225 ...............eqn(2)
Let us represent distance with 'K'
Given time 225minutes
Equating eqn(1) and eqn(2)
Hence the proportion model that Ted could use in modelling this situation is this;

Cross multiply
K×95=20×225

The distance in kilometer that Ted will go if
he runs at the same pace for 285 minutes is 60km