Answer:
a) 14.2 atm
b) 4.46 atm
c) 1.06 atm
Explanation:
For an ideal gas,
PV = nRT
P = pressure of the gas
V = volume occupied by the gas
n = number of moles of the gas
R = molar gas constant = 0.08206 L.atm/mol.K
T = temperature of the gas in Kelvin
a) For HF,
P =?, V = 2.5L, n = 1.35 moles, T = 320K
P = 1.35 × 0.08206 × 320/2.5
P = 14.2 atm
b) For NO₂
P =?, V = 4.75L, n = 0.86 moles, T = 300K
P = 0.86 × 0.08206 × 300/4.75
P = 4.46 atm
c) For CO₂
P =?, V = 5.5 × 10⁴ mL = 55L, n = 2.15 moles, T = 57°C = 330K
P = 2.15 × 0.08206 × 330/55
P = 1.06 atm
It included a picture of Vladimir Lenin
Via half-life equation we have:

Where the initial amount is 50 grams, half-life is 4 minutes, and time elapsed is 12 minutes. By plugging those values in we get:

There is 6.25 grams left of Ra-229 after 12 minutes.
Answer: 1.12 m
Explanation:
This situation is related to parabolic motion, hence we can use the following equations:
(1)
(2)
Where:
is the ball final height (when it hits the ground)
is the ball initial height
is the initial velocity
is the angle at which the ball was launched
is the time
is the acceleration due gravity
is the horizontal distance the ball travels
Rewriting (1) with the given values:
(3)
Multiplying all the eqquation by -1 and rearranging:
(4)
So, since we have a quadratic equation here (in the form of
, we will use the quadratic formula to find
:
(5)
Where
,
,
Substituting the known values and choosing the positive result of the equation, we have:
(6)
Now, substituting (6) in (2):
(7)
(8) This is the horizontal distance at which the ball hits the ground.