Answer:
6.95 x 10²³ molecules/particles
Explanation:
First we need to find the total Empirical Mass. We can find this by adding each element's mass together.
Al = 26.982,
O = 15.999
H = 1.008
26.982 + 3(15.999) + 3(1.008) = 78.003.
Now we divide by the mass given (90 grams).
90/78.003 = 1.153801777.
We then take that number and multiply it by avogadro's number (6.022 x 10²³)
1.153801777 x avogadro's number = 6.95 x 10²³
Answer: PV = nRT
A gas at STP... This means that the temperature is 0°C and pressure is 1 atm.
R is the gas constant which is 0.08206 L*atm/(K*mol)
Rearranging for volume
V = nRT/P
The temperature and number of moles are held constant. This means that this uses Boyle's Law. (The ideal gas law could be manipulated to give us this result when T and n are held constant.)
PV = k
where k is a constant.
This means that
P₁V₁ = k = P₂V₂
P₁V₁ = P₂V₂
(1 atm) * (1 L) = (2 atm) * V₂
V₂ = 0.5 L
The new volume of the gas is 0.5 L.
Explanation:
The rate of photosynthesis was measured by counting the amount of oxygen, a product of photosynthesis, generated by the plant. When the plant placed closer to the light source in a given time it generated more bubbles than when it was placed farther away from the light source.
To determine which order of the reaction it is, first we need to calculate the rate of change of moles.
the data is as follows
time 0 40 80 120 160
moles 0.100 0.067 0.045 0.030 0.020
Q1)
for the first 40 s change of moles ;
= -d[A] / t
= - (0.067-0.100)/40s
= 8.25 x 10⁻⁴ mol/s
for the next 40 s
= -(0.045-0.067)/40
= 5.5 x 10⁻⁴ mol/s
the 40 s after that
= -(0.030-0.045)/40 s
= 3.75 x 10⁻⁴ mol/s
k - rate constant
and A is the only reactant that affects the rate of the reaction
rate = k [A]ᵇ
8.25 × 10⁻⁴ mol/s = k [0.100 mol]ᵇ ----1
5.5 x 10⁻⁴ mol/s = k [0.067 mol]ᵇ -----2
divide the 2nd equation by the 1st equation
1.5 = [1.49]ᵇ
b is almost equal to 1
Therefore this is a first order reaction
Q2)
to find out the rate constant(k), we have to first state the equation for a first order reaction.
rate = k[A]ᵇ
As A is the only reactant thats considered for the rate equation.
Since this is a first order reaction,
b = 1
therefore the reaction is
rate = k[A]
substituting the values,
8.25 x 10⁻⁴ mol/s = k [0.100 mol]
k = 8.25 x 10⁻⁴ mol/s /0.100mol
= 8.25 x 10⁻³ s⁻¹
