Answer:
Explanation:
Work function of potassium = 2.29 eV = 3.67 X 10⁻¹⁹ J
So the minimum energy of photon must be equal to 3.67 X 10⁻¹⁹ J .
energy of photon of wavelength λ = hc / λ
where h = 6.67 x 10⁻³⁴
c = 3 x 10⁸
Putting the values in the equation above
6.67 x 10⁻³⁴ x 3 x 10⁸ / λ = 3.67 X 10⁻¹⁹
λ = 6.67 x 10⁻³⁴ x 3 x 10⁸ / 3.67 X 10⁻¹⁹
= 5.452 x 10⁻⁷
= 5452 x 10⁻¹⁰ m
= 5452 A .
I don't know anything sorry for inconvenience but I will be used to make a system running with artificial intelligence
1) We apply the ideal gas equation:
PV = nRT
n = (21300 x 3/1000) / (8.314 x 323)
n = 0.024
Your answer is correct.
2) Total pressure = Partial pressure of Hydrogen + Partial pressure of water
134.7 = 122.4 + Pw
Pw = 12.3 kPa
Your answer is correct
3) The molar fraction, volume fraction and pressure fraction of gasses are the same thing.
Thus, percentage pressure of Oxygen = 10%
Pressure of Oxygen = 2.04 x 10⁴ x 0.1
= 2.04 x 10³ kPa
Your answer is correct
Well done!
Answer:
Volume of the sulfuric acid (25cm³), same mass of each metal (1g)
Explanation:
In an experiment, the CONTROL VARIABLE also known as constant is the variable that is kept unchanged for all groups in an experiment. This is done in order not to influence the outcome of the experiment.
In this case, students are trying to investigate the reactivity of four different metals. They added 1 g of each metal to 25cm³ of sulfuric acid and recorded the temperature change. Based on the explanation of control variable above, the VOLUME OF SULFURIC ACID (25cm³) and the MASS OF EACH METAL (1g) are the CONTROL VARIABLES because they are the same or unchanged in this experiment.
