Answer:
f = frequency = 590,000 Hz ===> 59×10^4 Hz
λ = Wavelength = ?
c = Speed of light in a vacuum = 3 × 10^8 m/s
** Hz = 1/sec
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Answer: 3.4 atm
Explanation:
Given that:
Volume of gas V = 5L
(since 1 liter = 1dm3
5L = 5dm3)
Temperature T = 0°C
Convert Celsius to Kelvin
(0°C + 273 = 273K)
Pressure P = ?
Number of moles of gas n = 0.75 moles
Note that Molar gas constant R is a constant with a value of 0.0821 atm dm3 K-1 mol-1
Then, apply ideal gas equation
pV = nRT
p x 5dm3 = 0.75 moles x (0.0821 atm dm3 K-1 mol-1 x 273K)
p x 5dm3 = 16.8 atm dm3
p = (16.8 atm dm3 / 5dm3)
p = 3.4 atm
Thus, a pressure of 3.4 atm is exerted by the gas.
Answer:
1.35 moles of O²⁻
21.6 grams of O²⁻
Explanation:
We know that the charge on Aluminium ion is +3 (i.e. Al³⁺) while, the charge on Oxide ion is -2 (i.e. O²⁻). Therefore, the overall neutral Al₂O₃ compound has 2 Al³⁺ ions and 3 O²⁻ ions. Since, we can say that,
1 mole of Al₂O3 contains = 3 moles of O²⁻ ions
So,
0.450 moles of Al₂O₃ will have = X g of O²⁻
Solving for X,
X = 0.450 mol × 3 mol ÷ 1 mol
X = 1.35 moles of O²⁻
As the mass of an atom is mainly due to the presence of protons and neutrons hence, the addition of two electrons (-ve 2 shows two gained electron) to Oxygen will make a negligible change to the atomic masss of Oxygen because electron is said to be almost 1800 times lighter than proton. Hence, the ionic mass of O²⁻ will be 16 g/mol and the mass of given moles is calculated as,
Mass = Moles × Ionic Mass
Mass = 1.35 mol × 16 g/mol
Mass = 21.6 g
Answer:
14.32g
Explanation:
Initial temperature = 83.8°C
Final temperature = 77.1°C
Temperature change, ΔT = 83.8°C - 77.1°C = 6.7
Heat, H = 167J
Specific heat, c = 1.740J/g °C
m = ?
All these parameters are related with the equation below;
H = mcΔT
m = H / cΔT
m = 167 / (1.740 * 6.7)
m = 167 / 11.658 = 14.32g