<span>The choices are as follows:
h2o + 2o2 = h2o2
fe2o3 + 3h2 = 2fe + 3h2o
al + 3br2 = albr3
caco3 = </span><span>cao + co2
The correct answers would be the second and the last option. The equations that are correctly balanced are:
</span> fe2o3 + 3h2 = 2fe + 3h2o
caco3 = cao + co2
To balance, it should be that the number of atoms of each element in the reactant and the product side is equal.
Answer:
7.35atm
Explanation:
Data obtained from the question include:
V1 = 28L
T1 = 42°C = 42 + 273 = 315K
P1 =?
V2 = 49L
T2 = 27°C = 27 + 273 = 300K
P2 = 4atm
Using P1V1/T1 = P2V2/T2, the original pressure can be obtained as follows:
P1V1/T1 = P2V2/T2
P1 x 28/315 = 4 x 49/300
Cross multiply to express in linear form
P1 x 28 x 300 = 315 x 4 x 49
Divide both side by 28 x 300
P1 = (315 x 4 x 49) /(28 x 300)
P1 = 7.35atm
Therefore, the original pressure is 7.35atm
Answer:
fundamental frequency in helium = 729.8 Hz
Explanation:
Fundamental frequency of an ope tube/pipe = v/2L
where v is velocity of sound in air = 340 m/s; λ is wave length of wave = 2L ; L is length of the pipe
To find the length of the pipe,
frequency = velocity of sound / 2L
272 = 340 / 2 L
L = 0.625 m
If the pipe is filled with helium at the same temperature, the velocity of sound will change as well as the frequency of note produced since velocity is directly proportional to frequency of sound.
Also, the velocity of sound is inversely proportional to square root of molar mass of gas; v ∝ 1/√m
v₁/v₂ = √m₂/m₁
v₁ = velocity of sound in air, v₂ = velocity of sound in helium, m₁ = molar mass of air, m₂ = molar mass of helium
340 / v = √4 / 28.8
v₂ = 340 / 0. 3727
v₂ = 912.26 m /s
fundamental frequency in helium = v₂ / 2L
fundamental frequency in helium = 912.26 / (2 x 0.625)
fundamental frequency in helium = 729.8 Hz
