Data:
Arsenic Molar Mass = 74,9216 ≈ 75 u (<span>atomic mass unit)</span>
Solving:
1 mole of arsenic → 75g ------------ 6,02*10²³ molecules
..................................X -------------- 1 molecule
6,02*10²³X = 75
Answer:
B
Explanation:
The time it takes for half of the radioactive atoms to decay to a stable state.
Hope this helped!
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
Lead reacts very slowly with dilute hydrochloric acid to give lead chloride<span> and </span>hydrogen<span> gas. </span>
<span>lead + hydrochloric acid —> lead chloride + hydrogen
Pb(s) + 2HCl(aq) —> PbCl2(aq) + H2(g)</span>
<span>Lead reacts very slowly with dilute sulphuric acid to give </span>lead sulphate<span> and </span>hydrogen<span> gas. </span>
<span>lead + sulphuric acid —> lead sulphate + hydrogen
Pb(s) + H2SO4 (aq) —> PbSO4(aq) + H2(g)</span>
<span>Lead reacts very slowly with dilute nitric acid to give </span>lead nitrate<span> and </span>hydrogen<span> gas. </span>
<span>lead + nitric acid —> lead nitrate + hydrogen
Fe(s) + 2HNO3(aq) —> Fe(NO3)2(aq) + H2(g)</span><span> </span>
