<span>The layer of rock above it might contain the fossil of a fish as, according to the law of faunal successsion, this was the first animal to evolve after shelled organisms. In sedimentary rock, animals that evolved later could only be found in layers above those from an earlier time.</span>
I am not fine..........................
Answer:
a. 82.68 g b. 9.8 min
Explanation:
a. The amount of gold deposited by 5 A current in 2 hrs 15 mins
Since charge Q = It where I = current = 5 A and time = 2 hrs 15 mins = 2 × 60 min + 15 min = 120 + 15 min = 135 min = 135 × 60 s = 8100 s
Q = 5 A × 8100 s
= 40500 C
Also, Q = nF where n = number of moles of gold deposited and F = Faraday's constant = 96500 C
n = Q/F = 40500 C/96500 C = 0.4195 moles ≅ 0.42 mole
Now n = m/M where m = mass of gold and M = molar mass of gold = 197
m = nM
= 0.42 × 197 g
= 82.68 g
b. The time taken for 6g of gold to be deposited.
We first find the number of moles of gold in 6g of gold
Since n = m/M and m = 6 g
n = 6/197 = 0.0305 mole
Q = It = nF
t = nF/I
= 0.0305 mol × 96500 C/5 A
= 2939.09 mol C
= 587.82 s
Changing t to minutes
587.82/60 s = 9.8 min
Answer:
density increases with more helium because of its molar mass
The reaction:
2 H 2 + O 2 → 2 H 2 O
2 Hydrogen molecules react with 1 Oxygen molecule to create 2 molecules of water.
We have to convert 53.8 g of Hydrogen into moles:
53.8 : 2.02 g / moles = 26.63 moles
2 moles H 2 ↔ 1 mole O 2
26.63 moles H 2 ↔ 13.32 moles O 2
Mass ( O 2 ) = 13.32 moles · 32 g/moles = 426.2 g
Answer: 426.2 grams of Oxygen.
