Answer:
Explanation:
There is a trick to this. Counting out the 4 places is easy enough.
Start at the 8 and count to your right. You land on the nine, but that is not quite your answer.
The 7 influences the 9 and the nine gets bumped up which makes it a 10. but you just record the zero part. The 1 gets added to the 2.
That in turn influences the 2 which makes it a three. So your answer is
893.0
The trick is that you must include the 0. You are guaranteeing that you know the accuracy of the fourth place. Weird but true.
It helps just slight to convert this to scientific notation.
8.9297 * 10^2 = 8.930 * 10^2
You get the same rounding problem as discussed above, but it might be a little easier to see.
You get the same answer and you have to go through the same steps.
Answer:
mass of methanol = 519.3 g
Explanation:
Given data:
molecules of CH3OH = 9.77 × 10∧ 24
mass in gram = ?
Solution:
First of all we will calculate the number of moles:
(9.77 × 10∧ 24) × 1 mol / 6.02 × 10∧23 = 16.229 moles
Now we will calculate the mass in gram:
Formula:
number of moles = mass/ molar mass
16.229 mole = mass / 32 g/mol
mass = 16.229 mol × 32 g/ mol
mass = 519.3 g
Simple method:
molar mass of CH3OH is 32 g so according to Avogadro number,
32 g of CH3OH = 6.02 × 10∧23 molecules
9.77*10^24 molecules will be equal to
(32 g of CH3OH / 6.02 × 10∧23 molecules) × 9.77*10^24 molecules
= 5.136 × 10∧-23 g/molecules × 9.77*10^24 molecules
= 519.3 g
Answer: Thus the cell potential of an electrochemical cell is +0.28 V
Explanation:
The calculation of cell potential is done by :
Where both are standard reduction potentials.
As Reduction takes place easily if the standard reduction potential is higher(positive) and oxidation takes place easily if the standard reduction potential is less(more negative). Thus iron acts as anode and lead acts as cathode.
Thus the cell potential of an electrochemical cell is +0.28 V