Answer:
C₈H₈O₃
Explanation:
The empirical formula is the simplest whole-number ratio of atoms in a compound.
The ratio of atoms is the same as the ratio of moles.
So, our job is to calculate the molar ratio of C:H:O.
Assume 100 g of the compound.
1. Calculate the mass of each element.
Then we have 63.15 g C, 5.30 g H, and 31.55 g O.
2. Calculate the moles of each element
3. Calculate the molar ratio of the elements
Divide each number by the smallest number of moles
C:H:O = 5.258:5.258:1.972 = 2.667:2.666:1
4. Multiply by a number to make each ratio close to an integer
Multiply the ratios by three.
2.667:2.666:1 = 8.000:8.000:3 ≈ 8:8:3
5. Write the empirical formula
EF = C₈H₈O₃
Equation for Half life :
A = a(0.5)^(t/h)
A is current amount, "a" is initial amount, h is halflife, t is time
5 = 40(0.5)^(t/1.3x10^9)
5/40 = (0.5)^(t/1.3x10^9)
take the log of both sides , power rule
Log(5/40) = (t/1.3x10^9) * Log(0.5)
(1.3x10^9) * Log(5/40) / Log(0.5) = t
3.9x10^9 years = t
And if you think about what a half life is, the time it take for the amount to reduce to half.
40/2 = 20
20/2 = 10
10/2 = 5
It went through 3 half-lifes
3 * 1.3x10^9 = 3.9x10^9 years
Don't know sorry the answer.
'Acceleration' means any change in speed or direction
of motion.
so
C). No acceleration. Straight, at constant speed.
No change of speed or direction.
Answer:
The correct answer is KNO3
Explanation:
Pb(NO3)2 +2 KCl -> PbCl2 + KNO3
If we look at the left side of the equation we could see that there are 1 lead atom, 2 nitrate atoms ,2 potassium atoms and 2 chlorine atoms
Now when we look at the right side of the equation, we found that there are –
1 lead atom and 2 chlorine atoms (PbCl2) , thus lead and chlorine are balanced as they have the same number of atom in LHS and RHS
There is only 1 potassium and 1 nitrate atom on RHS , thus KNO3 is not balanced.
The balanced equation would be –
Pb(NO3)2 +2 KCl -> PbCl2 +2 KNO3