Answer:
There are seven significant figures
Explanation:
There are seven different digits within the number. Three 0s, one 2, one 8, and two 3s, adding up to seven different numbers. You exclude the first 0 when the number is a decimal, leaving seven significant figures. Hope this makes sense! :)
Answer:
8 should be placed in front of SO₂.
Explanation:
The easiest way to solve this question is by writing the <u>entire</u> balanced equation:
4FeS₂ + 11O₂ -> 2Fe₂O₃ + 8SO₂
We can achieve this by first balancing the Fe, then S, and finally the O.
We can also double check our answer by counting the number of each element on both sides:
-Reactants: 4 Fe, 8 S, 22 O
-Products: 4 Fe 8 S, 22 O
Since they match, our equation is balanced, and the coefficient in front of SO₂ is 8.
Heat= mass * change in temperature* specific heat
specific heat=409 J/kg K
Answer:
T = 215.33 °C
Explanation:
The activation energy is given by the Arrhenius equation:

<u>Where:</u>
k: is the rate constant
A: is the frequency factor
Ea: is the activation energy
R: is the gas constant = 8.314 J/(K*mol)
T: is the temperature
We have for the uncatalyzed reaction:
Ea₁ = 70 kJ/mol
And for the catalyzed reaction:
Ea₂ = 42 kJ/mol
T₂ = 20 °C = 293 K
The frequency factor A is constant and the initial concentrations are the same.
Since the rate of the uncatalyzed reaction (k₁) is equal to the rate of the catalyzed reaction (k₂), we have:

(1)
By solving equation (1) for T₁ we have:
Therefore, we need to heat the solution at 215.33 °C so that the rate of the uncatalyzed reaction is equal to the rate of the catalyzed reaction.
I hope it helps you!