The activation energy Ea can be related to rate constant (k) at temperature (T) through the equation:
ln(k2/k1) = Ea/R[1/T1 - 1/T2]
where :
k1 is the rate constant at temperature T1
k2 is the rate constant at temperature T2
R = gas constant = 8.314 J/K-mol
Given data:
k1 = 0.543 s-1; T1 = 25 C = 25+273 = 298 K
k2 = 6.47 s-1; T = 47 C = 47+273 = 320 K
ln(6.47/0.543) = Ea/8.314 [1/298 - 1/320]
2.478 = 2.774 *10^-5 Ea
Ea = 0.8934*10^5 J = 89.3 kJ
Another name for a mesh screen is a sieve.
Answer:
Propane gas plus oxygen gas produces water and carbon dioxide.
Explanation:
This is the initial chemical equation: C3H8 + O2 = CO2 + H2O
This is the balanced chemical equation: C3H8 + 5 O2 = 3 CO2 + 4 H2O
Answer: The complete reaction is as follows.

Explanation:
When nucleus of two or more atoms are bombarded together then it leads to the formation of new particles with new identity. This type of reaction are called nuclear reaction.
For example, 
Here, nitrogen atom when bombarded with a neutron then it is forming hydrogen and a carbon atom.
As total atomic mass on reactant side is (14 + 1) = 15
So, the atomic mass of carbon formed on product side is (15 - 1) = 14.
The number of protons holded by this carbon atom is (7 - 1) = 6.
Therefore, we can conclude that the complete reaction is as follows.

4 elements are classified in group 4 like titanium, zirconium, hafnium and ruthorfordium