First, find the total mass.
34.5 g + 18.2 g + 2.6 g = 55.3 g
Divide the mass of each element by total mass.
34.5 g / 55.3 g = .62 x 100 = 62% element a
18.2 g / 55.3 = .33 x 100 = 33% element b
2.6 g / 55.3 = .047 x 100 = 4.7% element c
Hope I helped!
Correct Question:
A chemist measures the enthalpy change ΔH during the following reaction: Fe(s) + 2HCl(g)-->FeCl2(s) + H2 ΔH=-157.0 kJ. Use this information to complete the table below. Round each of your answers to the nearest kJ/mol
Answer:
-314 kJ
+628 kJ
+157 kJ
Explanation:
The enthalpy change of a reaction measures the amount of heat that is lost or gained by it. If ΔH >0 the heat is gained, and the reaction is called endothermic, if ΔH<0, the heat is lost, and the reaction is called exothermic.
If the reaction is inverted, the value of ΔH is inverted too (the opposite endothermic reaction is exothermic), and if the reaction is multiplied by a constant, ΔH will be multiplied by it too.
1) 2Fe(s) + 4HCl --> 2FeCl2(s) + 2H2(g)
This reaction is the product of the given reaction by 2, so
ΔH = 2*(-157) = -314 kJ
2) 4FeCl2(s) + 4H2(g) --> 4Fe(s) + 8HCl(g)
This reaction is the inverted reaction given multiplied by 4, so
ΔH = 4*(157) = +628 kJ
3) FeCl2(s) + H2(g) --> Fe(s) + 2HCl
This reaction is the inverted reaction given, so
ΔH = +157 kJ
Answer:

Explanation:
A reaction is spontaneous at all temperatures by the following combinations:
=> A negative enthalpy change (
)
=> A positive entropy change (
)
See the attached file for more better understanding!
Answer:
c
Explanation:
plants decrease the levels of carbon dioxide in the atmosphere due to the process of photosynthesis