Answer: Option B) Pure Substance &
Compound
Explanation:
Carbon dioxide is a compound because it is formed when one carbon atom and two oxygen atoms chemically combined together.
C(s) + O2(g) ---> CO2(g)
Also, CO2 is a pure substance because it is natural and cannot be broken down easily or separated by physical methods.
Group 2 elements are the alkaline earth metals
I couldn't really find anything about the growth time but it does say that it could remain viable in soil for up to 40 years
Answer:
ΔH°_rxn = -195.9 kJ·mol⁻¹
Explanation:
4NH₃(g) + 3O₂(g) ⟶ 2N₂(g) +6H₂O(g)
ΔH°_f/(kJ·mol⁻¹): -45.9 0 0 -241.8
The formula relating ΔH°_rxn and enthalpies of formation (ΔH°_f) is
ΔH°_rxn = ΣΔH°_f(products) – ΣΔH°_f(reactants)
ΣΔH°_f(products) = -6(241.8) = -1450.8 kJ
ΣΔH°_f(reactants) = -4(45.9) = -183.6 kJ
ΔH°_rxn = (-1450.8 + 183.6) kJ = -1267.2 kJ
