When marshmallows are toasted, a chemical change occurs. The sugar molecules in the marshmallow are being changed into carbon (1). Sugar can be changed into water molecules. ... The flame on stage - oxygen diffuses to the surface of the marshmallow from the surrounding air.

6 0

4 years ago

Name three complex molecules synthesized by plants

DiKsa [7]

Oxygen, glucose and starch
Oxygen and glucose are produced during photosynthesis. Glucose is then stored as starch.

Hope it helped!

3 0

3 years ago

Oxidation states of NaMnO4

k0ka [10]

I have written it out and explained it. I hope it helps! Here:

7 0

3 years ago

In a generic chemical reaction involving reactants A and B and products C and D, aA + bB → cC + dD, the standard enthalpy ΔH∘rxn

velikii [3]

Answer:

A. ΔH∘rxn = 21.9 KJ/mol

B. ΔH∘rxn = 103 KJ/mol

C. C2H5OH + 3O2 → 2CO2 + 3H2O

Explanation:

The standard reaction equation is given as:

aA + bB → cC + dD

Its standard enthalpy is given as:

ΔH∘rxn = cΔH∘f(C) + dΔH∘f(D) − aΔH∘f(A) − bΔH∘f(B)

Reaction given to us is:

H2O(l) + CCl4(l) → COCl2(g) + 2HCl(g)

So, its standard enthalpy will be:

ΔH∘rxn = (1)ΔH∘f(CoCl2 (g)) + (2)ΔH∘f(HCl(g)) − (1)ΔH∘f(H2O(l)) − (1)ΔH∘f(CCl4(l))

using the values from table:

ΔH∘rxn = - 218.8 KJ/mol + (2)(- 92.3 KJ/mol) - (- 285.8 KJ/mol) - (- 139.5 KJ/mol)

ΔH∘rxn = 21.9 KJ/mol

Reaction given to us is:

2A + B ⇌ 2C + 2D

So, its standard enthalpy will be:

ΔH∘rxn = (2)ΔH∘f(C) + (2)ΔH∘f(D) − (2)ΔH∘f(A) − (1)ΔH∘f(B)

using the values from table:

ΔH∘rxn = (2)181 KJ/mol + (2)(- 523 KJ/mol) - (2)(- 225 KJ/mol) - (- 337 KJ/mol)

ΔH∘rxn = 103 KJ/mol

Balanced equation for combustion of ethanol is:

C2H5OH + 3O2 → 2CO2 + 3H2O

3 0

3 years ago