Answer: The answer would be D.
Explanation: When a screw is tightened into an object, it is wedge in between.
A positive cahnge of enthalpy, ΔH rxn = + 55 kJ/mol, for the forward reaction means that the reaction is endothermic, i.e. the reactants absorb energy and the products are higher in energy.
Activation energy is the difference in the energy level of the reactants and the peak in the potential energy diagram (the energy of the transition state).
For an endothermic reaction, the products will be closer in energy to the transition state than what the reactans will be; so, the activation energy of the reversed reaction is lower than the activation energy of the forward reaction.
Activation energy of reverse and forward reactions is related by:
Activation energy of reverse rxn = Activation energy of forward rxn - ΔH rxn
=> Activiation energy of reverse rxn = 102 kJ/mol - 55 kJ/mol = 47 kJ/mol
Answer: 47 kJ/mol
#1: The element that loses electrons in a chemical reaction is said to have been which of the following?
A. reduced
B. oxidized
C. combusted
D. rusted
**idk, is it reduced or oxidized??
Answer: oxidized. The element that loses electrons increases its oxidation number (becomes more positve or less negative) and this is oxidation.
Which type of reaction occurs if one element gains electrons and another loses electrons?
A. combustion
B. synthesis
C. oxidation-reduction
D. double-displacement
**my answer: C
Yes, oxidation-reduction
#3: What is the oxidation number for phosphorus in H4P2O7?
A. +5
B. +3
C. +1
D. - 1
**my answer: A. +5
This is the way to calculate it 4(+1) + 2x + 7(-2) = 0 => x = +5
#4: What is the oxidation number for phosphorus in Na2HPO3?
A. +5
B. +3
C. +1
D. - 1
**my answer; B. +3
is that right??
Right
2(+1) + 1 + x + 3(-2) = 0 => x = 6 -1 -2 = 3 (positive)
