Burrows, tracks, coprolites, nests and footprints are examples of traces that can be found in a fossil.
Answer:
1) reduction
2) zero
Explanation:
Let us look at the definition of oxidation and reduction in a nutshell.
Oxidation is electron loss(oxidation number is increased)
Reduction is electron gain(oxidation number is decreased)
With the above definitions in mind let us look again at the equation in question 1:
Br2 + 2e- → 2Br-
We can see that the bromine molecule gained two electrons. Oxidation number decreased from zero on the left hand side of the reaction equation to -1 on the right hand side of the reaction equation hence the equation represents a reduction half equation.
For question 2, silver was displaced from its salt. On the left hand side of the reaction equation, silver had an oxidation number of +2. But remember than one of the riles for determining oxidation number of species is that the oxidation number of an uncombined element is zero. Hence, the oxidation number of silver element on the right hand side of the reaction equation is zero.
A should be the products and D should be the reactants. So D should be the answer.
Answer:
A
Explanation:
The entropy of a system has to deal with how energy is stored in a system. It tends to looks at the degree of disorderliness in the system.
The spontaneity of a reaction deals with the possibilities of the reactions occurring, while an exothermic reaction is one in which energy is released to the surroundings, the change in enthalpy here is negative.
The change in entropy or the change in enthalpy cannot dictate if a reaction is feasible I.e spontaneous or not. What determines the spontaneity of a chemical reaction is the change in free energy. For a reaction to be spontaneous, this value must be negative.
The change in free energy, the enthalpy and entropy are connected by the equation below:
ΔG = ΔH - TΔS
Now back to the question, for the first option, we were told that entropy increased and system is exothermic meaning negative enthalpy and positive entropy. In this case , change in free energy will be negative over all temperatures and hence, the reaction is spontaneous.
To the second option, we have negative entropy and negative enthalpy. Here change in free energy will only be negative at low temperature, which of course is not the best answer here
To the third option, we have negative entropy and positive enthalpy. This means change in free energy is only negative at high temperatures which of course is not the best answer.
Answer:
0.0002675 square km that's all (if you want it in feet just comment below this)
Explanation: