Answer:
Option B. Single replacement reaction
Explanation:
To know which option is correct, it is important that we know the definition of each option. The definition of each option is given below:
1. Synthesis reaction is a reaction in which two different elements or compound combine together to produce a new compound different from the two starting elements or compound. An example is illustrated below:
C + D —> E
2. Single replacement reaction is a reaction in which an element replaces or displaces another element in a compound. An example is illustrated below:
D + BC —> B + CD
3. Combustion reaction is a reaction in a substance react with oxygen to generate carbon dioxide (CO₂) and water (H₂O). An example can be seen when organic compound react with oxygen to produce carbon dioxide (CO₂) and water (H₂O). This is illustrated below:
CₓHᵧ + (x + y/4) O₂ —> xCO₂ + (y/2) H₂O
4. Double replacement reaction is a reaction in which the ions of the two reacting compound replaces one another to form new products. This is illustrated below:
X⁺Y¯ + U⁺V¯ —> X⁺V¯ + U⁺Y¯
5. Decomposition reaction is a reaction in which a large compound breaks down into two or more elements or compound. An example is illustrated below:
GH —> G + H
Now, observing the equation given in the question above:
Sn + 2HCl —> SnCl₂ + H₂
We can see that Sn replaces H in HCl to produce SnCl₂.
Therefore, the reaction is a single replacement reaction.
I think what '13C' means is the isotope of carbon with mass number of 13. Its mass is 13 amu. The unit amu is equivalent to g/mol. The average atomic mass of Carbon is actually 12. But since we are solving for this particular isotope, we use a molar mass of 13 g/mol.
2 g C-13 * 1 mol/13 g = 0.154 moles of C-13
Answer: Endothermic reaction
Explanation:
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and 
for the reaction comes out to be negative.
Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and for the reaction comes out to be positive.
As the energy of reactants is 180 kJ and that of products is 300 kJ, the energy of products is greater than that of reactants, which means the energy has been absorbed and reaction is endothermic.
A. Testing a hypothesis
This leads to the other points
The 15th Amendment to the Constitution granted African American men the right to vote by declaring that the "right of citizens of the United States to vote shall not be denied or abridged by the United States or by any state on account of race, color, or previous condition of servitude."
