Question

1. water is always a product in what type of reaction?
2. what are the two products that are always formed in a combustion reaction?
3. when balancing a chemical reaction, what are the large numbers that we adjust?
4. when balancing a chemical reaction, what are the small numbers that we do not change?
5. according to the law of conservation of mass, can atoms be destroyed during a reaction? explain.

in the questions below, put a checkmark next to the equations that violate the law of conservation of mass. check each element

Explanation:

Question 26

In hydrocarbon combustion (e.g., burning fuels like methane, propane, or gasoline), the reaction is between a hydrocarbon (compound of C and H, sometimes with O) and oxygen ($O_2$). The products are always carbon dioxide ($CO_2$) and water ($H_2O$), as the hydrogen in the hydrocarbon combines with oxygen to form $H_2O$, and carbon combines with oxygen to form $CO_2$. For example, the combustion of methane: $CH_4 + 2O_2
ightarrow CO_2 + 2H_2O$.

Question 27

Combustion reactions involve a fuel (typically a hydrocarbon, like $CH_4$, $C_2H_5OH$, etc.) reacting with oxygen ($O_2$). The carbon in the fuel combines with $O_2$ to form $CO_2$, and the hydrogen in the fuel combines with $O_2$ to form $H_2O$. This is consistent across most hydrocarbon combustion reactions (e.g., burning wood, gasoline, natural gas). Even if the fuel has other elements, $CO_2$ and $H_2O$ are primary products (other products might form if impurities or other elements are present, but $CO_2$ and $H_2O$ are always there for hydrocarbon - oxygen combustion).

Question 28

In a chemical equation (e.g., $aA + bB
ightarrow cC + dD$), the coefficients ($a$, $b$, $c$, $d$) represent the number of moles (or molecules) of each substance. To balance the equation (ensure the same number of each atom on both sides), we change these coefficients. The subscripts (small numbers within the chemical formula, like the 2 in $H_2O$) cannot be changed, as they define the chemical identity of the compound (changing a subscript would make it a different compound). So the large numbers we adjust are the coefficients.

Question 29

Answer:

Water is always a product in a combustion reaction (specifically, hydrocarbon combustion, where hydrocarbons react with oxygen).