A change in _____ means that a chemical reaction has occurred.
A) the energy and mass
B) the kinds of atoms involved
C) the properties and identity of the reacting substances
D) the energy and kinds of atoms of the reacting substances
C) the properties and identity of the reacting substances
___ can change as a chemical reaction occurs
increase reaction rate
Increasing the concentration of the reactants will increase the frequency of collisions between the two reactants. When collisions occur, they do not always result in a reaction (atoms misaligned or insufficient energy, etc.). Higher concentrations mean more collisions and more opportunities for reaction.
To determine the correct answer, we need to understand what a chemical reaction entails and what changes occur during a chemical reaction.
A chemical reaction is a process where the substances involved undergo a transformation, resulting in the formation of new substances with different properties and identities. During a chemical reaction, the bonds between atoms are broken, and new bonds are formed, leading to the rearrangement of atoms and the creation of new molecules.
Now let's consider each option to see which one aligns with the changes that occur during a chemical reaction:
A) The energy and mass: Energy changes can occur during a chemical reaction, but they are not indicative of whether a chemical reaction has occurred. Similarly, mass is conserved during a chemical reaction, so there is no change in overall mass. Therefore, this option does not fully capture the changes that signify a chemical reaction.
B) The kinds of atoms involved: This option is correct. During a chemical reaction, the atoms rearrange and new substances are formed. This means that the kinds of atoms involved in the reaction change. Therefore, this change in the kinds of atoms indicates that a chemical reaction has occurred.
C) The properties and identity of the reacting substances: This option is also correct. As mentioned earlier, a chemical reaction leads to the formation of new substances with different properties and identities. Therefore, this change in properties and identity signifies that a chemical reaction has taken place.
D) The energy and kinds of atoms of the reacting substances: Although the energy of the reacting substances can change during a chemical reaction, it is not the sole indicator of a chemical reaction. Furthermore, as discussed in option B, the kinds of atoms involved do change during a chemical reaction. Therefore, this option incorporates the correct change in kinds of atoms but does not encompass the complete set of changes in a chemical reaction.
Based on the above analysis, the correct answer is C) the properties and identity of the reacting substances.
From Google:
In a chemical change, the atoms in the reactants rearrange themselves and bond together differently to form one or more new products with different characteristics than the reactants. When a new substance is formed, the change is called a chemical change.