An exothermic reaction causes the surroundings to:

• A. increase in temperature
• B. remain at the same temperature
• C. absorb heat from the system
• D. decrease in temperature

Answer: (A)

Verified step by step guidance

1. Understand the definition of an exothermic reaction: it is a chemical reaction that releases heat to its surroundings.
2. Recall that when heat is released by the system (the reacting substances), this heat is transferred to the surroundings.
3. Since the surroundings receive heat, their thermal energy increases, which typically causes an increase in temperature.
4. Analyze the options: 'increase in temperature' aligns with the surroundings gaining heat, while 'absorb heat from the system' is another way of saying the same but less direct about temperature change.
5. Conclude that the most direct and correct effect of an exothermic reaction on the surroundings is an increase in temperature.