1)During an endothermic reaction, total energy

A. decreases.
B. increases.
C. stays the same.
D. cannot be determined.

2)The enthalpy of formation of an element is
A. negative.
B. positive.
C. zero.
D. negative or positive, depending on which element.

i think number 1 is A
for number 2 i marked C on my test, but i have mixed feelings that it could be D can you please help
Thank you

2 is C for sure.

#1 is not that easy I don't think. The question asks about total energy but provides only the fact it is endothermic. Endothermic tells you that the reaction absorbs heat from the surroundings in order to occur. It doesn't say anything about the total energy; i.e., nothing about delta S for you to calculate delta G.

1) Well, during an endothermic reaction, things are getting heated, quite literally! So, should total energy (which includes heat) decrease? Nah! It's actually quite the opposite. Total energy increases. So, B) increases is the correct answer here.

2) Ah, the enthalpy of formation! When an element forms, it's like welcoming a new addition to the family of chemicals. And just like any family, there are different personalities. Some elements have positive enthalpy of formation, some have negative, and some are zero. So, the correct answer is actually D) negative or positive, depending on which element we're talking about.

Hope that clears things up!

1) In an endothermic reaction, energy is absorbed from the surroundings, which means that the total energy of the system increases. Therefore, the correct answer is B. To determine this, you can recall that endothermic reactions involve the absorption of heat or energy, resulting in a higher overall energy state.

2) The enthalpy of formation of an element refers to the energy change that occurs when one mole of the element is formed from its constituent elements in their standard states. For elements in their standard states, the enthalpy of formation is defined as zero. Thus, the correct answer is C. To confirm this, you can refer to a reliable source or textbook that provides the enthalpy of formation values for different elements.

It is understandable to have mixed feelings or uncertainty when answering questions. However, it's important to rely on reliable sources, such as textbooks or reputable websites, to confirm the correct answers.

I believe that the answer to 1 is C because, according to the first law of thermodynamics, energy can be converted from one form to another but is neither created nor destroyed. So, the total energy of the universe would remain the same even if the system's energy decreases and the surrounding's energy increases. 2 is C.