3. Which of the following conditions would likely cause the activation energy to be high?

A.atoms are close together
B.the temperature is hot
C.atoms are not close together *
D.a catalyst is present

4. Which of the following materials will burn the fastest in open air?
A.a log, two feet in diameter
B.two logs, each one foot in diameter
C.a pile of small splinters made from a two-foot diameter log *
D.Both logs and the splinters will burn at the same rate

3.B or C...not sure
4.A I think...please help

Sorry I meant to put C for 4 not A

I think C for 3.

I agree with C for 4.
For 3, A, B, and D will make the reaction easier; therefore, any activation enegry needed would be low.

Thank you...

To determine which condition would likely cause the activation energy to be high (Question 3), let's consider the definition of activation energy. Activation energy is the minimum amount of energy required for a chemical reaction to occur. It represents the energy barrier that needs to be overcome for reactant molecules to transform into product molecules.

Option A states that the atoms are close together, which actually helps facilitate chemical reactions by increasing the likelihood of collisions between reactant molecules. Option B suggests a high temperature, which increases the kinetic energy of the molecules and can result in more collisions with sufficient energy to overcome the activation energy. Option D mentions the presence of a catalyst, which lowers the activation energy by providing an alternate reaction pathway.

Option C states that the atoms are not close together. In this case, the reactant molecules are far apart and have less probability of colliding frequently. Therefore, this option is correct, as the infrequent collisions between reactant molecules lead to a higher activation energy.

For Question 4, we need to determine which material will burn the fastest in open air. Combustion requires a supply of oxygen, heat, and fuel. The material that has the greatest surface area-to-volume ratio will burn the fastest, as it provides more surface area for oxygen to react with the fuel.

Option A describes a log that is two feet in diameter. Since the diameter is larger, the available surface area for oxygen to react with the log is relatively small compared to the volume of the log. Therefore, this option would burn slower compared to the others.

Option B describes two logs, each one foot in diameter. The total surface area available for combustion is larger for two logs, but it is still limited compared to the volume of the logs.

Option C describes small splinters made from a two-foot diameter log. These splinters have a significantly larger surface area compared to their volume. The increased surface area facilitates faster combustion as more oxygen can react with the fuel on the surface.

Therefore, the correct answer is option C, a pile of small splinters made from a two-foot diameter log, as it has the highest surface area-to-volume ratio and will burn the fastest in open air.