Answer:
Scientific experiments need to be repeated so that scientists can make sure the results are as accurate as possible.
Explanation:
The point of a scientific experiment is to find the answer to a question. If a scientist performs an experiment only one time, they might find an answer to their question. However, they might have messed something up, so the answer is completely wrong. Doing an experiment momre than once can help a scientist make sure that their answer is correct. I hope this helps!
Answer is: C. The FDA tests give reliability to the results of improved health obtained by each company.
The FDA (The Food and Drug Administration) is a federal agency of the United States Department of Health and Human Services.
The FDA controls food safety, tobacco products, dietary supplements, prescription, pharmaceutical drugs, vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices, cosmetics and animal food.
The gas propellant will move "from a region of high pressure to a region of a lower pressure." Furthermore, the gas propellant is important in spray cans because it initiates movement of the fluid inside the can. When sprayed, the fluid will then disperse to a designated target.
Explanation:
1. Spontaneous as written at all temperatures
C. When ΔH is negative and ΔS is positive, the sign of ΔG will always be negative, and the reaction will be spontaneous at all temperatures.
2. Spontaneous in reverse at all temperatures
A. When ΔH is positive and ΔS is negative, the sign of ΔG will always be positive, and the reaction can never be spontaneous.
3. Spontaneous as written above a certain temperature
B. ΔH is positive and ΔS is positive - an endothermic reaction (positive ΔH) that also displays an increase in entropy (positive ΔS). It is the entropy term that favors the reaction. Therefore, as the temperature increases, the TΔS term in the Gibbs free energy equation will begin to predominate and ΔG will become negative.
4. Spontaneous as written below a certain temperature
D. ΔH negative and ΔS is negative - When the reaction is exothermic (negative ΔH) but undergoes a decrease in entropy (negative ΔS), it is the enthalpy term which favors the reaction. In this case, a spontaneous reaction is dependent upon the TΔS term being small relative to the ΔH term, so that ΔG is negative. The freezing of water is an example of this type of process. It is spontaneous only at a relatively low temperature.
