Question: I read this background article the other day: If a solution has a higher concentration of hydronium ions than pure water, it has a pH lower than 7. A solution with a pH lower than 7 is called an acid . As the hydronium ion concentration increases, the pH value decreases. Therefore, the more acidic a solution is, the lower its pH value is. Did you ever taste vinegar? Like other acids, it tastes sour. Stronger acids can be harmful to organisms. For example, stomach acid would eat through the stomach if it were not lined with a layer of mucus. Strong acids can also damage materials, even hard materials such as glass.  I am facing a new situation today: Mike is studying chemistry for his exam. Today, he is studying the properties of acids. He picks up an acid solution that he labels as solution A. To compare it with another solution he chooses a solution that is not an acid. He labels it as solution B.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which solution has more hydronium ions, sloution A or solution B?
Answer: solution A

Question: I read this background article the other day: Sometimes muscles and tendons get injured when a person starts doing an activity before they have warmed up properly. A warm up is a slow increase in the intensity of a physical activity that prepares muscles for an activity. Warming up increases the blood flow to the muscles and increases the heart rate. Warmed-up muscles and tendons are less likely to get injured. For example, before running or playing soccer, a person might jog slowly to warm muscles and increase their heart rate. Even elite athletes need to warm up ( Figure below ).  I am facing a new situation today: Two teams of athletes were attending a competition. Brown team arrived in time and started their warm up, but Green team arrived late and skipped their warm up so they experienced some people getting injured.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which team experienced an increased blood flow to the muscles?
Answer: Brown

Question: I read this background article the other day: Noble gases are also used to fill the glass tubes of lighted signs like the one in the Figure below . Although noble gases are chemically nonreactive, their electrons can be energized by sending an electric current through them. When this happens, the electrons jump to a higher energy level. When the electrons return to their original energy level, they give off energy as light. Different noble gases give off light of different colors. Neon gives off reddish-orange light, like the word “Open” in the sign below. Krypton gives off violet light and xenon gives off blue light.  I am facing a new situation today: A scientist named Kathy walks into her office to see two neon signs plugged into the wall and hanging above her desk. Confused, she looks around to see if there's any clue as to who put them there. Seeing nobody, she flips the light switch on and walks in. Upon flipping the light switch, only the large sign lights up. Even though they are clearly both plugged in, the small sign isn't turning on. Kathy leaves her office to find someone to ask who put these random signs up in her room.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Are the electrons in the small sign more or less energized than the large sign's electrons?
Answer:
less