John is a chemical engineer with a pharmaceutical company. He is trying to develop a drug that can be absorbed by the system in different rates. To that end, he conducted two experiments. In one case, he used lower concentrations of reactants, he called it case A. Then he used the same reactants in a higher concentration. He called it case B. Would case B have higher or lower rate of reactions than case A? Hint: Collision theory tells us that molecules need to collide in order for a reaction to take place. All else being equal, anything that increases the frequency of collisions would also increase the rate of reaction. One way to do this is to increase the concentrations of one or more of the reactants. Using a real world example, a busy freeway will experience much more frequent car collisions than a fairly empty neighborhood street. Similarly, forcing more randomly moving molecules into the same amount of space will cause an increased number of collisions over a given length of time, providing the reactants with more opportunities to transform into products.
Ans: higher

John just opened a coffee shop. He offers two types of coffee, coffee A and coffee B. In coffee A he mixes ingredients in hot water, but in coffee B he mixes ingredients in cold water. He also notices that his shop gets very busy in the morning, but during evening he doesn't have many customers. Would coffee B be faster or slower to make than coffee A? Hint: When the temperature of reactants is higher, the rate of the reaction is faster. At higher temperatures, particles of reactants have more energy, so they move faster. They are more likely to bump into one another and to collide with greater force. For example, when you fry an egg, turning up the heat causes the egg to cook faster. The same principle explains why storing food in a cold refrigerator reduces the rate at which food spoils (see Figure below ). Both food frying and food spoiling are chemical reactions that happen faster at higher temperatures.
Ans: slower

John was studying the history of dinosaurs. He found that dinosaurs were flourishing before 66 million years ago. He labeled it as era A. Then he found that there was a mass extinction around 66 million years ago. He labeled that time period as era B. John found it interesting that many species have evolved in the course of history. In which era extinction rate would be higher, era A or era B? Hint: Species go extinct constantly as environments change, as organisms compete for environmental niches, and as genetic mutation leads to the rise of new species from older ones. Occasionally biodiversity on Earth takes a hit in the form of a mass extinction in which the extinction rate is much higher than usual. A large extinction-event often represents an accumulation of smaller extinction- events that take place in a relatively brief period of time.The first known mass extinction in earth's history was the Great Oxygenation Event 2.4 billion years ago. That event led to the loss of most of the planet's obligate anaerobes. Researchers have identified five major extinction events in earth's history since:
Ans: era B

Two high school buddies, Dan and Bob, had very different lifestyles 30 years later. Dan made only healthy lifestyle choices, was vegan. Bob ate meat, cheese and didn't care about his health and didn't protect himself. Which man used less sunscreen, Dan or Bob? Hint: Making these healthy lifestyle choices can also help prevent some types of cancer. In addition, you can lower the risk of cancer by avoiding carcinogens , which are substances that cause cancer. For example, you can reduce your risk of lung cancer by not smoking. You can reduce your risk of skin cancer by using sunscreen. How to choose a sunscreen that offers the most protection is explained below ( Figure below ). Some people think that tanning beds are a safe way to get a tan. This is a myth. Tanning beds expose the skin to UV radiation. Any exposure to UV radiation increases the risk of skin cancer. It doesn't matter whether the radiation comes from tanning lamps or the sun.
Ans: Bob