Problem: A chemist is working in the lab with two beakers, beaker R and beaker T, filled with identical solutions. In her experiment, she is going to pour one liquid into beaker R and the same amount of a different liquid into beaker T. After pouring the liquid into beaker R, there is no noticeable change. Pouring the liquid into beaker T, she observes a change in the liquid. Which beaker has a higher reaction rate? Hint: A catalyst works by providing a lower energy pathway from reactants to products. The use of a catalyst involves intermediate reactions which have lower activation complexes than the original reaction. On a simplified reaction energy diagram, this can be thought of as lowering the activation energy for a given transformation. If the activation energy of a reaction is decreased, more collisions will have enough energy to overcome this lower barrier, so the reactant-to-product transformation will occur more frequently. As a result, the overall reaction rate will be higher than for an identical reaction with a larger activation energy barrier.

A: beaker T

Problem: Research team Alpha learned about early human activities, from 200000 years ago, while team Gamma learned about late human activities, 40000 years ago to present times. Which team didn't learn about humans that lived in small populations of nomadic gatherers? Hint: The earliest members of the human species evolved around 200,000 years ago in Africa. Early humans lived in small populations of nomadic hunters and gatherers. Human beings remained in Africa until about 40,000 years ago. After that, they spread throughout Europe, Asia, and Australia. By 10,000 years ago, the first human beings colonized the Americas. During this long period of time, the total number of human beings increased very slowly. Birth rates were fairly high but so were death rates, producing low rates of population growth.

A: team Gamma

Problem: Two islands were located in the Pacific Ocean. Woo island was frequently shaken by earthquakes, but Mud island had no such problems. Which island experienced more stress building because of plates moving? Hint: Almost all earthquakes occur at plate boundaries. All types of plate boundaries have earthquakes. Convection within the Earth causes the plates to move. As the plates move, stresses build. When the stresses build too much, the rocks break. The break releases the energy that was stored in the rocks. The sudden release of energy creates an earthquake. During an earthquake the rocks usually move several centimeters or rarely as much as a few meters. Elastic rebound theory describes how earthquakes occur ( Figure below ).

A: Woo

Problem: Scientists are performing experiments on two different alkanes, Dipophane and Jothane. The scientists put each alkane into a beaker and begin heating each one at the same time to see which will melt first. During this experiment it is discovered that Dipophane melts before Jothane does. Which alkane will have a lower boiling point? Hint: Saturated hydrocarbons are given the general name of alkanes . The name of specific alkanes always ends in - ane . The first part of the name indicates how many carbon atoms each molecule of the alkane has. The smallest alkane is methane. It has just one carbon atom. The next largest is ethane, with two carbon atoms. The chemical formulas and properties of methane, ethane, and several other alkanes are listed in Table below . The boiling and melting points of alkanes are determined mainly by the number of carbon atoms they have. Alkanes with more carbon atoms generally have higher boiling and melting points.

A:
Dipophane