Problem: Background: Some materials have negative heats of solution; the dissolution of one of these solutes in water is an exothermic process. Heat is released, causing a net increase in the temperature of the solution. Conversely, other substances have positive heats of solution. For example, the dissolution of potassium nitrate in water is an endothermic process. The resulting absorption of energy causes the solution to become colder. Calculations involving heats of solutions follow the same basic approach that we have used with other enthalpy problems.  Paragraph: John is conducting an experiment in his chemistry lab. His goal is to find a chemical solution that can regulate temperature. To that end, he considered two processes, process A and process B. Process A is an exothermic process, but process B is an endothermic process.  Given the paragraph above, please answer correctly the following question: In which process the solution would be colder, process A or process B?

A: process B


Problem: Background: As time passes, the number of HIV copies keeps increasing, while the number of helper T cells keeps decreasing. The graph in Figure below shows how the number of T cells typically declines over a period of many years following the initial HIV infection. As the number of T cells decreases, so does the ability of the immune system to defend the body. As a result, an HIV-infected person develops frequent infections. Medicines can slow down the virus but not get rid of it, so there is no cure at present for HIV infections or AIDS. There also is no vaccine to immunize people against HIV infection, but scientists are working to develop one.  Paragraph: Robert and Justin are both patients in the hospital who are suffering complications from their HIV infections. The doctor is trying to get information from both men about their diseases so he can create customized treatment plans for both men. After a few questions, the doctor discovers that Robert has been infected with HIV for many years, while Justin's infection is quite recent.  Given the paragraph above, please answer correctly the following question: Who will have a more weakened immune system?

A: Robert


Problem: Background: However, when going across a period from left to right, the atomic radius actually tends to decrease. Why is this so? Each successive electron is going into the same principal energy level as the previous one, so the total amount of occupied space does not really go up significantly. Additionally, because protons are also added to the nucleus as you go across the row, the pull of the positively charged nucleus on the negatively charged electrons increases. This tighter pull leads to a slight decrease in atomic radius. As a result, the atomic radii of the elements exhibit a periodic trend, gradually tends to downward, but with a sharp spike up whenever electrons are added to a new principal energy level ( Figure below ).  Paragraph: There are two elements, Zaxon and Barton. Zaxon is an element that is further left on the period, and Barton is on the right of the period.  Given the paragraph above, please answer correctly the following question: Which element will have a larger atomic radius?

A: Zaxon


Problem: Background: Wildfire smoke contains particulate matter that may have adverse effects upon the human respiratory system. Evidence of the health effects of wildfire smoke should be relayed to the public so that exposure may be limited. Evidence of health effects can also be used to influence policy to promote positive health outcomes.Inhalation of smoke from a wildfire can be a health hazard. Wildfire smoke is composed of combustion products i.e. carbon dioxide, carbon monoxide, water vapor, particulate matter, organic chemicals, nitrogen oxides and other compounds. The principal health concern is the inhalation of particulate matter and carbon monoxide.Particulate matter (PM) is a type of air pollution made up of particles of dust and liquid droplets. They are characterized into three categories based on the diameter of the particle: coarse PM, fine PM, and ultrafine PM. Coarse particles are between 2.5 micrometers and 10 micrometers, fine particles measure 0.1 to 2.5 micrometers, and ultrafine particle are less than 0.1 micrometer.  Each size can enter the body through inhalation, but the PM impact on the body varies by size. Coarse particles are filtered by the upper airways and these particles can accumulate and cause pulmonary inflammation. This can result in eye and sinus irritation as well as sore throat and coughing. Coarse PM is often composed of materials that are heavier and more toxic that lead to short-term effects with stronger impact.Smaller particulate moves further into the respiratory system creating issues deep into the lungs and the bloodstream. In asthma patients, PM2.5 causes inflammation but also increases oxidative stress in the epithelial cells. These particulates also cause apoptosis and autophagy in lung epithelial cells. Both processes cause the cells to be damaged and impacts the cell function. This damage impacts those with respiratory conditions such as asthma where the lung tissues and function are already compromised. The third PM type is ultra-fine PM (UFP). UFP can enter the bloodstream...  Paragraph: Bobby and Sally are siblings that currently live in different cities. Bobby lives in a city that has wildfires on a regular basis. The local government is effective at combating these fires, but there are still quite a few over the course of a year. Sally lives somewhere that has never had a wildfire before, and she wasn't even aware they existed until her brother started talking about them.  Given the paragraph above, please answer correctly the following question: Who is less likely to experience eye irritation?

A: