BIO CHAP 2

Which of the following particles are found in the nucleus of an atom?

protons and neutrons

Table salt is formed when

sodium donates its single outer electron to chlorine

Which of the following statements about pH is true?

An increase in hydrogen ion concentration means a decrease in pH scale units.

In the equation 2 H2 + O2 → 2 H2O,

only H2O is a compound.

The sodium atom contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium?

23

Which of the following statements best describes a compound?

A compound contains two or more different elements in a fixed ratio

The four most common elements in living organisms are

C, H, O, N.

How will a lower ocean pH caused by ocean acidification affect coral reefs?

Coral reefs will grow slower because there are fewer carbonate ions available.

The temperature of evaporation is much higher for water than for alcohol. Without knowing more about the chemistry of alcohol, which of the following is the most logical chemical explanation for this phenomenon?

Fewer hydrogen bonds form between alcohol molecules. As a result, less heat is needed for alcohol molecules to break away from solution and enter the air.

Which of the following statements about water is false?

Ice is denser than liquid water.

Which of the following would be considered a trace element in the human body?

Iron or Fe

For most atoms, a stable configuration of electrons is attained when the atom __________.

has a completely filled outermost shell

Radioactive isotopes

can be used in conjunction with PET scans to diagnose diseases.

A radioactive isotope is an isotope that

decays.

Positron-emission tomography (PET) is a technique that doctors may use to _____.

determine hot spots of metabolic activity

The levels of carbon dioxide are expected to _____ of our oceans.

increase and lower the pH

The following graphs represent the future projections from Part B. Drag the labels to their appropriate locations on the graphs.

y-axis (300-900): atmospheric CO2 (ppm)y-axis (7.6-8.2): oceanic pHx-axis (2030-2090): yearyellow line: optimisticpurple line: middle groundred line: pessimistic

The graphs from Part C are shown here. Can you interpret them? Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

1. In 2016, atmospheric CO2 was at 400 ppm, and oceanic pH was at 8.1. 2. Under the Optimistic scenario, CO2 concentrations in the atmosphere will increase but will remain under 600 ppm through 2090. 3. Under the Middle Ground scenario, CO2 concentrations in the atmosphere will get close to, but are not projected to exceed 700 ppm by 2090. 4. Under the Pessimistic scenario, CO2 concentrations in the atmosphere are projected to exceed 800 ppm by 2090. 5. Across all three scenarios, ocean pH falls below 8.0 by 2090. 6. From the information in the graphs, you can conclude that oceanic pH and atmospheric CO2 concentration are negatively (or inversely) correlated. 7. Although not reflected in this graph, you can infer that as atmospheric carbon dioxide increases, oceanic carbon dioxide concentrations also increase, suggesting that the two variables are positively (or directly) correlated.

A nutrition facts label from a fortified cereal states that in a single serving of cereal there is 8% of the percent daily value of the element phosphorous. The label also says that a single serving of cereal plus one-half cup of skim milk has 20% of the percent daily value of phosphorus. Which of the following statements is false?

A half-cup of skim milk contains twice as much phosphorus as a serving of cereal.

After reading the paragraph below, answer the question that follows.You've been experiencing acid indigestion lately, and you'd like a quick fix for the problem. You do a little research on the Internet and discover that your problem is caused by excess stomach acid. In the pharmacy aisles, however, you're having a little trouble deciding what to purchase to address the problem. At the pharmacy counter, the clerk recommends that you purchase PEPCID AC or Alka-Seltzer tablets.You hypothesize that a tablet of PEPCID AC can neutralize more stomach acid than a tablet of Alka-Seltzer. If you placed a tablet of each antacid in a beaker of acid at an initial pH of 2, which of the following experimental results would support your hypothesis?

After 1 hour, the pH of the solution in the PEPCID AC beaker was 9.2 and the pH of the solution in the Alka-Seltzer beaker was 8.3.

Which of the following statements regarding matter is false?

All matter exists in the form of compounds.

Uranium is a metallic element that is used in nuclear reactors and nuclear weapons. The vast majority of uranium found on Earth is in the form of uranium-238 (with an atomic number of 92), an isotope with a mass number of 238, while the uranium that is used for nuclear reactors and weapons is uranium-235, an isotope with a mass number of 235.In a certain type of nuclear reactor, uranium-238 can be converted to plutonium-239, another radioactive element (with an atomic number of 94) that can be used to power nuclear reactions. Which of the following statements regarding uranium-238 and plutonium-239 is false?

An atom of plutonium-239 contains one more proton than an atom of uranium-238.

The following graph shows the average pH of the ocean over the last 20 million years of Earth's history. What can be concluded from the graph? Select all that apply.

Average ocean pH has fluctuated over the millennia from just over 8.0 to about 8.3. In the last 20 million years of Earth's history, the average pH has never gone below 8.0.

The oceans play an important role in regulating the amount of carbon dioxide in the atmosphere by absorbing atmospheric CO2. Atmospheric CO2 reacts with seawater to produce carbonic acid, resulting in increased oceanic acidity (measured by lower pH values). In 2016, Earth's atmosphere broke a record that had stood for approximately 16 million years: atmospheric CO2 levels measured at or above 400 ppm for the entire year. This increase in CO2 from a pre-industrial level of 280 ppm has already had an impact on oceanic pH, which has declined from pH 8.2 to pH 8.1 over the same time period -- a 30% increase in acidity. Scientists are studying how atmospheric CO2 concentrations and oceanic pH may change in the future. In work supported by the U.S. Department of Energy, researchers Denis Pierrot, Ernie Lewis, and Douglas Wallace developed a model to show how atmospheric CO2 levels and oceanic pH may change under three different carbon emission scenarios: An optimistic scenario A middle ground scenario A pessimistic scenario How could this data be best represented graphically?

Line Graph

What happens to an atom if the electrons in the outer shell are altered?

The atom acquires different properties.

The tendency of water molecules to stick together is referred to as

cohesion.

Typically, nitrogen atoms are composed of electrons, protons, and neutrons. An isotope of nitrogen could

have more neutrons than the usual nitrogen atom

You've been experiencing acid indigestion lately, and you'd like a quick fix for the problem. You do a little research on the Internet and discover that your problem is caused by excess stomach acid. In the pharmacy aisles, however, you're having a little trouble deciding what to purchase to address the problem. At the pharmacy counter, the clerk recommends that you purchase PEPCID AC or Alka-Seltzer tablets.If you could check the pH of the recommended tablets, you would expect it to be

higher than 7.

Which of the following subatomic particles has appreciable mass and lacks a charge

neutron

Below is the structure of octane, the major component of gasoline. What type(s) of bond(s) is(are) found in a molecule of octane?

only nonpolar covalent bonds

The four most common elements in living organisms are

oxygen carbon hydrogen nitrogen

Generally, what determines the number and kinds of chemical bonds an element can make and the chemical reactivity of an element?

the number of electrons in its outer shell

Researchers studying the effects of toxic wastes knew that animals were poisoned by the heavy metal cadmium, but they wanted to know where cadmium accumulated in the body. They could find out by _____.

tracing the movement of cadmium isotopes in test animals

As explained in the GraphIt! activity, the way ocean acidification works is that atmospheric carbon dioxide reacts with seawater to produce carbonic acid, resulting in increased acidity (measured by lower pH values). The change in pH is due to the H+ ions released as the carbonic acid molecule dissociates, forming bicarbonate ions and H+ ions. Furthermore, the H+ ions combine with carbonate ions present in ocean water, forming more bicarbonate ions. In summary, excess carbon dioxide leads not only to lower pH, but also to lower carbonate levels and higher bicarbonate levels. The decrease in carbonate levels affects calcification rates for organisms that build their shells from calcium carbonate (CaCO3); less carbonate means less calcium carbonate can be formed. The following graph depicts the relationship between atmospheric carbon dioxide concentrations and calcification rates in corals.

Although not reflected in the graph, based on how ocean acidification works, the relationship between oceanic pH and coral reef calcification rates can be predicted to be positively (or directly) correlated. True Coral reef calcification rates are projected to steadily decline as atmospheric CO2 concentrations increase. True As atmospheric CO2 concentrations reach 560 ppm, or double the preindustrial level, the coral calcification rate is projected to be reduced by more than two-thirds from what it was at the preindustrial level. True The data in this graph could also be plotted as a pie chart. False Declining coral calcification rates suggests a decrease in the level of bicarbonates and an increase in the level of carbonates in seawater. False As atmospheric CO2 concentrations reach 840 ppm, or three times the preindustrial level, the calcification rate will be reduced to 30 mmol/m2/day. False

A diabetic, who does not utilize insulin properly, will metabolize fats instead of glucose. A condition called diabetic ketoacidosis is a common result of excessive fat metabolism, causing blood pH values of 7.1 or less (normal range is 7.35-7.45). What has happened to the blood pH and why

The pH is below normal (acidic) because the buffering capacity was exceeded.

Uranium is a metallic element that is used in nuclear reactors and nuclear weapons. The vast majority of uranium found on Earth is in the form of uranium-238, an isotope with a mass number of 238, while the uranium that is used for nuclear reactors and weapons is uranium-235, an isotope with a mass number of 235.What is the atomic difference between uranium-235 and uranium-238?

Uranium-235 has three fewer neutrons than uranium-238.

You've made a hot drink by dissolving a teaspoon of instant coffee and a teaspoon of sugar in a cup of hot water. Which of the following statements is true?

You've just prepared an aqueous solution.

Which of the following trace elements needed by humans is commonly added to table salt?

iodine

Medicines are often administered in pill form. In many cases, the active ingredient of the pill (the drug) is joined to another substance by ________. This forms a(n) ________, which is stable in the dry environment of a pill bottle but dissociates under the wet conditions of the digestive system to release the drug to the body.

ionic bonds; salt