General Questions and Answers

△E Universe = △ESystem + △surroundings = 0 Where "E" is energy, the expression above is a representation of the law of - (A) equilibrium (B) conservation of mass (C) conservation of energy (D) definite composition

A student has a 5.00 gram sample of calcium chloride (CaCl2) solid. How many moles of calcium chloride are contained in this sample? A. 378 moles of CaCl₂ B. 0.0662 moles of CaCl₂ C. 555 moles of CaCl₂ D. 0.0451 moles of CaCl₂

You must show your calculations and answers must include correct units 1. You have a 525 g of Al2(CO3)3 (s). a. What is the molar mass of Al2(CO3)3? b. How many moles of Al2(CO3)3 (s) are in a sample with a mass of 525 grams?

In the early 1900s, what did it mean for cities to be dry" ? (a) Cities had severe water shortages and restricted water usage. (b) Cities imposed extremely high taxes on water usage. (c) Cities restricted the sale and consumption of alcohol. (d) Cities allowed consumption of alcohol as long as it was taxed.

Which best describes a strong research question for an informative essay? (A) A strong research question appeals to common knowledge, has a yes or no answer and can be discussed in several paragraphs. (B) A strong research question goes beyond common knowledge, has a yes or no answer and can be discussed in several paragraphs (C) A strong research question appeals to common knowledge, inspires curiosity and can be discussed in several paragraphs (D) A strong research question goes beyond common knowledge, inspires curiosity, and can be discussed in several paragraphs.

Which statement is the most effective claim? (A) Organic foods are a healthier option than conventional foods. (B) It is easier to find organic foods than to find conventional foods. (C) Restaurants are beginning to serve more organic foods. (D) Some think that organic foods are tastier than conventional foods.

An eflective chemotherapeutic agent for the treatment of tumor growths, N-nitrosomorpholine, has the empirical formula C2H4NO. If its molar mass is 112.1 g/mol, determine the molecular formula of the compound. (Enter the elements in the order: C, H, N, O.)

A student performed the experiment "Stoichiometry of a Precipitation Reaction" and obtained 120% yield of CaCO3. What is a possible explanation? Na2CO3 + CaCl2.2H2O--->CaCO3 + 2 NaCl + 2 H2O The student carried out the experiment carefully and accurately and thus obtained a high yield. The student unknowingly used CaCl2.9H2O instead of CaCl2.2H2O called for in the procedure. The precipitate CaCO3 was not completely dry when its weight was recorded. All of the above

The air pressure from the atmosphere measures 0.5 atm at an altitude of 18,000 ft. Calculate the air pressure in Ibs/in². Which of the following is correct? (A) 14.7 lbs/in² (B) 28 lbs/in² (C) 22 lbs/in² (D) 7.35 lbs/in²

Boron trifluoride gas is collected at - 18.0 °C in an evacuated flask with a measured volume of 45.0 L. When all the gas has been collected, the pressure in the flask is measured to be 0.460 atm. Calculate the mass and number of moles of boron trifluoride gas that were collected. Round your answer to 3 significant digits.

___Fe +3 O₂ → 2 Fe₂O₃ How many atoms of iron must react with 3 molecules of oxygen to form 2 molecules of iron oxide? (A) 4 (B) 2 (C) 1 (D) 3

Review: What is the Density (g/mL) of 1500 grams of solute (Calcium Chloride/CaCl2) added to 5000g of solution (water) that results in the solution having a volume of 7565 mL? (A) 0.85 g/mL (B) 0.19 g/mL (C) 0.66 g/mL (D) 1.16 g/ml

Explain the phenomenon of diffusion; Name the source of diffusion energy supply; Establish Fick's law; Explain the magnitudes of the diffusion coefficient; Give examples of diffusion in biological systems. Does the diffusion rate change during the diffusion process? Justify your answer.

Consider these reactions: Reaction 1: H2(g) + Cl2 (9) 2HCI(9) AH = -184.6 kJ Reaction 2: 20F2(g) + O2(g) + 2 F2(9) AH = –49.4 kJ Reaction 3: N2 (9) +202 (9) + 2NO2(g) AH = +66.4 kJ Use Reaction 2. How much energy (in kJ) is released when 52.0 g of oxygen difluoride decomposes? Answer: - _____ kJ (enter a positive value)

Choose the sentence that is capitalized correctly. "no country for Old men" won the Oscar for best picture in 2008. "No country for old men” won the Oscar for Best picture in 2008. No Country for Old Men won the Oscar for Best Picture in 2008.

Which of these factors did Spencer ignore in his theories of social Darwinism? (A) social variables that result in unequal opportunities (B) human ambition, which enables people to strive to succeed (C) competition within the human species that has parallels in nature (D) the desire of the human race to categorize others as winners or losers

An aqueous solution contains 5.0% hydrogen peroxide by mass. What is the molarity of this solution? (Assume a density of 1.02 g/mL.) Express your answer in moles per liter to two significant figures.

Name the following: 1. PO₃ 2. N₂H₄ 3. SO₃ 4. N₂O₃ 5. OF₂ Give formulas for the following. 6. Dichlorine octoxide 7. Dinitrogen tetroxide 8. Silicon carbide 9. Carbon dioxide 10. phosphorus trichloride

1) Using your knowledge of the Brønsted-Lowry theory of acids and bases, for the following acid-base reactions indicate each conjugate acid-base pair: a)HNO3 +OH^- --->NO3 + H2O b)CH3NH2 + H2O--->CH3NH3^+ + OH^- c)OH^- + HPO4^2- --->H2O + PO4^3-

During the Industrial Age, what was the main method that businesses used to inform consumers about new inventions they could purchase? (a) the multiplex (b)the telephone (c) the telegraph (d) advertisements

For each pair of reactants below, determine if a precipitate form or not. If "yes", write the formula for the precipitate; if "no" write no reaction. a) NaOH(aq) + FeBr₃ (aq): ▭ b) NaC₂H₃O₂ (aq) + Pb(NO₃)₂ (aq): ▭ c) BaCl₂ (aq) + AgNO₃ (aq): ▭

After World War II, the USSR extended its sphere of influence into Yugoslavia and Albania by (A) stationing troops there for many years. (B) appointing the head of state in each nation. (C) giving Soviet leaders local government jobs. (D) supporting the governments already in place.

What particles would be present in NH3(aq)? A) water molecules, NH4+ ions and OH- ions B) water molecules, H3O+ ions and NH₂ ions C) water molecules and NH3 molecules D) water molecules and NH3 molecules and a small number of NH4+ ions and OH- ions

How did President Bush respond to Hurricane Katrina? (a) He sent the United Nations to maintain order and arrest looters. (b) He visited crowded shelters to see conditions there for himself. (c) He sent US troops to help distribute supplies and repair damage. (d) He asked local officials to ascertain the extent of the damage.

What are alkaloids? Alkaloids are organic bases found in plants that are often poisonous. Alkaloids are inorganic bases found in plants that are good for health. Alkaloids are inorganic bases found in plants that are often poisonous. Alkaloids are organic bases found in plants that are good for health.

The government used a controversial bailout program to help (a) homeowners struggling with mortgages (b) foreign banks overloaded with debt. (c) automakers on the verge of collapse. (d) construction companies losing jobs.

A titration is performed with a weak base and strong acid. Which indicator from the chart provided would be BEST to use when determining the equivalence point of the solution? * (A) Bromocresol green (B) Bromothymol blue (C) Phenolphthalein (D) All of these would work

A chemist forms ammonium sulfate, (NH₄)₂SO₄, an excellent fertilizer, by combining ammonia (NH₃) and sulfuric acid (H₂SO₄). If she ends up making 12.5 moles of ammonium sulfate, how many moles of ammonia were used? 2NH₃ + H₂SO₄ → (NH₄)₂SO₄

Based on the periodic trend, arrange the following element in order of decreasing electronegativity. Highest Electronegativity (A) O (B) F (C) S (D) P (E) Sb Lowest Electronegativity

What is an acid-base neutralization reaction? (A) An acid-base neutralization reaction is when the hydroxide ion from the base reacts with water to form acid. (B) An acid-base neutralization reaction is when the hydroxide ion from the acid reacts with the hydrogen ion from the base to form water. (C) An acid-base neutralization reaction is when the hydroxide ion from the acid reacts with water to form base. (D) An acid-base neutralization reaction is when the hydrogen ion from the acid reacts with water to form base. (E) An acid-base neutralization reaction is when the hydrogen ion from the acid reacts with the hydroxide ion from the base to form water. (F) An acid-base neutralization reaction is when the hydrogen ion from the base reacts with water to form acid.

For the following reaction: 3Cu(s) + 8HNO₃(aq) → 3Cu(NO₃)₂(aq) + 2NO(g) + 4H₂O(l) (A) N is being reduced from +5 to +2 (B) Cu is being oxidized from 0 to -2 (C) N is oxidized from a +5 to +3 (D) Cu is being reduced and N is being oxidized (E) Cu is being reduced from 0 to -2

Combining______________ and _____________ is a double replacement reaction. Evidence: What did you see? Reasoning: SCIENCE! • Precipitate • Aqueous • Spectator ion • Net ionic equation

For the reaction H₂(g) + C₂H4(g) → C₂H6(g) a series of experiments were conducted as shown in the table. If the rate law was found to be rate = K[H₂][C₂H4], what is the missing initial rate (marked with the "?" in the table)? Initial rate (M/s) [H₂] [C₂H4] 0.0148 0.125 0.125 0.0301 0.250 0.125 ? 0.250 0.250 A) 0.0148 B) 0.0301 C) 0.0451 D) 0.0599

Balance the following equation [? Sil₄→ ? Si + ? I₂] (A) Sil₄ → Si +2 I₂ (B) Sil₄ → 1 Si +1 I₂ (C) Sil₄ → 2 Si +1 I₂ (D) Sil₄ → 1 Si+1 I₂

When sucrose (C₁₂H₂₂O₁₁(s)) is consumed, it reacts with O₂ gas in the body to produce gaseous carbon dioxide and liquid water. Enter the balanced chemical equation for the reaction.

Explain the difference between covalent and non-covalent bonds; Give examples; Characterize electrostatic bonds. Characterize hydrogen bonds. Characterize van der Waals interaction. What is the difference between electrostatic and van der Waals interaction? What is the hydrophobic effect? (describe). What is principle of the maximalization of hydrogen bonds? Explain the mechanism of stabilization of the lipid bilayer. How do membrane lipids interact with each other?

A pure silver ring contains 0.0188 mmol (millimol) Ag. How many silver atoms does it contain? Express your answer in atoms to three significant figures.

Methane burns according to the following equation. CH₄ (g) +2O₂ (g) → CO₂(g) + 2H₂O (g) The combustion of 7.76 L of CH₄ consumes how many liters of O₂, both volumes measured at 25°C and 740 torr? Volume of O₂

What happens to the value of AH for a thermochemical reaction if the reaction is reversed? a. △H has the same numerical value, and the sign changes. b. △H has the same numerical value, and the sign remains the same. C. △H is the reciprocal of the original value, and the sign changes. d. △H is the reciprocal of the original value, and the sign remains the same.

In the 1960s, Bob Dylan (A) composed influential counterculture music, (B) was a student protester at the University of California at Berkeley (C) wrote the book Slaughterhouse-Five. (D) co-founded the Students for a Democratic Society

Balance each of the following chemical equations: a. Ca(OH)₂ + HCl ---> CaCl₂ + H₂O b. Al + Pb(NO₃)₂ ---> Al(NO₃)₃ + Pb C. (NH₄)₂SO₄ + KOH ---> K₂SO₄ + NH₃ + H₂O Write a balanced equation and indicate the reaction type (single or double displacement, decomposition or synthesis) for each of the following: iron (III) bromide + ammonium sulfide → iron(III) sulfide + ammonium bromide aluminum acetate + sodium hydroxide → aluminum hydroxide + sodium acetate

What is the equivalence point? 1. The equivalence point is experimental point when an exact stoichiometric amount of each reactant has been added. 2. The equivalence point is experimental point when pH of the solution is 7. 3. The equivalence point is experimental point when pH of the solution is minimal. 4. The equivalence point is experimental point when the concentration of H+ is equal to the concentration of OH-.

What amount of Al2O3 is produced from the reaction of 3.0 mol Al with 2.0 mol Fe₂O3? 2AI + Fe₂O3 -> Al2O3 + 2Fe A) 1.5 mol B) 2.0 mol C) 3.0 mol D) 6.0 mol

A student has the following data recorded 760. mm Hg, 6.0 L, 197 °C. 712 mm Hg, -76.9 °C. She calculates the initial volume to be -2.5 L. Is her answer correct? Explain why or why not.

Which 2 phases of meiosis are responsible for providing genetic variation in organisms? Make sure to choose 2 answers below. Prophase I Telophase I Cytokinesis Prophase II Metaphase II Anaphase I Anaphase II Telophase II Metaphase I

One of the products of the combustion of propane is carbon dioxide. How many moles carbon dioxide are produced if 6.56 mol gaseous propane are combusted? (Round answers to 2 decimal places - only numerals!)

Will a balloon filled with CH₃F sink or float in air? (A)float (B)sink

Use the following chemical equation to solve each part of this question: Mg+2 HCl → MgCl₂ + H₂ a. If you have 2.5 moles of magnesium as a reactant, how many moles of HCl do you need for the reaction? b. If you have 2.5 moles of magnesium as a reactant, how many moles of MgCl₂ are produced? c. If you have 2.5 moles of magnesium as a reactant, how many moles of H₂ are produced?

A buffer solution is prepared with 0.51 M of nitrous acid, HNO₂, and 0.16 M of sodium nitrite, NaNO₂. For HNO₂, Ka = 4.9 x 10‾⁴. What is the pH of this solution?

Classify each of the following as physical or chemical change: a. a barber cutting your hair: b. water boils: c. eggs, flour, sugar, milk, and yeast are baked into bread: d. a wood log is burned in a fireplace: e. a window is broken: f. milk is poured on cereal: g. an iron nail rusts: