HEM1 Study guides, Class notes & Summaries

Mass Number - ANSWER-total number of neutrons and protons in an atom; # protons + # electrons p - ANSWER-Most nonmetallic elements are found in which block of the periodic table? Positive matter is concentrated in the central core - ANSWER-Ernest Rutherford disproved J.J. Thomson's plum-pudding model of the atom by showing that... Potassium - ANSWER-Plants use up copious amounts of which alkali metal, preventing most of it from being washed out to sea? 2:1:1:2 - ANSWER-What is the r...

1. Question: When comparing Be2 and H2: 2. Question: Atoms that are sp2 hybridized form ____ pi bond(s). 3. Question: The hybridization of the nitrogen atom in the cation NH2+ is: 4. Question: Which one of the following molecules has an atom with an incomplete octet? 5. Question: Nitrous oxide (N2O) is sometimes called "laughing gas". What is the formal charge on the central nitrogen atom in the most favorable Lewis structure for nitrous oxide based on minimizing formal charge overall? 6....

1. Question: A sample of oxygen gas has a volume of 3.52 L at 27°C and 800.0 torr. How many oxygen molecules does it contain? 2. Question: Consider a sample of gas in a container on a comfortable spring day. The Celsius temperature suddenly doubles, and you transfer the gas to a container with twice the volume of the first container. If the original pressure was 12 atm, what is a good estimate for the new pressure? 3. Question: Gas A and gas B are combined in a flask at initial pressures of 1...

1. Question: If 0.274 moles of a substance weighs 62.5 g, what is the molar mass of the substance, in units of 2. Question: What volume of 18 M sulfuric acid must be used to prepare 1.80 L of 0.215 M H2SO4? 3. Question: What is the molecular mass of Br2? 4. Question: What is the molar concentration of sulfate ions in a 0.150 M Na2SO4 solution? 5. Question: How many moles of hydrogen chloride are contained in a 52.6 g sample of this gas? 6. Question: 1.00 mole of O2 contains the same number ...

1. Question: A sample of oxygen gas has a volume of 3.52 L at 27°C and 800.0 torr. How many oxygen molecules does it contain? 2. Question: Consider a sample of gas in a container on a comfortable spring day. The Celsius temperature suddenly doubles, and you transfer the gas to a container with twice the volume of the first container. If the original pressure was 12 atm, what is a good estimate for the new pressure? 3. Question: Gas A and gas B are combined in a flask at initial pressures of 1...

Which species will have the greatest absolute entropy at 25°C? Select one: A. C4H10(g) B. H2O(l) C. C2H5OH(l) D. C2H2(g) E. Ne(g) Which is a statement of the second law of thermodynamics? Select one: A. The energy of the universe is constant. B. The energy of the universe is decreasing. C. The entropy of the universe is increasing. D. The enthalpy of the universe is constant. E. The entropy of the universe is constant. My Account Question 3 Correct 5.00 points out of 5.00 Que...

1. Question: Dry ice (carbon dioxide) changes from a solid to a gas at –78.5°C. What is this temperature in °F? 2. Question: The state of matter for an object that has both definite volume and definite shape is 3. Question: In 1828, the diameter of the U.S. dime was changed to approximately 18 mm. What is this diameter when expressed in nanometers? 4. Question: A piece of antimony with a mass of 17.41 g is submerged in 46.3 cm3 of water in a graduated cylinder. The water level increases t...

1. Question: When comparing Be2 and H2: 2. Question: Atoms that are sp2 hybridized form ____ pi bond(s). 3. Question: The hybridization of the nitrogen atom in the cation NH2+ is: 4. Question: Which one of the following molecules has an atom with an incomplete octet? 5. Question: Nitrous oxide (N2O) is sometimes called "laughing gas". What is the formal charge on the central nitrogen atom in the most favorable Lewis structure for nitrous oxide based on minimizing formal charge overall? 6....

1. Question: What is the volume, in cubic centimeters, of a brick that is 4.0 in × 2.7 in × 8.0 in? 2. Question: A sailor circumnavigated the earth and covered 4,264,000 meters. Express this number in standard scientific notation. 3. Question: The state of matter for an object that has both definite volume and definite shape is 4. Question: How many of the following numbers contain 3 significant figures? 5. Question: In the spring of 2008, gasoline cost £1.029 per Liter in London. On the ...

Potassium chlorate (used in fireworks, flares, and safety matches) forms oxygen and potassium chloride when heated. KClO3(s) → KCl(s) + O2(g) [unbalanced] What mass of oxygen gas is formed if 26.4 g of potassium chlorate decomposes completely? Select one: A. 6.86 g B. 99.1 g C. 4.60 g D. 10.3 g E. 223 g My Account Question 2 Correct 5.00 points out of 5.00 Question 3 Correct 5.00 points out of 5.00 Ammonia reacts with diatomic oxygen to form nitric oxide and water vapor as ...