6. Suppose that a particular chemical substance A is "pure" (contains no "impurities"), and that it...
Astronomers now think that there is a black hole with more than 4 million times the mass of our Sun at the center of our Galaxy? Roughly how large would the event horizon of such a supermassive black hole be? A. the size of our Moon B. about 4 light years across C. about 17 times the size of the Sun D. about the size of an atom (so much mass really compresses the event horizon) E. we can’t answer...
11. Which of the following does the atmosphere of Mercury contain? a) Sulfuric acid b) Methane gas d) Mercury has no atmosphere of any kind c) Oxygen and nitrogen e) none of the above 12. Knowing that it takes about 8 minutes for the sun light to reach the earth, approximately how long does it take for the sun light to reach the planet Saturn? a) 8 minutes b) 40 minutes c) 3 hours and fifty minutes d) five hours...
6. At 60°C, pure substance A has a vapor pressure of 380 mmHg and pure substance B of 140 mmHg. The mole fraction XB=0.15 is in the range of validity of Henry's law. The partial pressure of B at XB=0.1 is 20 mmHg. (a) What is the vapor partial pressure PB at XB=0.15? Answer: PB=30 mmHg. (b) What would PB be at XB=0.15 if the solution were ideal? Answer: PB=21 mmHg. (c) What is the activity coefficient of B, γB,...
Multiple Choice Identify the choice that best completes the statement or a wer the question 1. One of the nearest stars is Alpha Centauri, whose distance is 4.4 light-years. The time it takes light to travel from Alpha Centauri to us is a 1.25 seconds b. 8.3 minutes c. 4.4 years. d. 600 years. 2. Which of the following is false? a The Local Group is a member of the Laniakea Supercluster, which contains thousands of galaxies. b. The Local...
Answer these questions about the substance given by the formula CBr₄: a.) Classify the substance: is it an element, a compound, a homogenous mixture, or a heterogeneous mixture? b.) If the substance is an element, is it a metal, nonmetal, or a metalloid? c.) If the substance is a compound, is it an ionic compound or a molecular compound? d.) What is the name of the substance? e.) What is the mass of a mole of the substance? f.) In...
Astronomers have observed a small, massive object at the center of our Milky Way galaxy. A ring of material orbits this massive object; the ring has a diameter of about 10 light years and an orbital speed of about 210 km/s . A) Determine the mass of the massive object at the center of the Milky Way galaxy. Give your answer in kilograms. B) Give your answer in solar masses (one solar mass is the mass of the sun). C)...
What is true about a pure covalent bond? a. The electrons are shared equally between the atoms in the bond. b. The electrons are transferred from one atom to the other in the bond. c.The electrons are shared unequally between atoms in the covalent bond. d. The electrons are absorbed into the nucleus of one atom in the bond. Which is NOT a property of covalent compounds? a. Poor conductor of electricity in any state b. Often liquid or gas...
Calculations Based on Chemical Formulas (Section 6-5) 6-29 Determine the number of atoms present in 20.0 g! samples of each of the following elements? a. Be b. Ar 6-31 Determine the mass, in grams, of each of the following quantities of substance. a. 6.02 x 102 copper atoms b. 3.01 x 102 copper atoms d. 1 silver atom 6-33 Determine the number of moles of substance present in each of the following quantities. a. 10.0 g He b. 10.0 g...
need help Insert the missing coefficients to completely balance each chemical equation. equation 1: S+6 HNO, H,SO, + NO, +H,0 equation 2: 3 Cu + 8 HNO, Cu(NO), + NO + H2O We were unable to transcribe this imageBalance the equations by inserting coefficients as needed. equation 1: Sb + Cl, — SbCl, equation 2: Mg, N, + HCI — MgCl, +NH, Select the equation that best describes the reaction. O A+B, AB O 4 A +8 B — 4AB,...
8. Consider how the heavy elements that make up planets like the earth are formed. Which of the following is most likely to be true about the origin of Earth? Earth arose around a very ancient star (our sun) that had had plenty of time to synthesize heavy elements. Earth arose in a region of our galaxy where few earlier stars formed so that the hydrogen fuel for our sun was abundant. Earth arose in a region that was very...