physics and chem questions under the read more
22. A car travelling at 90 km/h decelerates at a constant 1.6 m/s2. Calculate (A) the distance the car goes before it stops, (b) the time it takes to stop, and (c) the distance it travels during the first and third seconds.
27. A person driving her car at 50 km/h approaches an intersection just as the traffic light turns yellow. She knows that the yellow light lasts only 2.0 seconds before turning red, and she is 30 m away from the near side of the intersection. Should she try to stop, or should she make a run for it? The intersection is 12m wi, and her car's maximum deceleration is -6.0 m/s2. Also her car takes 7.0s to accelerate from 50 km/h to 70 km/h. Ignore the length of her car and her reaction time.
31. (a) How long does it take a brick to reach the ground if dropped from the height of 50.0 m? (b) What will be it's velocity before it reaches the ground?
32. A baseball is thrown vertically into the air with a speed of 24.0 m/s (a) How high does it go? (b) How long does it take to reach the ground?
CHEMISTRY
p.309, 8.48 - Consider the nitryl cation, NO2+
(a) Write one or more appropriate Lewis structures for this species
(b) Are resonance structures needed to describe the structure?
(c) With what familiar species is it isoelectronic?
8.50 - Based on Lewis Structures, predict the order of N---O (N to O bonds) bond lengths in NO+, NO2- and NO3-
p. 310, 8.58 - Draw the Lewis structures for each of the ff. molecules or ions. Identify those that do not obey the octet rule, and explain why they do not.
(a) NO
(b) ICl2- [that's capital "i" and "Cl" is chlorine, just so no one gets confused],
(c) SO2,
(d) BCl3,
(e) XeF4
8.60 (a) Describe the molecule Chlorine Dioxide, ClO2, using three possible resonance structures
(b) Do any of these resonance structures satisfy the octet rule for every atom in the molecule? Why or why not?
(c) Using formal charges, select the resonance structure(s) that is/are most important
p. 311, 8.80 - (a) Determine the formal charge on the chlorine atom in the hypochlorite ion, ClO- (Capital C, regular L, capital O), and the perchlorate ion ClO4- (Capital C, regular L, capital O), if the Cl atom has an octet.
(b) What are the oxidation numbers of chlorine in ClO- and ClO4-?
(c) What are the essential differences in the definitions of formal charge and oxidation number that leads to the differences to parts (a) and (b)?
8.82 - Although I3- is known, F3- is not. Using Lewis structures, explain why F3-