Acovalent bond between two atoms occurs when the atoms a. lose or gain electrons and become ions. b. share pairs of electrons. c. transfer valence electrons completely from one atom to another. d. have an electrical attraction between them.

Several kinds of bears are found on earth. most bears are brown or black, but one type of bear, the polar bear, is white. what process led to this difference in fur color? explain your answer.

The reactions shown here can be combined to make the overall reaction c(s) + h2o(g) ⇌ co(g) + h2(g) by reversing some and/or dividing all the coefficients by a number. a. c(s) + o2(g) → co2(g) k=1.363×10^69 b. 2 h2(g) + o2(g) → 2 h2o(g) k=1.389×10^80 c. 2co(g) + o2 (g) → 2 co2(g) k=1.477×10^90

The vapor pressure of ethanol is 1.00 × 102 mmhg at 34.90°c. what is its vapor pressure at 61.61°c? (δhvap for ethanol is 39.3 kj/mol.)