which one of the following is a physical change?
a. in cold weather, water condenses on the inside surface of single pane windows.
b. grape juice left in an open unrefrigerated container turns sour.
c. when ignited with a match in open air, paper burns
d. when heated strongly, sugar turns dark brown.
e. when treated with bleach, some dyed fabrics change color.

What’s the scientific notation for the number 6,840,000,000

Which statement best describes the relationship between period and frequency of light waves? a) in wave b the period increases and the frequency decreases from wave a. b) in wave a the period increases and the frequency decreases from wave b. c) in wave b the period is shorter and the frequency is greater than in wave a. d) in wave a the period is shorter and the frequency is greater than in wave b.

Which is an example of the practical pursuit of alchemy? a. forming perfect substances. b. transforming base metals. c. developing metalworking techniques. d. linking spiritual characteristics with material substances.