Caffeine’s molecular formula is C8H10N4O2. the molar mass of caffeine is 194 g/mol. what is the percentage of oxygen in caffeine? a) 8.2%
b) 16.5%
c) 28.9%
d) 49.5%

To save time, you can approximate the initial mass of the solid to the nearest ±1 g. for example, if you are asked to add 14.3 g of copper, add between 13 g and 15 g. which of the following sets include two samples with an equal density? which all that apply below 15.4 g gold and 18.7 g silver 15.2 g copper and 50.0 g copper 20.2 g silver and 20.2 g copper 11.2 g gold and 14.9 g gold

Which traits do human embryos have that link them to a common ancestor with fish and reptiles? a. scales and tail b. gill slits and scales c. tail and gill slits d. hair and tail

Which explanation is true about what happens to a ray of light when it strikes a mirror? a. a light ray is transmitted toward a mirror at a certain angle. the light ray is then reflected by the mirror at an equal angle but in the opposite direction of the transmitted ray. b. an incident ray strikes a mirror at an angle with a line perpendicular to the mirror. the light ray is then reflected at an angle equal to the angle of incidence but on the opposite side of the perpendicular line. c. a reflecting ray strikes a mirror at an angle with a line perpendicular to the mirror. the light ray is then refracted at an angle equal to the angle of the reflecting ray and on the same side of the perpendicular line. d. an incident ray strikes a mirror at an angle with a line parallel to the mirror. the light ray is then transmitted at an angle equal to the angle of incidence but on the opposite side of the parallel line. you so much! : -d take the time to try and answer correctly.