Achemist samples a river's water to measure the amount of fertilizer runoff from the area farms. in a 0.0335 l sample, the chemist measures 258 μg of nitrate. express the concentration of nitrate in parts per million (ppm) and parts per billion (ppb). assume the density of the river water sample is 1.00 g/ml.

Imagine that a new planet is discovered with two moons of equal mass: moon a and moon b. the mass of the new planet is greater than the combined mass of its moons. moon a is farther away from the new planet than moon b. what is the planet's gravitational pull on moon a compared to the planet's gravitational pull on moon b? the planet's gravity repels moon a with a greater force than it repels moon b, which is why moon a is farther away. the gravitational pull on moon b is greater than on moon a because moon b is closer to the new planet than moon a. the gravitational pull on moon b is greater than on moon a because moon b is farther away from the new planet than moon a. the gravitational pull on moon a is the same as the gravitational pull on moon b because distance does not affect the planet's gravity.