A sample of nitrogen gas reacts with an excess of hydrogen gas to give an actual yield of 23.5 g NH3. The theoretical yield is 26 g. What is the percent yield for this reaction?
Reaction: N2(g) + 3 H2(g)
→ 2 NH3(g)

The earth's moon is unusually large. two popular theories of the moon's origin include the "sister world" hypothesis, which states that the moon formed from the same materials as the earth, near enough to the earth that they fell into orbit around each other. a second theory is the "capture" hypothesis, in which the moon formed elsewhere in the solar system, and the earth's gravity pulled it into its orbit. studies of what the moon is made of indicate that some of its materials had to come from the earth or from the same area of the solar system where the earth had formed. at the same time, the moon does not contain much of the material that makes up the earth's core, so the moon could not have formed from the same materials as the earth. how do the two facts above affect the described theories of the moon's origin? a. they show that scientists will never agree on where the moon came from. b. they show that more experiments on moon formation need to be done. c. they show that no theory accounts for the existence of the moon. d. they show that neither theory is complete and entirely correct.

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the independent variable in galileo's experiment? a. the speed of the ball b. the slope of the plane c. whether the ball moved d. what the ball was made of

28. which is not a reason that water is used to store spent fuel rods from nuclear power plants? water increases the speed of the chain reaction in the fuel rods. water protects nuclear power plant workers from the high temperature and radiation of the fuel rods. water acts as a radiation shield to reduce the radiation levels. water cools the spent rods. salts action