What is the percent composition by mass of hydrogen in H20?

2pos suppose an object in free fall is dropped from a building. its starting velocity is 0 m/s. ignoring the effects of air resistance, what is the speed (in m/s) of the object after falling 3 seconds? give your answer as a positive decimal without units. answer here

Astudent made the lewis dot diagram of a compound as shown. mg is written with two dots shown on its top. an o is written on each side of mg. each o has six dots around it. an arrow is shown from one dot on mg toward the vacant space around the o on the right. another arrow is shown from the other dot on mg toward the vacant space around the o on the left. the title of the art is students lewis dot model. what is the error in the lewis dot diagram? an o atom should transfer all its six electrons to mg because the formula is mgo. both electrons of mg should be transferred to one o atom because the formula is mgo. the electrons should be transferred from each o atom to mg because mg has fewer electrons. the number of dots around mg should be four because it has to transfer two electrons to each o.

Why is it important for scientists to review and repeat the work of other scientists? 1.a scientific theory must be tested three times before it is proven. 2.the scientific method only applies to repeated experiments. 3.an experiment may have had errors that the scientists didn't recognize. 4.the results of individual scientists may be influenced by bias. 5.an experiment must be performed twice before the data can be analyzed.