Which is an example of a situation where a zero is not considered to be a
significant digit?

A. When it is to the right of the decimal point, as in 4.20
B. When it is obtained by rounding, as in 3.0
C. When it is between a two non-zero digits, as in 415.505
D. When it comes at the beginning of a number, as in 0.54.

5. how can you decrease the pressure of a gas in a container without changing the volume of the gas?

Darla claims that the first periodic table developed by mendeleev was not completely accurate, so it is not useful at all. harmony argues that it establish the periodic table we use today, making it more credible. who is correct and why? darla is correct, because a model that has any mistakes should be thrown out. darla is correct, because a good model would not need to change. harmony is correct, because mendeleev’s model had all of the information correct in the first version. harmony is correct, because mendeleev’s model made predictions that came true.

For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4al(s)+3o2(g)→2al2o3(s) a) 1 molal, 1 mol o2 b) 4 molal, 2.6 mol o2 c) 16 molal, 13 mol o2 d) 7.4 molal, 6.5 mol o2