Approximately when did the first plants and arthropods appear on land? A. 444 Ma B. 488 Ma C. 299 Ma D. 416 Ma

Which of the following is NOT a stellar class? A. dwarf B. giant C. supergiant D. megagiant

Examples for reversible change

How can the actual molecular formula be determined? a) from the molar mass divided by the mass of the empirical formula b) from the empirical formula alone c) from the molar mass multiplied by the mass of the empirical formula d) from the molar mass

What are 3 ways that atoms can become more chemically stable

Which of the following cannot be determined from a balanced chemical equation? A. The stoichiometry B. The products C. The reactants D. The reaction mechanism

Which of these are ionic compounds?

Which property can be defined as the ability of a substance to be hammered into thin sheets

Select the group of organelles that is common to both plant cells and animal cells. A. nucleus, cytoplasm, ribosomes, chloroplasts B. cell wall, ribosomes, cell membrane, mitochondria C. cytoplasm, mitochondria, cell wall, nucleus D.

A compound is found to have a composition of 70.4% carbon and 29.6% hydrogen, by mass. what is the empirical formula for the compound?

As you go down a family or group on the periodic table * the atoms become smaller and smaller. the elements become less reactive. the elements become more reactive. the atoms have more and more valence electrons.