Which contain coordinate covalent bonds?

a) bacl2
b)ca(n03)2
c) bcl4-
d)tibr4

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy

Why must humans find substitutes for many minerals found on earth? (a) form at an extremely slow rate (b) controlled by other countries (c) too deep in the earth to collect

When can a hypothesis be elevated to the status of a theory? a) when it is validated by an experiment b) when data gathered from an experiment precisely fits predictions c) when it can be proved to be true d) when it meets the test of repeated experimentation