AVCN

Specialized proteins called enzymes accelerate chemical reactions in living systems by ………………. the activation energy.

• increasing

• lowering

• raising

• generating

The Latin prefix "sesqui-" means: *

• one

• one half

• double

• one and a half

An ……………….. substance is a substance which consists of atoms of only one kind.

• elementary

• compound

• molecule

• impure

The products of reversible reactions can readily revert back to form the …………… reactants.

• new

• joined

• original

• combined

The bond between Na+ and Cl in the salt molecule is called …………... bond.

• covalent

• ionic

• disulfide

• hydrogen

In a synthesis reaction, atoms, ions, or molecules are ………. to form a large molecule.

• broken down

• combined

• release

• generated

Chemical elements are designated by letter abbreviations called chemical ………... .

• symbols

• atoms

• signs

• molecules

A gas does not possess either ……………. shape or size.

• round

• free

• definite

• visible

A liquid has a definite …………., but does not have a definite …………. *

• shape/volume

• volume/shape

• volume/size

• size/volume

The chemical properties of an atom are largely due to the number of electrons in its outermost ………... .

• electron

• shell

• nucleus

• nuclei