USAT-E MCQs

Precision describes repeatability.
Measurements can be precise without being accurate.

Accuracy describes agreement with the true or accepted value.
Systematic error can reduce accuracy.

Chemistry examines what matter is made of and how it behaves.
It also studies energy changes accompanying chemical processes.

Matter includes solids, liquids, gases, and plasma.
It is composed of atoms, molecules, or ions.

An element cannot be broken down chemically into simpler substances.
Each element is identified by its atomic number.

Compounds have definite formulas and characteristic properties.
Their components can be separated only by chemical means.

Mixture components retain much of their individual identity.
They can often be separated by physical methods.

Solutions are homogeneous mixtures.
Any sampled portion has approximately the same composition.

Heterogeneous mixtures contain distinguishable regions or phases.
Examples include sand in water and granite.

A physical change alters form or state without changing chemical identity.
Ice and liquid water are both H2O.

The kilogram is the SI base unit of mass.
The gram is one-thousandth of a kilogram.

Rusting forms new iron oxide substances.
Chemical changes involve rearrangement of atoms and new products.