Answer:
If it is pure, the substance is either an element or a compound. If a substance can be separated into its elements, it is a compound. If a substance is not chemically pure, it is either a heterogeneous mixture or a homogeneous mixture. If its composition is uniform throughout, it is a homogeneous mixture.
A and D
Density is mass over volume, if mass decreases or volume increases density decreases
<span>In physics WAVELENGTH IS THE DISTANCE BETWEEN REPEATING UNITS OF A PROPAGATING WAVE of a given frequency. It is commonly designated by the Greek letter lambda (λ). Examples of wave-like phenomena are light, water waves, and sound waves. The wavelength is related to the frequency by the formula: wavelength = wave speed / frequency. Wavelength is therefore inversely proportional to frequency. Higher frequencies have shorter wavelengths. Lower frequencies have longer wavelengths, assuming the speed of the wave is the same.</span>
Gaseous
The atoms are taking up the volume of the entire container
