6 The volume of a gas increased from 2 to 6 L while the temperature was held constant. The
pressure of the gas:
increased by a factor of 3
decreased by a factor of 3
increased by a factor of 4
decreased by a factor of 4

If the volume of a gas increased from 2 to 6 L while the temperature was held constant, the  pressure of the gas decreased by a factor of 3.

Explanation:

Boyle's law that says "The volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure." This means that if the pressure increases, the volume decreases, while if the pressure decreases, the volume increases.

Boyle's law is expressed mathematically as:

Pressure * Volume = constant

or

P * V = k

To obtain the proportionality factor k you must make the quotient:

k= 3

This means that if the volume of a gas increased from 2 to 6 L while the temperature was held constant, the  pressure of the gas decreased by a factor of 3.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3