You volunteer for chalkboard cleaning duty and you get to work with the erasers. as you rub the dust off of the chalkboard, white chalk dust enters the air and makes you cough. as you clean the chalkboard with the eraser, are you causing a physical change or a chemical change ? explain your answer .

A physical change

Explanation:

A physical state is one that alters the physical properties of matter. In most cases physical changes are easily reversible. The physical properties of matter shows everything about a matter when no change is occuring to it.

When writing on a chalkboard, the state of matter is barely changing from a solid mass of chalk to a powdered form which can easily mark the board.

No change is occuring to the board besides the colour marking it which can easily be erased.

Physical changes can easily be reversed using seperation techniques, in this case, merely wiping the board.

To show that no chemical change has occur, no new kind of compound is formed when marking the board. We can easily collect the powdered chalk back.

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

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