How many Signifact figures does 0.000300

3 significant digits

Explanation:

The first 0 don't count (that's the rule in significant digits). So 3,0,0 are left over. Count them and total will be 3 significant digits. (remember the last zero count if there is a decimal but the first zeros doesn't count even with the decimals)

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance

b.

the accuracy of the data.