How many carbon atoms are there in 45g of carbon?

2.26x 10²⁴ atoms C

Explanation: To get the number of atoms,

First we convert mass of C to moles

45g C x 1mole C / 12 g C

= 3.75 moles C

Cancel g of C

Next convert moles of C to atoms using Avogadro's Number.

3.75 moles C x 6.022x10²³ atoms C / 1 mole C

Cancel out the units of moles C.

= 2.26x 10²⁴ atoms of C

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

a electronegativity decreases beacuse the size of nucleus is bigger.