E since its a physical model i.e. you can touch and feel the model :)
A.meter is the is the answer to the problem you and and if you need to know why then type back
Answer:
Atom
Explanation:
atom: The basic unit of matter; the smallest unit of an element, having all the characteristics of that element; consists of negatively-charged electrons and a positively-charged center called a nucleus.
Answer:
molarity = no. of moles of solute / 1 liter .
* one moles of sodium hydroxide = 40 gm of sodium hydroxide.
so we can said ; if want prepare 1 molar NaOH solution then we need 40 gm NaOH dissolve in one liter of water so it became one 1 molar NaOH solution
Explanation: