I have measuring tools in ml. It turns out 100ml = 100g so fourth
"No, They are two different things.
1 ml (millilitre) is a "volume", it measures how much three-dimensional space an object occupies.
1g (gram) is a "mass", it measures how much material an object contains.
Somethings are more "dense", meaning that the same amount of material occupies a smaller space - think of the metal Pb. Somethings are less dense - the same amount of material occupies a huge space - hydrogen gas in room temperature and atmospheric pressure, for example.
It happens that 1ml volume of pure water at 4.0° Celsius (39.2° Fahrenheit) contains very close to 1g of material (0.9998395g). This is why people sometimes confuse the two quantities." -answer from Quora
TL,DR: Volume and Mass can NOT be measured this way! DO NOT FILL A CUP TO 25 MILLILITERS OF SN AND BELIEVE IT IS EXACTLY 25 GRAMS