how many mole are there in 30 g of water if 50 mg of it is evaporated and 6g is cooled to 4 Kelvin ?
bayanker prashan XD
Answers
Water (H2O) is made from 2 atoms of hydrogen and 1 atom of oxygen. A mole of water molecules would be 2 moles of hydrogen atoms plus 1 mole of oxygen atoms. From the periodic table we see the atomic weight of hydrogen is 1.0079 and the atomic weight of oxygen is 15.9994.
Answer:
The only time you'll see a number to the left of the formula for a chemical compound is when the compound is involved in a reaction, and you're looking at the equation for the reaction. When you see a number in this context, it's called a coefficient, and it's there to balance the equation. A balanced reaction equation is one that shows the same number of elements on both the reactant side and the product side, which is required by the law of conservation of mass. The little number you see to the right of the symbol for an element is called a subscript. That number indicates the number of atoms of that element present in the compound. When balancing an equation, you can change the coefficients but not the subscripts.