Burning of the candle is both physical and chemical change.burning of the candle causes the candle to melt the wax.so the wax has changed it was solid now it is liquid.the wax combines with the atmospheric oxygen and changes to carbon dioxide,heat and light.thus both the changes are accompanied by the burning of the candle.
Ice is the solid phase of water, so it is not silicate.
HF + NaOH = NaF + H2O
Aqueous sodium fluoride (NaF) and water are the products of the reaction between hydrofluoric acid (HF), a weak acid and sodium hydroxide (NaOH), a strong base.
It is a straightforward acid-base reaction, despite the fact that hydrogen fluoride is a weak acid that doesn't completely dissociate in water (the equilibrium between the dissociated & undissociated acid will however be pushed to the right as the reaction progresses and all of the acid will eventually be neutralized). Water and sodium fluoride are the products
What exactly is an acid-base reaction?
An acid-base reaction is a chemical reaction that occurs between the reactants, which are an acid and a base. This reaction produces salt and water as byproducts. An acid-base reaction is a double replacement reaction in which ions swap positions.
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M of water = 2(1) + 16 = 18 g/mol
n of water = 24g/(18g/mol) = 4/3 mol
n of H2O : n of O2 = 2 : 1
2:1 = 4/3 : x
x = (4/3)/2 = 2/3 mol of O2