Magnesium + Hydrocloric acid -> Magnesium chloride + hydrogen
You can observe a single displacement reaction
"Describe to show that the has formed is hydrogen"
I don't know what you mean. I can show the chemical equation though.
Mg(s) + 2 HCl(aq) --> MgCl 2(aq) + H 2(g)
A hydrogen atom has 0 charge because its two constituents are oppositely charged; and understand p + q as the number located a distance |q| from p, in the positive or negative direction depending on whether q is positive or negative.
The two ways to measure the sand in a sand castle are by counting the number of pails of sand used to build the castle and by determining the mass of the sand used in building the castle. The first method makes use of the volume of the pail to determine the amount of sand while the second method is a more quantitative way.<span />