Ihave absolutely no idea how to do this and chemistry is my worst subject

1 - 2 NaBr + Ca(OH)2 -> CaBr2 + 2NaOH [Double Replacement]. To balance this equation, look at the subscripts for each element. You can see that Hydroxide and Bromine both are not balanced, so you need to balance them. In order to do this, set up a table with reactants on one side and the products on the other. See the image posted.

2 - 2NH3 + H2SO4 -> (NH4)2SO4 [Synthesis]. Both reactants merge to form one product, thus being synthesis. There needs to be a coefficient of 2 in front of NH3 in order to balance the equation.

3 - 4C5H9O + 27O2 -> 20CO2 + 18 H2O [Combustion]. This is because the reactants produce Carbon Dioxide and water.

4 - 3Pb + 2H3PO4 -> 3H2 + Pb3(PO4)2 [Single Replacement]. This is because Hydrogen was replaced by Lead.

5 - Li3N + 3NH4No3 -> 3LiNo3 + (NH4)3N [Double Replacement].

Hope this helps!

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation: