Answer:
Um, where is the article?
Combining oxygen gas and hydrogen gas to form liquid water is a chemical change. Pretty sure the rest are physical changes because a chemical change happens when a substance is altered completely. A physical change is when a substance keeps its components (I dunno what word to use) but just changes into a diferent shape. At least thats how my teacher explained it to me.
Answer:

Explanation:
Hello,
In this case, for the reaction between hydrochloric acid and sodium hydroxide, for 2.4 g of base, we can compute the neutralized grams of acid by applying the 1:1 molar ratio between them and their molar masses, 36.45 g/mol and 40 g/mol respectively as shown below by stoichiometry:

Best regards.
Answer:
magnet field must also be around the same coil to produce current