Seeing signs of a chemical reaction does not always mean that a reaction is happening. For example, a gas (water vapor) is given off when water boils. ... You can tell that it is a physical change because water vapor can condense to form liquid water. In a chemical change, a new substance must be produced.
Answer:
Chemical change :has change in mass, heat is needed, new element is formed, hard to reverse.......
Physicalchange:does not have change in mass, heat is not necessary, no new element is formed, easy to reverse
Answer:
Determining the pH of substances such as purple grape juice and catsup using test strips can be difficult. Why?
Explanation:
Due to the tartaric acid present in these substances, this is a weak acid and is the predominant type of acid in grapes.
pH meters for these substances, measure the total acidity of the sample and convert it into tartaric acid concentration; The test strips are a qualitative method of measurement and their result can give different opinions.
A - 1 CH4+ 1 O2 = 1 CO2+2 H2
b - 2 Al+3 Cl2 = 2 AlCl3
c - 1 CH2O+ 1 H2 = 1 CH3OH
*The ones that have the coefficient of 1 you can leave blank but if you have to put a number just put 1
