You mix solution a with solution b in a beaker. which of the following observations does not you prove that a chemical reaction has occurred?
a the beaker becomes warm.
b you see gas bubble out of solution.
c solution a, solution b, and the mixture are all yellow.
d none of the above; all prove that a chemical reaction has occurred.
in the reaction described by the word equation sodium + water sodium hydroxide + hydrogen gas
a sodium hydroxide is a product.
b sodium is a product.
c both (a) and (c)
d water is a reactant.

Part 1: A and B; Part 2: A and D

Explanation:

Part 1. Evidence of reaction

The evolution of heat and/or bubbles of gas are evidence that a reaction has occurred.

C is wrong. If adding yellow Solution A to yellow Solution B gives a yellow mixture, that is not evidence of reaction. You need a colour change to provide evidence.

Part 2. Identifying reactants and products

Reactants are on the left side of the reaction arrow, and products are on the right.

Thus, water is a reactant, and sodium hydroxide is a product.

B is wrong. Sodium is a reactant.

1) Solution A, solution B, and the mixture are all yellow.

2) sodium hydroxide is a product

water is a reactant.

Explanation:

In a chemical reaction mixture , change in colour, change in temperature of reaction mixture or evolution of gas all confirm that a chemical reaction has taken place. If the colour of the reaction mixture remains the same overtime, it may be an indication that a chemical reaction did not take place in the mixture.

Looking at the reaction equation:

sodium + water> sodium hydroxide + hydrogen gas

Species on the lefthand side of any chemical reaction equation are called reactants while the species on the right hand side of the reaction equation are called products . hence sodium hydroxide is a product while water is a reactant.

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