An isotope is when an element has the same number of protons and different number of neutrons. That is why the atomic mass changes.
The answer would be: K
Kalium or Potassium is one of the metal that located in the first column of the periodic table. It was a strong base with one valence. If react with water it would have an equation:
2K + 2H2O = 2KOH + H2
The kalium hydroxide will form ion if put on the aqueous state. It will become K+ and OH-, thus increasing the water pH.
Answer: NaCl (s) → NaCl (aq)
Explanation:
Entropy is often associated with the disorder or randomness of a system. Therefore, in each reaction, it is necessary to evaluate if the disorder increases or decreases to understand what happens to the entropy:
1) KCl (aq) + AgNO₃ (aq) → KNO₃ (aq) + AgCl (s) - In this reaction, we have only aqueous reactants in the beginning and in the product we have a precipitate. The solid state is more organised than the liquid, consequently, the entropy decreases.
2) NaCl (s) → NaCl (aq) - In this case, oposite to the first one, we go from a solid state to an aqueous state. The solvation of the ions Na⁺ and Cl⁻ is random while the solid state is very organised. Therefore, in this reaction the entropy increases.
3) 2NaOH (aq) + CO₂ (g) → Na₂CO₃ (aq) + H₂O (l) - In this reaction, the reactants have higher entropy because of the gas CO₂. Therefore, the entropy decreases.
4) C₂H₅OH (g) → C₂H₅OH (l) - In this reaction, the reactant is a gas and the product a liquid. Therefore, the entropy decreases.
"The ability of a base to react with a soluble metal salt" demonstrates characteristic of a base.
<u>Answer:</u> Option D
<u>Explanation:</u>
As the sodium hydroxide react with only with some metals. It is a very strong basic compound with a intense solubility in water and hygroscopic in nature. The ability of base is reflected from its potential to react with metals. In the given reaction:
is an acidic property showing salt which is added with sodium hydroxide and this reaction result into a pale blue precipitate of basic copper hydroxide & sodium sulphate which is neutral salt. The reaction is a double displacement and precipitation reaction.
