Answer is: <span>chemical change occurred.
Electrolysis reaction: 2H</span>₂O → O₂ + 2H₂.
In thic electrolysis reaction two gases are formed, one is oxygen with boiling point of -183°C and second one is hydrogen with boiling point of -253°C. This is chemical change because from one molecule two molecules are produced and because they have new boiling points, boiling point of water is 100°C.
The melting point (or, rarely, liquefaction point) of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard pressure.
Answer:
Equation 2, because Fe is being more reactive, replaces Cu from CuSO₄.
Explanation:
- Equation 1 is: <em>CuSO₄ + 2NaOH → Na₂SO₄ + Cu(OH)₂.</em>
The reaction between CuSO₄ and NaOH will give Na₂SO₄ and Cu(OH)₂ which is a precipitate "replacement reaction".
- While, equation 2 is: <em>CuSO₄ + Fe → Cu + FeSO₄.</em>
The reaction between CuSO₄ and Fe will produce Cu and FeSO₄.
Thus, it is used to extract Cu because Fe is more reactive than Cu, so it can replace it in its salts and Cu can be extracted.
- <em>So, the right choice is: Equation 2, because Fe is being more reactive, replaces Cu from CuSO₄.</em>
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Answer:
Here's what I get
Explanation:
The etching gel used in many dental procedures contains
- 10 % to 50 % phosphoric acid in water
- a thickening agent consisting of hydrocarbon polymers and a colloidal silica sol
- a colouring agent such as cobalt aluminate blue spinel (CoAl₂O₄) to make it visible on a tooth.
Answer: In the Nitrogen family
Explanation:
Other elements in the family are: phosphorus, arsenic, antimony, and bismuth.