Answer:
balanced;
unbalanced;
unbalanced;
balanced;
Explanation:
CaO + 3C → CaC2 + CO //all elements are balanced
Na + H2O → 2NaOH + H2 //Na is not balanced on the left
4Fe + O2 → 2Fe2O3 //O is not balanced on the left
2Mg + O2 → 2MgO //left is equal to right, balanced
(NH4),CO
(NH₄)₂ CO₃
Explanation:
The chemical formula for ammonium carbonate is (NH4),CO
Ammonium carbonate is made up of:
Ammonium ion
Carbonate ion
Ammonium ion is represented by NH₄⁺
Carbonate ion is represented by CO₃²⁻
Now to write the formula, we are going to use their combining powers;
NH₄⁺ CO₃²⁻
Combining
power 1 2
Exchange
of power 2 1
Formula of compound (NH₄)₂ CO₃
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Answer:
9000 BC
Explanation:
Although various copper tools and decorative items dating back as early as 9000 BCE have been discovered, archaeological evidence suggests that it was the early Mesopotamians who, around 5000 to 6000 years ago, were the first to fully harness the ability to extract and work with copper.
Answer:
The chemical compound Mg(NO3)2, also known as magnesium nitrate, is very soluble, especially in water.