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:
Q1) solids are strong, gasses are weak
Explanation:
- Solids are Tightly packed molecule with no gap or space in between.
- Gasses are loosely packed and move freely in our atmosphere.
- Examples of solids are Wood, steel, plastic etc
- Example of gasses are oxygen, Carbon dioxide, nitrogen
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Answer:
A. It is the ratio of the concentrations of products to the concentrations of reactants.
Explanation:
The equilibrium constant of a chemical reaction is the ratio of the concentration of products to the concentration of reactants.
This equilibrium constant can be expressed in many different formats.
- For any system, the molar concentration of all the species on the right side are related to the molar concentrations of those on the left side by the equilibrium constant.
- The equilibrium constant is a constant at a given temperature and it is temperature dependent.
- The derivation of the equilibrium constant is based on the law of mass action.
- It states that "the rate of a chemical reaction is proportional to the product of the concentration of the reacting substances. "
E.g. in H3PO4 (O, -2).
8. The sum of the oxidation states of all the atoms in a species must be equal to net charge on the species. e.g. Net Charge of HClO4 = 0, i.e. [+1(H)+7(Cl)-2<span>*4(O)] = 0.</span>
