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.
Sir William Alexander Clarke Bustamante.
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Answer:
The experimental feature of the MALDI-MS technique which allows the separation of ions formed after the adduction of tissue molecules:
B) Velocity of ions depends on the ion mass-to-charge ratio.
Explanation:
- The option a is not correct as distance traveled by ions doesn't depend upon the ion charge rather it depends upon time for which you leave the sample to run.
- The option b is correct as velocity of ions depends on the ion mass-to-charge ratio because separation is done due to mass to charge ratio feature.
- The option c is incorrect as time of travel is not inversely proportional to the ion-to-mass ratio because the ion will move across the gel until you stop the electric field.
- The option d is not correct as electric field between MALDI plate and MS analyzer is though uniform but this feature doesn't allow the separation of ions.
Answer:
Requirements for a correctly written chemical equation are reactants and products, their formula and valency
Explanation:
Formula of the given compound are -
1 - Potassium Hydroxide - 
2 - Calcium Nitrate - 
The requirements for a correctly written chemical equation are -
- Identifying reactants and products
- Formula of reactants and products
- Valency of elements
Example of word equation, formula equation, and chemical equation is as follows -
Aluminium + iron9(III)oxide ⇒ aluminium oxide + iron (word equation)
+
⇒
+
(formula equation)
+
⇒
+
(chemical equation)