Answer:
5.7 pH
Explanation:
To find pH when given [H+], you use this formula: pH = -log[H+]
-log * 2.1e-6 = 5.6778 = 5.7 pH
<span>The
answer is compound. Elements are
composed of one kind of atoms bonded
together. There are different types of compounds: ionic, complexes, molecular,
and intermetallic compounds. The proportion of
elements in the compound is expressed
using a chemical formula. An example of
an element is Aluminium while an example of a compound is H2S (Hydrogen sulfide).</span>
Answer: single replacement reaction
Explanation:
A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.
A general single displacement reaction can be represented as :

The reaction 
When zinc metal is added to aqueous silver nitrate, zinc being more reactive than silver displaces silver atom from its salt solution and lead to formation of zinc nitrate and silver metal.
Answer: 100x
Explanation:
The actual power or magnification of a compound optical microscope is the product of the powers of the ocular (eyepiece) and the objective lens. The maximum normal magnifications of the ocular and objective are 10× and 100× respectively, giving a final magnification of 1,000×.
Answer:
Arsenic
Explanation:
This is because it has atomic number 33