Answer:
The concentration of this solution in units of pounds per gallon is 
Explanation:
Units of measurement are established models for measuring different quantities. The conversion of units is the transformation of a quantity, expressed in a certain unit of measure, into an equivalent one, which may or may not be of the same system of units.
In this case, the conversion of units is carried out knowing that 1 μg are equal to 2.205*10⁻⁹ Lb and 1 mL equals 0.00022 Gallons. So
If 1 μg equals 2.205*10⁻⁹ lb, 2.77 μg how many lb equals?
lb=6.10785*10⁻⁹
So, 2.77 μg= 6.10785*10⁻⁹ lb
Then:
You get:
<u><em>The concentration of this solution in units of pounds per gallon is </em></u><u><em></em></u>
Answer : The correct options are, 
and 
Explanation :
Single displacement reaction : It is a type of chemical reaction in which the more reactive element displaces the less reactive element.
Option A reaction : 
It is an example of double displacement reaction because in this reaction a positive cation and a negative anion of the two reactants exchange their places to form two new products.
Option B reaction :
It is an example of single displacement reaction.
Option C reaction : 
It is an example of combination reaction because in this reaction two reactants react to give a single product.
Option D reaction : 
It is an example of decomposition reaction because in this reaction a single reactant decomposes into two or more products.
Option E reaction :
It is an example of single displacement reaction because in this reaction the most react element, aluminium displaces the less reactive element, hydrogen.
Hence, the options B and E are single displacement reactions.
Answer:
Inhalation (via the respiratory tract)Absorption (via mucous membranes such as the eyes) Ingestion (via the gastrointestinal tract)
Explanation:
The opening where an infectious disease enters the host's body such as mucus membranes, open wounds, or tubes inserted in body cavities like urinary catheters or feeding tubes.
Answer:
The atomic number of<span>N<span>157</span></span>
The number of protons is 7
The number of electrons is 7
The number of neutrons is 8
Explanation:
The atomic number of Nitrogen is 7 because Nitrogen has 7 protons.
The seven protons attract 7 electrons in the ground state.
If the atom had fewer or more than 7 protons the atom would not be Nitrogen.
The mass of the atom is the sum of protons and neutron. so
p + n = mass ( protons (p) and neutrons(n) both have an atomic mass of one
7 + n = 15 subtract 7 from both sides
<span>7−7+n=15−7</span>
n = 8
Phosphorus tribromide is a covalent compound because they share electron pairs.
