Answer:
As the world changes, plants and animals change with it. Aside from a few living fossils, the species we see today are very different from species that lived in the past. Thus, the fossil record can be used to show that organisms changed to meet new conditions. This is the result of evolution of species over time.
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Explanation:
Answer:
1.602 L (or) 1602 mL
Explanation:
Molarity is the amount of solute dissolved per unit volume of solution. It is expressed as,
Molarity = Moles / Volume of Solution ----- (1)
Rearranging above equation for volume,
Volume of solution = Moles / Molarity -------(2)
Data Given;
Molarity = 0.00813 mol.L⁻¹
Mass = 1.55 g
First calculate Moles for given mass as,
Moles = Mass / M.mass
Moles = 1.55 g / 119.002 g.mol⁻¹
Moles = 0.0130 mol
Now, putting value of Moles and Molarity in eq. 2,
Volume of solution = 0.0130 mol / 0.00813 mol.L⁻¹
Volume of solution = 1.60 L
or,
Volume of solution = 1602 mL
Answer:
Model A
Explanation:
Model A represents an atom that is more reactive than the others represented.
Valence electrons actually determine the reactivity of elements. They also determine the properties of elements.
Elements with one valence electron are highly reactive because they need low energy to remove them. They can either gain more electrons to become stable or they share/give out their electrons.
Therefore, Model A is the correct answer because it has one valence electron and its valence electron is farther from the nucleus thereby this makes it more reactive.
Answer:
a)The mass percentages of nitrogen and phosphorus in the compound is 24.34% and 26.95% respectively.
b) 14.78 grams ammonia is incorporated into 100. g of compound.
Explanation:
a) Ammonium dihydrogen phosphate that is 
.
Molecular mass of ammonium dihydrogen phosphate = M
M = 115 g/mol
Percentage of an element in a compound:
Percentage of nitrogen:
Percentage of phosphorus:
b) Percentage of ammonia in 1 molecule of ammonium dihydrogen phosphate.
Molar mass of ammonia = 17 g/mol
Amount of ammonia in 100 grams of compound:
14.78% of 100 g of ammonium dihydrogen phosphate:
14.78 grams ammonia is incorporated into 100. g of compound.
