Volatile organic compounds are compounds that easily evaporate at standard room temperature and pressure. They are considered harmful to the environment if regulations are not followed. Examples of this are:
Benzene
Ethanol
Benzopyrene
Ethenone
Acetic acid
Methane
Butane
Heptane
Pentane
Answer:
Explanation: Over pumping refers to pumping fresh water and reducing the level of an underground layer of water. In coastal areas, the lower underground layer of water is infiltrated with salt water, eventually increasing the salinity of the underground layer of water to the point that it is not drinkable. The scarcity of water in the coastal areas because the water in the coastal areas is not drinkable.
Answer : The volume of concentrated hydrochloric acid is, 0.25 liters
Explanation :
Using neutralization law,
where,
= molarity of concentrated hydrochloric acid = 12 M = 12 mole/L
= molarity of hydrochloric acid = 6 M = 6 mole/L
= volume of concentrated hydrochloric acid = ?
= volume of hydrochloric acid = 500 ml = 0.5 L
Now put all the given values in the above formula, we get the volume of concentrated hydrochloric acid.
Therefore, the volume of concentrated hydrochloric acid is, 0.25 liters
(1) Kr (3) N2O4
(2) LiOH (4) NaI
Answer: Option (3) is the correct answer.
Explanation:
A molecular compound is a compound in which atoms used to share electrons and thus results in the formation of covalent bonds.
For example, is a covalent compound and hence, it is a molecular compound.
Whereas LiOH and NaI are ionic compounds as their atoms has transferred electrons.
Therefore, we can conclude that out of the given options, is the formula which represents a molecular compound.
Answer:
-909.3KJ/mole
Explanation:
The heat of reaction is accessible from the heat of formation of reactants and products using the formula below:
ΔH = Σ ΔHf products - Σ ΔHf reactants
Before we proceed, it is important to know that the enthalpy of formation of element is zero ,be it a single element or a molecule of an element.
From the reaction for the formation of sulphuric acid, we know we need to know the heat of formation of sulphur (vi) oxide and water. The examiner is quite generous and have us for water already.
Now we need to calculate for sulphur (vi) oxide. This is calculated as follows:
We first calculate for sulphur(iv)oxide. This can be obtained from the reaction between sulphur and oxygen. The calculation goes thus:
ΔH = Σ ΔHf products - Σ ΔHf reactants
ΔH = [ 1 mole suphur(iv) oxide × x] - [ (1 mole of elemental sulphur × 0) + (1 mole of elemental oxygen × 0]
We were already told this is equal to -296.8KJ. Hence the heat of formation of sulphur(iv) oxide is -296.8KJ.
We then proceed to the second stage.
Now, here we have 1 mole sulphur (iv) oxide reacting with 0.5 mole oxygen molecule.
We go again :
ΔH = Σ ΔHf products - Σ ΔHf reactants
ΔH = [ 1 mole of sulphur (vi) oxide × y] - [ (1 mole of sulphur (iv) oxide × -296.8) + (0.5 mole of oxygen × 0)].
We already know that the ΔH here equals -98.9KJ.
Hence, -98.9 = y + 296.8
y = -296.8KJ - 98.9KJ = -395.7KJ
We now proceed to the final part of the calculation which ironically comes first in the series of sentences.
Now, we want to calculate the standard heat of formation for sulphuric acid. From the reaction, we can see that one mole of sulphur (vi) oxide, reacted with one mole of water to yield one mole of sulphuric acid.
Mathematically, we go again :
ΔH = Σ ΔHf products - Σ ΔHf reactants
ΔH = [ 1 mole of sulphuric acid × z] - [( 1 mole of sulphur vi oxide × -395.7) + ( 1 mole of water × -285.8)].
Now, we know that the ΔH for this particular reaction is -227.8KJ
We then proceed to to open the bracket.
-227.8 = z - (-395.7 - 285.8)
-227.8 = z - ( -681.5)
-227.8 = z + 681.5
z = -227.8-681.5 = -909.3KJ
Hence, ΔH∘f for sulphuric acid is -909.3KJ/mol
Mass of oxygen : 54 g
Conservation of mass applies to a closed system, where the masses before and after the reaction are the same
Reaction
mass before reaction = mass after reaction
mass C + mass O₂= mass CO₂
A
Which model is composed of rapidly moving particles?
B.
Which model is composed of particles vibrating in place?
C
Which model is composed of electrically charged particles?
Which model is composed of particles sliding past each other?
Answer:
C Which model is composed of electrically charged particles?
Explanation:
The best question to resolve and determine the model which is plasma is to find one that is composed of electrically charged particles.
Plasma is one of the states of matter which is characterized by ions and other charged particles.
Matter is anything that has weight and occupies space.
There are four known states of matter which are:
Plasma is the only state of matter made up of charged particles.