Aluminium trichloride (
) is an ionic substance that forms crystals in the solid phase. Water molecules may be trapped inside the crystal lattice. We represent this as:
. A learner heated some aluminium trichloride crystals until all the water had evaporated and found that the mass after heating was
. The mass before heating was
. What is the number of moles of water molecules in the aluminium trichloride?
We first need to find n, the number of water molecules that are present in the crystal. To do this we first note that the mass of water lost is
.
The next step is to work out the mass ratio of aluminium trichloride to water and the mole ratio. The mass ratio is:
To work out the mole ratio we divide the mass ratio by the molecular mass of each species:
Next we do the following:
and
So the mole ratio of aluminium trichloride to water is:
And now we know that there are 6 moles of water molecules in the crystal.
Khan academy video on molecular and empirical formulae - 1
Khan academy video on mass composition - 1
Moles and empirical formulae
Calcium chloride is produced as the product of a chemical reaction.
What is the formula of calcium chloride?
What percentage does each of the elements contribute to the mass of a molecule of calcium chloride?
If the sample contains
of calcium chloride, what is the mass of calcium in the sample?
How many moles of calcium chloride are in the sample?
of zinc combines with
of sulphur. What is the empirical formula of zinc sulphide?
What mass of zinc sulphide will be produced?
What percentage does each of the elements in zinc sulphide contribute to its mass?
Determine the formula of zinc sulphide.
A calcium mineral consisted of 29,4% calcium, 23,5% sulphur and 47,1% oxygen by mass. Calculate the empirical formula of the mineral.
A chlorinated hydrocarbon compound was analysed and found to consist of 24,24% carbon, 4,04% hydrogen and 71,72% chlorine. From another experiment the molecular mass was found to be
. Deduce the empirical and molecular formula.
Molar volumes of gases
It is possible to calculate the volume of one mole of gas at STP using what we know about gases.
Write down the ideal gas equation
, therefore
Record the values that you know, making sure that they are in SI units You know that the gas is under STP conditions. These are as follows:
Substitute these values into the original equation.
Calculate the volume of
of gas under these conditions The volume of
of gas at STP is
.
The standard units used for this equation are
in
,
in
and
in
. Remember also that
and
.
A sample of gas occupies a volume of
, has a temperature of
and has a pressure of
. Calculate the number of moles of gas that are present in the sample.
The only value that is not in SI units is volume.
.
In economics, a perfect market refers to a theoretical construct where all participants have perfect information, goods are homogenous, there are no barriers to entry or exit, and prices are determined solely by supply and demand. It's an idealized model used for analysis,
When MP₁ becomes negative, TP start to decline.
Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 •
Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of lab
Kelo
Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 •
Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of labour (APL) and marginal product of labour (MPL)
Quantity demanded refers to the specific amount of a good or service that consumers are willing and able to purchase at a give price and within a specific time period. Demand, on the other hand, is a broader concept that encompasses the entire relationship between price and quantity demanded
Ezea
ok
Shukri
how do you save a country economic situation when it's falling apart
Economic growth as an increase in the production and consumption of goods and services within an economy.but
Economic development as a broader concept that encompasses not only economic growth but also social & human well being.
Shukri
production function means
Jabir
What do you think is more important to focus on when considering inequality ?
sir...I just want to ask one question... Define the term contract curve? if you are free please help me to find this answer 🙏
Asui
it is a curve that we get after connecting the pareto optimal combinations of two consumers after their mutually beneficial trade offs
Awais
thank you so much 👍 sir
Asui
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities, where neither p
Cornelius
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities,
Cornelius
Suppose a consumer consuming two commodities X and Y has
The following utility function u=X0.4 Y0.6. If the price of the X and Y are 2 and 3 respectively and income Constraint is birr 50.
A,Calculate quantities of x and y which maximize utility.
B,Calculate value of Lagrange multiplier.
C,Calculate quantities of X and Y consumed with a given price.
D,alculate optimum level of output .
