English To Calculate
Stoichiometry
Stoichiometry is the basic chemical calculation that states quantitative relation of chemical formulas and chemical equations.
Here are the materials you need to know to understand, from the concept
of moles and molar masses, empirical formulas and molecular formulas,
basic stoichiometry of solutions and ideal gases, and the writing and
equalization of reactions, with examples of problems and discussions.
The molar mass,}, is defined as the mass of 1 mol entity (atom, ion, molecule, unit of formula) of matter. The unit of the molar mass (}) is a gram / mol.
Stoichiometric Material: Mass relation, number of moles, and number of atoms of elements
(Source: Chang, Raymond, 2010. Chemistry (10th edition) New York: McGraw Hill)
Avogadro's law states that at certain pressures and temperatures and
fixed, the volume of the gas is directly proportional to the amount of
gas.
![V \infty n [P, T \: konstan]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_sjY5Jl3dQ1mIRX6qwheQCMkFgwAhpKyhm42uQIQn6n-yRHpaIK0twBzEjKZfuQfNtC-KFDLSXUoNr8A4Wsuj3svocaCqZhV63epEm5ENwu56t52cBBg9NwHjcGPUuwGI4llnuXwGkW8zF-A1voCXb2Zez-A4LkmgxlDazkJEpl=s0-d "V \ infty n [P, T \: constant]")
![\frac{V}{n} = konstanta \: [P, T \: konstan[/latex</p> <p style="text-align: center;">[latex]V_m = konstanta \: [P, T \: konstan]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_skPLkdA7YaKN_37zZetoW6oM3JhvmJffu-ec2VLhUGA8ZR4St9H5HGYf6G9_i4vPGG96ZWvbMlmpL4NKO-new7W6QR3zjohsk8eGjDjryyqg8mW7CFC7HLqlFYbuIPvlkkJz8fBMEgPtvL346dnAJpx-AV-R-Fh2EGtcDEQl2MznZXjH3wkLtMiKDypBdnm7nkqyhqWnGP3qMm0gljapLcvUIm_EELcWwL8cymSGUzTOMj_kLDi9xe2yG-LqOb_Eav2YJhs7aDC8n8V9aLt_WWggEfmfsKerkUFq7nh2ahtNbtL8mwgowfaWuNPS00TaMBoiQA1xv2PHHljAV5ZtgHZTVRckTeZVRE6q8vr3c=s0-d "\ Frac {V} {n} = constants \: [P, T \: constant [/ latex </ p> <p style = \"text-align: center;\"> [latex] V_m = constant \: [P, T \: constant]")
In the STP state (P = 1 atm, T = 273 K), V m ideal gas = 22.414 L / mol
In the case of RTP / ATP (P = 1 atm, T = 298 K), V m ideal gas = 24 L / mol
In certain circumstances, an ideal gas law applies:
Where R is the gas constant, R = 0.08206 L ∙ atm / mol ∙ K = 8.314 J / mol ∙ K
In the equation of the reaction, the reaction coefficient is known, that is, the number on the left of the molecular formula for multiplying all the atoms in the molecular formula. The comparison of the reaction coefficients can be interpreted as the mole ratio of the substances in the reaction. In each of the reactants and products, it is written in the form of the substance (s (solid), l (liquid), g (gas), or aq (solution with water solvent)) in brackets to the right of each molecular formula.
Example of equivalent chemical equation:
Example of steps equalizing the reaction equation:
1.
2.
3.
4.
Answer:
Molar and Molar Mass Concepts (})
In SI systems, one mole is defined as the sum of the material composed of entities (atoms, molecules, or other particles) a sum of the atoms in 12 grams of carbon-12. The value of the number of atoms is 6.022 × 10 23 called the Avogadro number, N A.The molar mass,}, is defined as the mass of 1 mol entity (atom, ion, molecule, unit of formula) of matter. The unit of the molar mass (}) is a gram / mol.
Stoichiometric Material: Mass relation, number of moles, and number of atoms of elements (Source: Chang, Raymond, 2010. Chemistry (10th edition) New York: McGraw Hill)
Empirical Formulas and Molecular Formulas
The empirical formula is the simplest integer ratio of the number of moles of each element in a compound. The molecular formula represents the true number of moles of each element in 1 mole of the compound. The molecular formula may be identical to the empirical formula or an integer multiple of the empirical formula. For example, phosphoric acid (H 3 PO 4 ) has a molecular formula and an identical empirical formula. Glucose has a molecular formula C 6 H 12 O 6 which is a folding of 6 times its empirical formula, CH 2 O.
Molecular formula ≡ (empirical formula) n
} Molecular formula = n ×} empirical formula , n = 1, 2, 3, ...
Basic Stoichiometric Solution
The term "concentration" of the solution expresses the amount of solute dissolved in a certain amount of solvent or a certain amount of solution. The concentration of the solution can be expressed in molarity. Molarity (M) is defined as the number of moles of solute per liter of solution.Basic Ideal Gas Stoichiometry
The molar volume, V m , is defined as the volume of 1 mol entity (atom, ion, molecule, unit of formula) of matter. The unit of the molar volume (V m ) is L / mol.In the case of RTP / ATP (P = 1 atm, T = 298 K), V m ideal gas = 24 L / mol
In certain circumstances, an ideal gas law applies:
Writing and Equating Chemical Reaction Equations
The chemical reaction equation is a statement written with a molecular formula that provides information on the identity and quantity of substances involved in a chemical or physical change . All reacting substances, called reactants, are placed to the left of the arrow, whose direction of the arrow to the right refers to the product, ie all the substances produced from the reaction.In the equation of the reaction, the reaction coefficient is known, that is, the number on the left of the molecular formula for multiplying all the atoms in the molecular formula. The comparison of the reaction coefficients can be interpreted as the mole ratio of the substances in the reaction. In each of the reactants and products, it is written in the form of the substance (s (solid), l (liquid), g (gas), or aq (solution with water solvent)) in brackets to the right of each molecular formula.
Example of equivalent chemical equation:
Example of steps equalizing the reaction equation:
1.
2.
3.
4.
Stoichiometry Reaction
In chemical reactions, the amount of reacting reactants is sometimes incompatible with the stoichiometric amount of the reaction (not in accordance with the coefficient ratio of the equivalent equation). Therefore, there will be reactants that have reacted first compared to other reactants. The reactants that remain after reacting are called excess reagents. The out-of-date reactant is called a limiting reagent. After the barrier reagents are exhausted, no more reaction products are formed. Thus, the number of limiting reagents determines the amount of product produced.Sample Stoichiometric Problem
Alkali metals (Group 1) react with halogens (Group 17) to form ionic compounds of metal halides. How many grams of potassium chloride formed from a reaction of 5.25 L of chlorine gas at a pressure of 0.950 atm and a temperature of 293 K with 17.0 g of potassium?Answer:
Are there any factors that influence stoichiometry? If any please explain to me
BalasHapusYes it have 6 factors :
Hapus1. Concentration of Reactants
A higher concentration of reactants leads to more effective collisions per unit time, which leads to an increasing reaction rate (except for zero order reactions). Similarly, a higher concentration of products tends to be associated with a lower reaction rate. Use the partial pressure of reactants in a gaseous state as a measure of their concentration.
2. Temperature
Usually, an increase in temperature is accompanied by an increase in the reaction rate. Temperature is a measure of the kinetic energy of a system, so higher temperature implies higher average kinetic energy of molecules and more collisions per unit time. A general rule of thumb for most (not all) chemical reactions is that the rate at which the reaction proceeds will approximately double for each 10°C increase in temperature. Once the temperature reaches a certain point, some of the chemical species may be altered (e.g., denaturing of proteins) and the chemical reaction will slow or stop.
3. Medium or State of Matter
The rate of a chemical reaction depends on the medium in which the reaction occurs. It may make a difference whether a medium is aqueous or organic; polar or nonpolar; or liquid, solid, or gaseous. Reactions involving liquids and especially solids depend on the available surface area.
For solids, the shape and size of the reactants makes a big difference in the reaction rate.
4. Presence of Catalysts and Competitors
Catalysts (e.g., enzymes) lower the activation energy of a chemical reaction and increase the rate of a chemical reaction without being consumed in the process. Catalysts work by increasing the frequency of collisions between reactants, altering the orientation of reactants so that more collisions are effective, reducing intramolecular bonding within reactant molecules, or donating electron density to the reactants. The presence of a catalyst helps a reaction to proceed more quickly to equilibrium. Aside from catalysts, other chemical species can affect a reaction. The quantity of hydrogen ions (the pH of aqueous solutions) can alter a reaction rate. Other chemical species may compete for a reactant or alter orientation, bonding, electron density, etc., thereby decreasing the rate of a reaction.
5. Pressure
Increasing the pressure of a reaction improves the likelihood reactants will interact with each other, thus increases the rate of the reaction. As you would expect, this factor is important for reactions involving gases, and not a significant factor with liquids and solids.
6. Mixing
Mixing reactants together increases their ability to interact, thus increases the rate of a chemical reaction.
in this post "Avogadro's law states that at certain pressures and temperatures and fixed, the volume of the gas is directly proportional to the amount of gas" please explain more and what mean about it?
BalasHapusDefinition of Avogadro's Law
HapusAvogadro's Law (sometimes referred to as Avogadro's hypothesis or Avogadro's principle) is a gas law; it states that under the same pressure and temperature conditions, equal volumes of all gases contain the same number of molecules. The law is named after Amedeo Avogadro who, in 1811, hypothesized that two given samples of an ideal gas—of the same volume and at the same temperature and pressure—contain the same number of molecules; thus, the number of molecules or atoms in a specific volume of ideal gas is independent of their size or the molar mass of the gas. For example, 1.00 L of N2 gas and 1.00 L of Cl2 gas contain the same number of molecules at Standard Temperature and Pressure (STP).
Avogadro's Law is stated mathematically as:
Vn=k
V is the volume of the gas, n is the number of moles of the gas, and k is a proportionality constant.
As an example, equal volumes of molecular hydrogen and nitrogen contain the same number of molecules and observe ideal gas behavior when they are at the same temperature and pressure. In practice, real gases show small deviations from the ideal behavior and do not adhere to the law perfectly; the law is still a useful approximation for scientists, however.
Give an example in a chemical reaction, the amount of reactant reactant sometimes does not correspond to the number of stoichiometric reactions (not in accordance with the coefficient ratio of the equivalent equation)?
BalasHapusLead (IV) hydroxide and sulfuric acid react as shown below. Balance the reaction.
HapusPb(OH
)
4
+
H
2
S
O
4
→Pb(S
O
4
)
2
+
H
2
O
Pb(OH)4+H2SO4→Pb(SO4)2+H2O
SOLUTION
Start by counting the number of atoms of each element.
UNBALANCED
Element
Reactant (# of atoms)
Product (# of atoms)
Pb
1
1
O
8
9
H
6
2
S
1
2
The reaction is not balanced; the reaction has 16 reactant atoms and only 14 product atoms and does not obey the conservation of mass principle. Stoichiometric coefficients must be added to make the equation balanced. In this example, there are only one sulfur atom present on the reactant side, so a coefficient of 2 should be added in front of
H
2
S
O
4
H2SO4
to have an equal number of sulfur on both sides of the equation. Since there are 12 oxygen on the reactant side and only 9 on the product side, a 4 coefficient should be added in front of
H
2
O
H2O
where there is a deficiency of oxygen. Count the number of elements now present on either side of the equation. Since the numbers are the same, the equation is now balanced.
Pb(OH
)
4
+2
H
2
S
O
4
→Pb(S
O
4
)
2
+4
H
2
O
Pb(OH)4+2H2SO4→Pb(SO4)2+4H2O
BALANCED
Element
Reactant (# of atoms)
Product (# of atoms)
Pb
1
1
O
12
12
H
8
8
S
2
2
Balancing reactions involves finding least common multiples between numbers of elements present on both sides of the equation. In general, when applying coefficients, add coefficients to the molecules or unpaired elements last.
A balanced equation ultimately has to satisfy two conditions.
The numbers of each element on the left and right side of the equation must be equal.
The charge on both sides of the equation must be equal. It is especially important to pay attention to charge when balancing redox reactions.
How do I calculate the volume of a solution?
BalasHapuscalculated as mass/volume. This ratio can be useful in determining the volume of a solution, given the mass or useful in finding the mass given the volume. In the latter case, the inverse relationship would be used.
HapusVolume x (Mass/Volume) = Mass
Mass x (Volume/Mass) = Volume
what often mistake we made in stoichiometry to calculate?
BalasHapusNot carefull.
HapusNot balance the equation. Not
Convert units of a given substance to moles.
Dont using the mole ratio, not calculate the moles of substance yielded by the reaction.
Not convert moles of wanted substance to desired units.
form of the substance (s (solid), l (liquid), g (gas), or aq (solution with water solvent)), can it make problem in stoikiometry?
BalasHapusTher may be no problem with the stoichiometric search process or the answer,Because since its function is merely to explain that it includes s(solid), l(liquid), g(gas), or aq(solution with water solvent)
Hapushow to Writing and Equating Chemical Reaction Equations
BalasHapus1. Count the atoms of each element in the reactants and the products
Hapus2. Use coeffisients place them in front of the compounds as needed