A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy without itself being consumed by the reaction.
2022
DP Chemistry Practical Guide
Dission Questions
Why are the burette and the pipette rinsed with the solution with which these are filled?
Answer:
OOO
Explanation:
OOOOOO
balance the chemical
reaction by providing the
correct coefficient
Answer:
2HBr + Ba(OH)2 ____ BaBr2 + 2H2O
The numbers placed in front of formulas to balance equations
Pleaseee help pleaseee!!!
NaClO₃ ⇒ NaCl + O₂ ⇒ unbalanced
1. O : left 3, right 2
give coefficient left 2, right 3
2NaClO₃ ⇒ NaCl + 3O₂
2. Na and Cl : left 2, right 1
give coefficient right 2
2NaClO₃ ⇒ 2NaCl + 3O₂ ⇒ balanced
6. A sample of a gas at 77°C and 1.33 atm occupies a volume of 50.3 L. How many moles of the gas are present? (Hint: Since moles have been asked, which equation has the moles listed in the equation. Use that to solve this problem).
The number of moles of the gas at 77°C and 1.33 atm occupies a volume of 50.3 L is 2.35 moles. It can found with the help of Ideal gas equation.
What is Ideal Gas equation ?The ideal gas equation is formulated as : PV = nRT.
In this equation, P refers to the pressure of the ideal gas, V is the volume of the ideal gas, n is the total amount of ideal gas that is measured in terms of moles, R is the universal gas constant, and T is the temperature.
Given ;
Pressure = 1.33 atmVolume = 50.3 ltrTemperature = 77 (+273 k) = 350KWe know ;
Gas constant (R) = 0.081 L atm/mol KFormula used ;
n = PV / RT
n = 1.33 x 50.3 / 0.081 x 350k
= 2.35 moles.
Hence, The number of moles of the gas at 77°C and 1.33 atm occupies a volume of 50.3 L is 2.35 moles
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Barium nitrate (Ba(NO3)2) reacts with sodium chloride (NaCl) in a double replacement (displacement) reaction, shown below.
Ba(NO3)2(aq)+NaCl(aq)-->???
How many grams of barium salt are produced when a solution containing 21.7 g of Barium nitrate is mixed with a solution containing excess sodium chloride?
Use 261.34 as the molar mass for barium nitrate. Round to three significant digits.
Answer:
you know that they will be a displacement reaction that will form a barium salt:
Ba(NO3)2+ 2NaCl--> BaCl2 + 2NaNO3
So now that we have that formula and the molecular weight we can determine how much salt will be made. So here we convert the grams to moles
(42.3g Ba(NO3)2)*(1 mole/261.34g) = 0.16185 mol
In the molecular formula we know that 1 mole of Barium nitrate will create 1 mole of Barium chloride, so in this case (in a perfect world) you should get 0.16185 mole of barium chloride (208.23 g/mol) that we then have to convert to grams.
(0.16185 mol BaCl2) * ( 208.23 g/mol) = 33.7037 g of Barium Chloride (rounded to 3 significant digits = 33.7g)
Hydrogen and iodine vapour exist in equilibrium with hydrogen iodide at a constant temperature in a gas syringe.
H2 + I2
2HI
Which of the following will increase when the pressure is increased at constant temperature? [Assume that the mixture shows ideal behavior.]
The pressure has no effect on the equilibrium constant.
What is Equilibrium ?Equilibrium is a state when the forward reaction rate is equal to the backward reaction rate .
The equation given is
H₂ + I₂ ⇄ 2HI
The Equilibrium constant depends only upon temperature and nature of reaction ,
It is independent of catalyst presence , initial concentration of reactants,and pressure.
The pressure has no effect on the equilibrium constant.
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diffrentiate between equation and chemical formula
A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side with a plus sign between the entities in both the reactants and the products and an arrow that points towards the products, and shows the direction of the reaction. The coefficients next to the symbols and formulae of entities are the absolute values of the stoichiometric numbers. The first chemical equation was diagrammed by Jeen Beguin in 1615.
A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus and minus signs.
Hope this helps you!
Answer:
Explanation:
Chemical Formula:Represents the composition of a substance or compoundUses symbols and subscripts to indicate the types and numbers of atoms in a moleculeExample: H2O represents the chemical formula for waterChemical Equation:Represents a chemical reactionShows the reactants and products involved in the reactionUses chemical formulas and symbolsReactants are on the left side, products on the right side, separated by an arrowExample: 2H2 + O2 → 2H2O represents the reaction of hydrogen gas and oxygen gas to form waterIn summary:Formula describes composition, equation describes a reactionFormula uses subscripts for atom count, equation uses symbols and arrowsSort the length measurements in increasing order of magnitude from smallest to largest.
The length measurements in increasing order of magnitude from smallest to largest is Nanometer, micrometer, centimeter, decimeter, dekameter, kilometer.
What is Measurement ?Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events.
Measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind.
Hence, Among the given length measurements, The increasing order of magnitude from smallest to largest is Nanometer, micrometer, centimeter, decimeter, dekameter, kilometer.
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The absolute molar entropies of O2 and N2 are 205 J K-1 mol -1 and 192 J K-1 mol-1, respectively, at 25°C. What is the entropy of a mixture of 2.4 moles of 02 and 9.2 moles of N2 at the same temperature and pressure?
The entropy of a mixture is 96.44J K-1 mol -1
The absolute molar entropies of O2= 205 J K-1 mol -1 The absolute molar entropies of N2=192 J K-1 mol -1 Moles of O2 present(m)=2.4Moles of N2 present(n)=9.2The formula for calculating the entropy of a mixture-
Δ[tex]S_{mix} =[/tex][tex]-nR(X_{O2} ln_{XO2} +X_{N2} lnX_{N2})[/tex]
X=mole fraction
total no. of moles(t)=m + n
=2.4+9.2
=11.6 moles
now substituting the values-
entropy of mix=-11.6R(2.4/11.6 + 9.2/11.6)
=11.6R
( R=8.314 ) =11.6×8.314
=96.44J K-1 mol -1
hence, The entropy of a mixture is 96.44J K-1 mol -1
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Explain how you would determine the charge of a metal, a non
metal and a transition metal for an ion within a compound. Be
prepared to provide the charge of an element on the periodic
table from each of these categories.
Answer:
In order to determine the charge of these elements you'll have to look at their placement in the periodic table by group number.
Explanation:
To further explain this, there is 18 groups of the periodic table. These groups include:
Group 1: The alkali metals have a 1+ charge for their entire group.
For example: Sodium would have a charge of 1+.
Group 2: The earth alkali metals all have a charge of 2+. For example Mg has a charge of 2+.
Group 3-12: The transitions metals are a little harder to figure the charge of each, if given the compound they are bonded with you can use that to figure it out but only a few have distinct charges. Such as Ag (Silver) only have a 1+ charge. If you are still trying to figure the charge, try making an electron configuration to figure out it's spare electron count or charge.
Group 13: These elements in group 13 have a typical charge of 3+. For example Al has a charge of 3+.
Group 14: These elements in group 14 have a typical charge of 4+. For example Carbon has a charge 4+
Group 15: These elements start the shift towards a negative charge in the table, so for group 15 the elements have a 3- charge. For example Nitrogen has a 3- charge.
Group 16: These elements continue with a negative in group 16 with a negative charge of 2-. For example Oxygen's charge is 2-.
Group 17: The halogen elements in group 17 have a charge of 1-. For example Chlorine has a charge of -.
Group 18: The noble gases in group 18 do not have a charge because they are some of the most stable elements so they're not looking to gain or lose an electron (That is what a charge is basicaly). So, they're charge is none.
How many atoms are in 2.17 moles of strontium?
Answer: I think 82.46
Explanation: The atomic number for strontium, or Sr on the periodic table, is 38. With knowing the atomic number, I multiplied that by the number of moles given.
38 × 2.17 = 82.46
I hope this helps!!
The number of atoms present in 2.17 moles of strontium are [tex]1.306774 \times 10^{24}[/tex].
An atom is the smallest indivisible unit of a chemical element that retains the chemical properties of that element. It is the basic building block of matter.
To determine the number of atoms in a given number of moles, we can use Avogadro's number, which is approximately [tex]6.022 \times 10 ^{24}[/tex] atoms per mole.
In this case, we have 2.17 moles of strontium. To find the number of atoms, we multiply the number of moles by Avogadro's number:
Number of atoms = [tex]2.17 moles\times6.022\times 10^{23}[/tex][tex]atoms/mole[/tex]
On calculating this expression:
Number of atoms =[tex]1.306774 \times 10^{24}[/tex]
Therefore, there are approximately [tex]1.306774 \times 10^{24}[/tex] atoms in 2.17 moles of strontium.
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What does the prefix cis-in the name of a stereoisomer indicate about the
functional groups?
How many grams of copper
Question 4 of 15
A compound with the empirical formula CH₂ has a molar mass of 42 g/mol. What is the molecular formula for this compound?
molecular formula:
3CH₂
Attempt 1
Incorrect
(CH₂)n=42
(14)n=42
n=3
C₃H₆
You are working with a concentrated solution of ammonium hydroxide. Which
piece of safety equipment is most important to have on hand?
Rubber gloves and other chemical resistant protective clothing are necessary when handling concentrated ammonium hydroxide.
Why it is necessary to handle concentrated solution of ammonium hydroxide with care ?Ammonia is an irritant and corrosive to the skin, eyes, respiratory tract and mucous membranes. May cause severe chemical burns to the eyes, lungs and skin.The extent of injury produced by exposure to ammonia depends on the duration of the exposure, the concentration of the liquid or vapor and the depth of inhalation.
Hence, Rubber gloves and other chemical resistant protective clothing are necessary when handling concentrated ammonium hydroxide.
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Explain the term 'end point'?
What do you mean by a 1.0 M solution?
Answer:
According to me end point is the end of a reaction
What is the number of elements in 2Ca(OH)2
What would most likely happen when a metal is heated?
It will melt.
It will solidify.
Its temperature will decrease.
Its particles will move slower.
Answer: it is A i took the test i got it right
Explanation: i took the test
What is the concentration of acetic acid if three 65.0 mL samples of actic acid were neutralized with 16.8 mL, 18.2 mL, and 17.35 mL of 0.5.00 M KOH. (Hint: KOH and acetic acid react in a 1 to 1 mole ratio)
M₁V₁=M₂V₂
65 x M₁ = 16.8 x 0.5
M₁ = 0.129
65 x M₁ = 18.2 x 0.5
M₁ = 0.14
65 x M₁ = 17.35 x 0.5
M₁ = 0.133
Average = 0.129 + 0.14 + 0.133 = 0.134 M
After scientists use a careful process to gather evidence and establish scientific facts, which step most likely occurs next in the scientific process? conducting experiments testing new conditions Ostudying new topics determining explanations After scientists use a careful process to gather evidence and establish scientific facts , which step most likely occurs next in the scientific process ? conducting experiments testing new conditions Ostudying new topics determining explanations
Answer:
Conducting Experiments
A tank holds 22.1 L of oxygen ( O2 ) at a pressure of 18.0 atm . What is the final volume, in liters, of this gas when it is released at a pressure of 2.90 atm with no change in temperature and amount of gas.
The final volume of gas will be 137.17L .
According to ideal gas equation , PV=nRT , where P is pressure of gas , V is volume of gas , n is moles of gas , R is universal gas constant and T is the temprature of gas.
Now , according to the que at initial and final stage the temprature and amount of gas stays constant , so we would simply equate the initial PV to the final PV.
⇒[tex]P_{i} V_{i} = P_{f} V_{f} \\[/tex]
where [tex]P_{i}[/tex] ans [tex]V_{i}[/tex] are the initial pressure and volume of the gas and [tex]P_{f}[/tex] and [tex]V_{f}[/tex] are the final pressure and volume of the gas .
Here we have to find final volume of gas .
So , putting all values in above eq we get
18 x 22.1 = 2.9 x [tex]V_{f}[/tex]
⇒ [tex]V_{f}[/tex] = 137.17 L
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1. For CCl4, upload a photo including the following: (1) work arriving at total # valence electrons
(2) hand drawn Lewis structure (3) molecular model (4) signature(s) and (5) date.
Work arriving at total valence electrons are 24
The valence electron is an electron in the outer shell associated with an atom, and that can participate in the formation of a chemical bond
For a main-group element, a valence electron can exist only in the outermost electron shell; for a transition metal, a valence electron can also be in an inner shell.
Lewis structures, also known as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDS), are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule.
Calculating the work arrival at total valence electrons
We know 1 bond contains
2 valence electrons
Here CCl4 contains 4 bonds that is 8 valence electrons
Therefore ,
Total valence electrons are 32
Now valence electrons remain after bond formation =
32 - 8
=24 valence electrons
A molecular model is a physical model of an atomistic system that represents molecules and their processes
Molecular image and lewis hand drawn structure is as shown below
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12. Consider the system PCl3(g) + Cl2(g) PCl5(g) at equilibrium at 25°C, for which H° = –92.5kJ at 25°C. When some Cl2(g) is added at constant volume and temperature, the ratio of the partial pressure of PCl5 to the partial pressure of PCl3 wil
For a system PCl3(g) + Cl2(g) PCl5(g) at equilibrium at 25°C, for which H° = –92.5kJ at 25°C, the ratio of the partial pressure of PCl5 to the partial pressure of PCl3 is will increase
What is the ratio of the partial pressure of PCl5 to the partial pressure of PCl3?Generally, the equation for chemiecal reaction is mathematically given as
PC3 (g) + C₁₁₂ (g) = PC15 (g) 3
Assuming the addition of some Cl2 gas. The reaction will shift to the right at the invariant volume temperature, maintaining equilibrium. This results in a rise in P9Cl5(g) and a fall in PpCl3(g).
PpCl (g) /PpCl (g) will increase
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The ratio of the partial pressure of PCl₅ to the partial pressure of PCl₃ is will increase for a system PCl₃ (g) + Cl₂ (g) --> PCl₅ (g) at equilibrium at 25°C, for which H° = –92.5kJ at 25°C when some Cl₂ (g) is added at constant volume and temperature.
What is the ratio of the partial pressure of PCl₅ to the partial pressure of PCl₃?
Generally, the equation for chemical reaction is mathematically given as ;
PCl₃ (g) + Cl₂ (g) --> PCl₅ (g)
Assuming the addition of some Cl₂ gas,
The reaction will shift to the right at the constant volume and temperature, maintaining equilibrium.
This results in a rise in PCl₅ (g) and a fall in PCl₃(g).
Hence, the ratio of the partial pressure of PCl₅ to the partial pressure of PCl₃ is will increases
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Write and balance the equation for the combustion of the fatty acid lauric acid, (C12H24O2)
.
Express your answer as a chemical equation. Identify all of the phases in your answer.
The combustion of lauric acid is shown as CH3(CH2)10COOH(s) + 18O2(g) -----> 12H20(l) + 12CO2(g)
What is combustion?In a combustion reaction, a substance is burnt in oxygen. If the substance is an organic compound a the case is here, the products are carbon dioxide and hydrogen.
No the equation of the combustion of lauric acid is shown as;
CH3(CH2)10COOH(s) + 18O2(g) -----> 12H20(l) + 12CO2(g)
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Which hybrid orbitals overlap to form the sigma bonds between the indicated atoms in xanthine?
Correct Answer is B
Answer:
C.) Csp² - Nsp³
Explanation:
Because the carbon has only 3 unique bonds, the conformation of the carbon should be Csp² (s + p + p). While the nitrogen also has only 3 bonds, making up 3 orbitals, it also has a lone pair of electrons. These electrons also take up one orbital. Therefore, the conformation of nitrogen is Nsp³ (s + p + p + p).
The hybrid orbitals overlap to form the sigma bonds between the indicated atoms in xanthine is Csp2 and Nsp3.
What is hybridization?Hybridization is defined as the concept of the mixing of the atomic orbitals for the formation of new hybrid orbitals which are suitable for the pairing of electrons in forming chemical bonds in valence bond theory. And the orbital formed by the hybridization are termed as hybrid orbitals.
Since the carbon atom form one single bond with hydrogen atom and one pi bond with nitrogen bond, so the conformation of carbon atom is Csp2. On the other hand, nitrogen also form one single bond and a pi bond, so it also contribute three hybrid orbital. Since it have one lone pair of nitrogen so they take one orbitals. Therefore, the conformation of nitrogen atom is Nsp3.
Thus, we concluded that the hybrid orbitals overlap to form the sigma bonds between the indicated atoms in xanthine is Csp2 and Nsp3.
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How many moles of O2 are consumed when 2.10 mol of magnesium burns?
1.05 moles of oxygen gas are consumed in the reaction when 2.10 mol of magnesium burns.
What are moles?A mole is defined as [tex]6.02214076 × 10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
We are given:
Moles of magnesium = 2.10 mol
For the given chemical reaction:
2Mg + O₂ → 2MgO.
By Stoichiometry of the reaction:
2 moles of magnesium react with 1 mole of oxygen gas.
So, 2.10 moles of magnesium will react with = [tex]\frac{1}{2}[/tex] X2.10 =1.05 moles
Hence, 1.05 moles of oxygen gas are consumed in the reaction.
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The physical matter of which living or nonliving things are composed is called a ___
(Fill in the blank one word)
100 POINTS TO WHO EVER IS CORRECT!
Answer:
Substance
Explanation:
Any physical matter despite of living or non living things are composed by a set of molecules or atoms commonly known as substance
On specific living things are composed of biomolecules or cells where as non living things are composed of molecules and atoms
Answer:
Substances
Physical matters are divided into 3 states
solid stateLiquid stateGaseous stateAs per randomness of particles the order is
Gaseous>Liquid>SolidA dunk tank hold 30,533 moles of water? How many grams of water are in the tank?
What type of reaction is represented by the following equation?
Mg(OH)2 (aq) + 2 HCl (aq) --> MgCl2 (aq) + 2 H2O (l)
Answer: Double replacement reaction
Explanation:
If you have the following chemical equation and you begin balancing it as such,
C5H10 + O2 --> 5CO2 + 5H2O
How many oxygens do you have on the product side at this point in the balancing?
Answer:
15 oxygens
Explanation:
Given the partially balanced reaction: [tex]\text{C}_{\text{5}}\text{H}_{\text{10}}+\text{O}_{\text{2}} \rightarrow \text{5C} \text{O}_{2}}+\text{5H}_\text{2}\text{O}[/tex]
The subscripts (small number to the right of each element symbol) are the number of atoms of the element within each compound/molecule, and the coefficients (numbers in front of each compound) represent the number of that molecule involved in one full reaction (if the equation were balanced).
The product side of the reaction is on the right of the arrow.
To determine the total number of Oxygens on the product side, we need to identify how many Oxygens are in each molecule (the subscript on the Oxygen), and then multiply times the number of that molecule that would be involved (Coefficient of the compound containing Oxygen). There are multiple compounds on the right side of the equation that contain Oxygen, so we'll need to add together the number of Oxygens each part contributes.
[tex]\text{C}_{\text{5}}\text{H}_{\text{10}}+\text{O}_{\text{2}} \rightarrow \bold{5}\text{C} \bold{O_{2}}+\bold{5}\text{H}_\text{2}\bold{O}[/tex]
[tex]\text{\# reactant-side Oxygens}=\bold{5}\text{C} \bold{O_{2}}+\bold{5}\text{H}_\text{2}\bold{O}\\=5 \text{ CO}_{\text{2}}\text{ molecules} *\frac{\text{2 Oxygens}}{\text{1 CO}_{\text{2}}\text{ molecule}}+5 \text{ H}_{\text{2}}\text{O molecules} *\frac{1\text{ Oxygen}}{\text{1 H}_{\text{2}}\text{O molecule}}\\=10\text{ Oxygens}+5\text{ Oxygens}\\=15\text{ Oxygens}[/tex]