A different brand of iron tablet was analysed by Hitration with 0.0093 mol.L" potassium
dichromate via the reaction listed below;
Cr2O72- + 6Fe2+ + 14H+ + 2Cr3+ + 6Fe3+ + 7H20
In this experiment 4 tablets were crushed and dissolved in 200 cm3 of dilute acid. 25cm3
of this solution was used in the titration. The results of the titrations were as follows;
Titration Volume dichromate (cm)
1
33.0
2
32.05
3
32.15
4
32.10
Calculate the concentration of iron used in the titration (4 dp).
C1V1/C2V2 = n/n2
Answers
The concentration of iron used in the titration : 0.009 M
Further explanationGiven
Reaction
Cr₂O₇²⁻ + 6Fe²⁺ + 14H⁺ ⇒ 2Cr³⁺ + 6Fe³⁺ + 7H₂O
0.0093 mol/L potassium dichromate
200 cm³ of dilute acid, 25cm³ was used in the titration.
Required
the concentration of iron
Solution
Titration formula
C₁V₁n₁=C₂V₂n₂⇒ From equation : n₁=6n₂(1=Cr₂O₇, 2=Fe)
titration average : 33+32.05+32.15+32.1 / 4 = 32.325 cm³(ml)
25 cm³ of iron solution used in titration :
[tex]\tt V_1=32.325~ml\\\\V_2=25~ml\\\\C_1=0.0093~M\\\\\\\\C_1.V_1.n_2=C_2.V_2.n_1\\\\0.0093\times 32.325\times 6=C_2\times 25\times 1\\\\C_2=0.07215~M[/tex]
Dilution(25 ml from 200 ml iron solution)
[tex]\tt C_2.V_2=C_1.V_1\\\\0.007215\times 25=C_1\times 200\\\\C_1=0.009~M[/tex]
Related Questions
Which material would get electrons from the source to the load the fastest
Answers
Answer:
Copper
Explanation:
Because copper conducts a lot of electricity, and gets the most electrons
Copper is a metal with the ability to conduct electricity, so copper wires are often used in small household appliances. The ability to
conduct electricity is a drag and drop answer here property of copper. Iron, on the other hand, reacts with oxygen to form iron oxide, also
known as rust. The ability of iron to rust is a drag and drop answer here property of the metal As scientists characterize certain metals, they
investigate physical properties like drag and drop answer here and chemical properties like drag and drop answer here.
Answers
Answer:
physical property
Chemical property
melting point
Reactivity with a strong acid
Explanation:
The ability to conduct electricity is a physical property of copper. Most electrical cables are made of copper owing to its high electrical conductivity.
The rusting of iron is a chemical reaction. Rust is actually hydrated iron III oxide. Hence it is a chemical property of iron.
The melting points of metals can be used to classify them. The greater the density of metals, the higher their melting point.
The ability of metals to react with acids separates metals into highly reactive, moderately reactive and unreactive metals.
Copper shows physcal property & iron shows chemical property.
What are physical and chemical properties?Physical properties are those properties which are seen by the eye due to change in the outermost appearance, whereas chemical properties are those which are shown due to change in the internal composition.
In the question, it is given that copper metal has a ability to conduct electricity and this property of metal is the physical property, as due to conduction their identity is not changing.
It is also given that iron is showing rusting due to the formation of iron oxide, so it a chemical property as identity of iron changes.
So, scientists characterize certain metals, they investigate physical properties like melting point, conductivity, density, etc. and chemical properties like reactivity with acid, base, oxygen, etc.
Hence, the ability to conduct electricity is a physical property of Cu and the ability of iron to rust is a chemical property.
To learn more about physical and chemical properties, visit the below link:
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An atom has a mass number of 9 and 5 neutrons. What is its atomic number? A 19 B. 14 O c.4 D. 11 SN
Answers
Answer:
[tex]\boxed {\boxed {\sf C. \ 4}}[/tex]
Explanation:
First, define some important terms.
Mass number: the sum of the nucleons (protons and neutrons) Atomic number: the number of protonsWe know the mass number is 9. So, the sum of protons and neutrons is 9.
[tex]mass \ number =9[/tex][tex]protons + neutrons = 9[/tex]We also know the atoms has 5 neutrons. Therefore, the rest must be protons.
[tex]protons + 5 \ neutrons =9[/tex]Subtract the 5 neutrons from the overall mass number of 9.
[tex]protons = 9- 5 \ neutrons \\[/tex][tex]protons=4[/tex]There are 4 protons, so the atomic number is also 4. This atom is beryllium.
When the volume of a gas is
changed from 3.6 L to 15.5 L, the
temperature will change from
°C to 87°C.
Assume that the number of moles and the
pressure remain constant.
Be sure to notice that temperatures are
given in °C!
Answers
Initial temperature = -189.4 °C
Further explanationGiven
the volume of a gas is changed from 3.6 L to 15.5 L
final temperature = 87 °C = 87+ 273 = 360 K
Required
initial temperature
Solution
Charles's Law
When the gas pressure is kept constant, the gas volume is proportional to the temperature
[tex]\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]
[tex]\tt T_1=\dfrac{V_1.T_2}{V_2}\\\\T_1=\dfrac{3.6\times 360}{15.5}\\\\T_1=83.6~K=-189.4^oC[/tex]
What element needs just a single extra electron to have the same electron configuration as helium?
Answers
Answer:
Hydrogen
Explanation:
Helium has an atomic number Z = 2, that is, it has 2 protons. Since it is electrically neutral it also has 2 electrons. Thus, the electron configuration of helium is 1s².
Hydrogen has an atomic number Z = 1, that is, it has 1 proton. Since it is electrically neutral it also has 1 electron. Thus, the electron configuration of hydrogen is 1s¹.
If hydrogen gains a single extra electron to form H¹⁻, it acquires the same electron configuration than helium.
g In this equation stands for the Rydberg energy, and stands for the principal quantum number of the orbital that holds the electron. (You can find the value of the Rydberg energy using the Data button on the ALEKS toolbar.) Calculate the wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron from an orbital with to an orbital with . Round your answer to significant digits.
Answers
The complete question is attached to this answer
Answer:
2.75 * 10^-5 m
Explanation:
The energy of the absorbed photon = ΔE
ΔE = - Ry (1/n^2 final - 1/n^2initial)
Given that Ry = 2.18 *10^-18 J
nfinal = 9
ninitial =8
ΔE = - 2.18 *10^-18 (1/9^2- 1/8^2)
ΔE = - 2.18 *10^-18 (0.0123 - 0.0156)
ΔE = 7.194 * 10^-21 J
But
ΔE =hc/λ
h = 6.6 *10^-34Js
c= 3 * 10^8 ms-1
λ= the unknown
λ= hc/ΔE
λ= 6.6 *10^-34 * 3 * 10^8/ 7.194 * 10^-21
λ= 2.75 * 10^-5 m
Which part of the immune system can be "trained" using vaccines?
Answers
Suppose 3.20 g of copper are reacted with excess nitric acid according to the given equation, and 6.32 g Cu(NO3)2 product are obtained.
Cu(s) + 4 HNO3 (aq) --> Cu(NO3)2 (aq) + 2 NO2 (g) + 2 H2O(l)
What is the theoretical yield of Cu(NO3)2? In g
What is the percent yield of Cu(NO3)2? In %
Answers
Answer:
1. 9.45 g
2. 66.9%
Explanation:
The balanced equation for the reaction is given below:
Cu(s) + 4HNO3(aq) —> Cu(NO3)2(aq) + 2NO2(g) + 2 H2O(l)
Next, we shall determine the mass of Cu that reacted and the mass of Cu(NO3)2 produced from the balanced equation. This can be obtained as follow:
Molar mass of Cu = 63.5 g/mol
Mass of Cu from the balanced equation
= 1 × 63.5 = 63.5 g
Molar mass of Cu(NO3)2 = 63.5 + 2[14 + (3×16)]
= 63.5 + 2[14 + 48]
= 63.5 + 2[62]
= 63.5 + 124
= 187.5 g/mol
Mass of Cu(NO3)2 from the balanced equation = 1 × 187.5 = 187.5 g
Summary:
From the balanced equation above,
63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.
1. Determination of the theoretical yield of Cu(NO3)2. This can be obtained as follow:
From the balanced equation above,
63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.
Therefore, 3.20 g of Cu will react to produce = (3.20 × 187.5) / 63.5 = 9.45 g of Cu(NO3)2.
Thus, the theoretical yield of Cu(NO3)2 is 9.45 g.
2. Determination of the percentage yield of Cu(NO3)2.
Actual yield of Cu(NO3)2 = 6.32 g
Theoretical yield of Cu(NO3)2 = 9.45 g.
Percentage of the Cu(NO3)2 =?
Percentage yield = Actual yield /Theoretical yield × 100
Percentage yield of Cu(NO3)2 = 6.32/9.45 × 100
Percentage yield of Cu(NO3)2 = 66.9%
The theoretical yield of Cu(NO₃)₂ is 9.445 g
The percent yield of Cu(NO₃)₂ is 66.91%
From the question.
We are to determine the theoretical yield of Cu(NO₃)₂,
First and foremost, we will write the balanced chemical equation for the reaction properly
The balanced chemical equation for the reaction is
Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)
This means
1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂, 2 moles of NO₂ and 2 moles of H₂O
To determine the theoretical yield of Cu(NO₃)₂,
First, we will determine the number of moles of Cu that reacted
Mass of Cu = 3.20 g
Molar mass of Cu = 63.546 g/mol
From the formula
[tex]Number\ of\ moles =\frac{Mass}{Molar\ mass}[/tex]
∴ Number of moles of Cu = [tex]\frac{3.20}{63.546}[/tex]
Number of moles of Cu present = 0.050357 moles
The number of moles of Cu that reacted is 0.050357 moles
Since,
1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂
Then,
0.050357 moles of Cu will react with 0.201428 moles of HNO₃ to produce 0.050357 moles of Cu(NO₃)₂
∴ 0.050357 moles of Cu(NO₃)₂ will be produced during reaction
Now, for the theoretical yield of Cu(NO₃)₂
From the formula
Mass = Number of moles × Molar mass
Molar mass of Cu(NO₃)₂ = 187.56 g/mol
∴ Theoretical yield of Cu(NO₃)₂ = 0.050357 × 187.56
Theoretical yield of Cu(NO₃)₂ = 9.445 g
Hence, the theoretical yield of Cu(NO₃)₂ is 9.445 g
For the percent yield of Cu(NO₃)₂
[tex]Percent \ yield = \frac{Actual \ yield}{Theoretical \ yield } \times 100 \%[/tex]
From the question
Actual yield = 6.32 g
But,
Theoretical yield = 9.445 g
∴ Percent yield of Cu(NO₃)₂ = [tex]\frac{6.32}{9.445} \times 100\%[/tex]
Percent yield of Cu(NO₃)₂ = [tex]\frac{632}{9.445}\%[/tex]
Percent yield of Cu(NO₃)₂ = 66.91%
Hence, the percent yield of Cu(NO₃)₂ is 66.91%
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When the volume of a gas is
changed from 3.6 L to 15.5 L, the
temperature will change from
°C to 87°C.
Assume that the number of moles and the
pressure remain constant.
Be sure to notice that temperatures are
given in °C!
Answers
Answer:
-189.55°C
Explanation:
Given data:
Initial volume of gas = 3.6 L
Final volume of gas = 15.5 L
Initial temperature = ?
Final temperature = 87°C (87+273 = 360 K)
Solution:
The given problem will be solve through the Charles Law.
According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.
Mathematical expression:
V₁/T₁ = V₂/T₂
V₁ = Initial volume
T₁ = Initial temperature
V₂ = Final volume
T₂ = Final temperature
Now we will put the values in formula.
V₁/T₁ = V₂/T₂
T₁ = V₁T₂ /V₂
T₁ = 3.6 L × 360 K / 15.5 L
T₁ = 1296 L.K / 15.5 L
T₁ = 83.6 K
Kelvin to °C:
83.6 K - 273.15 = -189.55°C
name the group and period of an element having atomic number 21
Answers
Answer:
The element in question here is Scandium, with an atomic number of 21. It is situated in Group 3 and Period 4 of the Periodic Table.
Explanation:
Hope this helped!
1
MS-LS1-1, MS-LS1-2
Structure and
Function of Cells
-, -
1. Which of the following is not stated in the cell
theory?
A. Cells are the basic unit of structure and
function in all living things.
B. Animal cells are generally more complex
than plant cells.
C. All living things are composed of cells.
D. All cells are produced from other cells.
Ok
Answers
How many moles of copper are in 6,000,000 atoms of copper?
Answers
Answer: There will be 9.9632 × 10⁻¹⁸ moles of Copper in 6,000,000 atoms of Copper.
Are these synthesis decomposition single replacement or double replacement?
Answers
Answer:
1. Synthesis
2. Decomposition
3. Single replacement
4. Synthesis
5. Decomposition
6. Synthesis
Explanation:
Kind of a hard picture to look at but let me define each chemical reaction:
Synthesis:
a + b ---> ab In synthesis elements/compounds come together to form new compounds
Decomposition:
ab ---> a + b In decomposition a compound breaks down to form 2 elements/compounds
Single replacement:
a + bc ---> b + ac In a single replacement one element/compound takes the place of another element/compound.
Double replacement
ab + cd ---> ad + bc In a double replacement 2 compounds exchange different elements/compounds.
Now, let's go through the assignment
1. P + O2 --> P4O10 This is a synthesis reaction because the two elements (P and O) came together to form one compound.
2. HgO ---> Hg + O2 This is a decomposition reaction because HgO broke into separate elements Hg and O.
3. Cl2 + NaBr ---> NaCl + Br2 This is a single replacement reaction because chlorine (Cl) replaced the spot of bromine (Br) to bond with sodium (Na).
4. Mg + O2 ---> MgO This is a synthesis reaction because two elements (Mg and O) came together to form one compound.
5. Al2O3 ---> Al + O2 This is a decomposition reactions because Al2O3 broke into separate elements Al and O.
6. H2 + N2 ---> NH3 This is a synthesis reaction because two elements (H and N) came together to form one compound.
I hope this helps!!
- Kay :)
Given chemical equations are of following types which are given in serial order as synthesis,decomposition,replacement,synthesis,decomposition and synthesis reactions respectively.
1. It is a synthesis reaction because the two elements (P and O) came together to form one compound.
2. It is a decomposition reaction because HgO broke into separate elements Hg and O.
3. It is a single replacement reaction because chlorine (Cl) replaced the spot of bromine (Br) to bond with sodium (Na).
4. It is a synthesis reaction because two elements (Mg and O) came together to form one compound.
5. It is a decomposition reactions because aluminium oxide broke into separate elements Al and O.
6. It is a synthesis reaction because two elements (H and N) came together to form one compound.
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What type of reaction occurs between an element and a compound?
Answers
Answer:
exothermic reaction
Explanation:
because it occurs in the presence of heat
Read the word equation: “Propane gas plus oxygen gas produces __________.”
b) Convert the word equation to a chemical equation and complete the reaction. Be sure to balance
the chemical equation.
c) Record the balanced chemical equation on the Student Worksheet.
Answers
Answer:
Propane gas plus oxygen gas produces water and carbon dioxide.
Explanation:
This is the initial chemical equation: C3H8 + O2 = CO2 + H2O
This is the balanced chemical equation: C3H8 + 5 O2 = 3 CO2 + 4 H2O
C3H8 + O2 → CO2 + H2O
However, the above equation is not balanced. To balance it, we make use of coefficients to make the number of atoms of each element equal. The balanced equation is as follows:C3H8 + 5O2 → 3CO2 + 4H2O
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What is the mass percent of oxygen (0) in SO2?
32.1 g
A.
x 100%
16.0 g + 16.0 g
(16.0 g +16g)(6.02 x 1023)
B.
100 g
16.0 g
x 100%
(32.1 g + 16.0 g + 16.0 g)
D.
(16.0 g + 16.0 g)
X 100%
(32.1 g + 16.0 g + 16.0 g)
SUIRMIT
Answers
Answer:
D. (16.0 g + 16.0 g) × 100% / (32.1 g + 16.0 g + 16.0 g) = 49.9%
Explanation:
Step 1: Detemine the mass of O in SO₂
There are 2 atoms of O in 1 molecule of SO₂. Then,
m(O) = 2 × 16.0 g = 16.0 g + 16.0 g = 32.0 g
Step 2: Determine the mass of SO₂
m(SO₂) = 1 × mS + 2 × mO = 1 × 32.1 g + 2 × 16.0 g = 32.1 g + 16.0 g + 16.0 g = 64.1 g
Step 3: Detemine the mass percent of oxygen in SO₂
We will use the following expression.
m(O)/m(SO₂) × 100%
(16.0 g + 16.0 g) × 100% / (32.1 g + 16.0 g + 16.0 g) = 49.9%
Answer:
16.0 g + 16.0 g) × 100% / (32.1 g + 16.0 g + 16.0 g) = 49.9%
Explanation:
28. After 3 substances are mixed, an odor emits
a. chemical change
b. physical change
c. thermal energy is used
a do
Answers
Answer:
a. chemical change
Explanation:
A chemical change can cause an odor, however a physical change cannot, and the use of thermal energy will only make an object colder, not give it an odor.
Which electron dot diagram represents H2?
Answers
Answer:
H:H
Explanation:
In a double replacement reaction, the ions of two compounds exchange places in an aqueous solution to form two new compounds.
True
False
Answers
Answer:
true
Explanation:
Answer:
True
Explanation:
In a displacement reaction, more reactive element displaces less reactive element. Whereas in a double displacement reaction there is exchange of ions of two compounds.
Which of the following is NOT a property of sodium
1. Sodium is a reactive METAL
2. Sodium is very SOFT
3. Sodium is a reactive GAS
4. Sodium forms a WHITE coating
Answers
Answer:
3
Explanation:
Sodium is not a gas, it is a Alkali Metal. I recommend studying the sections of the periodic table to help remember what each element should be.
Hope this helps.
HELP 20 POINTS
What is the frequency of an Electromagnetic wave has with wavelength 2.94 x 10^-8 cm?
Answers
How many grams are in 2.3 x 1024 formula units of KNO3?
Answers
390 g KNO₃
General Formulas and Concepts:ChemistryAtomic Structure
Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.MathPre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right Explanation:Step 1: Define
2.3 × 10²⁴ formula units KNO₃
Step 2: Identify Conversions
Avogadro's Number
Molar Mass of K - 39.10 g/mol
Molar Mass of N - 14.01 g/mol
Molar Mass of O - 16.00 g.mol
Molar Mass of KNO₃ - 39.10 + 14.01 + 3(16.00) = 101.11 g/mol
Step 3: Convert
[tex]2.3 \cdot 10^{24} \ formula \ units \ KNO_3(\frac{1 \ mol \ KNO_3}{6.022 \cdot 10^{23} \ formula \ units \ KNO_3} )(\frac{101.11 \ g \ KNO_3}{1 \ mol \ KNO_3} )[/tex] = 386.172 g KNO₃
Step 4: Check
We are given 2 sig figs. Follow sig fig rules and round.
386.172 g KNO₃ ≈ 390 g KNO₃
Which of the physical processes below result in the formation of metamorphic rocks
Answers
i dont see any processes below
Answer:
Heat and pressure
Explanation:
got it on study island
PLEASE HELP WILL GIVE BRAINLIEST
Answers
Answer:
Coefficients represents no of moles while subscripts represent no of atoms.
Answer:
Coefficients came before formula . Example = 4CO means there are 4 molecules of carbonmonooxide.
Subscripts came after and below the formula . Example = Oxygen gas in which 2 is a subscript which means there are 2 atoms of Oxygen in 1 molecule of Oxygen i.e. oxygen gas
The pressure of a sample of argon gas was increased from 3.89 atm to 8.73 atm at constant temperature. If the final volume of the argon sample was 18.4 L, what was the initial volume of the argon sample? Assume ideal behavior.
Answers
Answer:
41.29 LExplanation:
The initial volume can be found by using the formula for Boyle's law which is
[tex]P_1V_1 = P_2V_2[/tex]
Since we are finding the initial volume
[tex]V_1 = \frac{P_2V_2}{P_1} \\[/tex]
From the question we have
[tex]V_1 = \frac{8.73 \times 18.4}{3.89} = \frac{160.632}{3.89} \\ = 41.293573...[/tex]
We have the final answer as
41.29 LHope this helps you
A radical is a reactive intermediate with a single ____________ electron, formed by ____________ of a covalent bond. Allylic radicals are stabilized by ____________ , making them ____________ stable than tertiary radicals. A compound that contains an especially weak bond that serves as a source of radicals is called a radical ____________ . Treatment of cyclohexene with N-bromosuccinimide in the presence of light leads to ____________ by ____________ intermediates.
Answers
1. A radical is a reactive intermediate with a single ____________ electron, formed by ____________ of a covalent bond.
1. A: Unpaired, and homolysis
2. Allylic radicals are stabilized by ____________ , making them ____________ stable than tertiary radicals.
2. A: Resonance, and more
3. A compound that contains an especially weak bond that serves as a source of radicals is called a radical ____________ .
3. A: Initiator
4. Treatment of cyclohexene with N-bromosuccinimide in the presence of light leads to ____________ by ____________ intermediates.
4. A: Allylic substitution by radical
Which force keeps the planets from floating off into space?
Earth’s gravity
the Sun’s gravity
the moon’s gravity
Milky Way’s gravity
Answers
Answer:
Suns gravity
Explanation:
Answer: 2021
B
The Sun's gravity
Explanation: Just took the big test
Help me as soon as possible I’m gonna dieeee
Answers
the formula of calcium oxide is CaO. What is the formula of the ionic compound containing calium abd sulfate ions
Answers
Answer:
[tex]CaS[/tex]
Explanation:
Hello!
In this case, since calcium's oxidation state when forming ionic bonds is +2 and sulfur's oxidation state when bonding those bonds is -2, for the required formula we write:
[tex]Ca^{2+}S^{2-}[/tex]
Now, since they have the same charge number, we infer the ionic compound formed when they bond is calcium sulfide:
[tex]CaS[/tex]
Best regards!
Will give brainliest