Answer:
gu kha fuschhehdjdvdbeodbr
90
1
39
is the
In the following decay equation,
90
Sy →
38
et
90
39
-1
A. alpha particle
B. parent element
C. daughter element
D. beta particle
Answer:
D. beta particle
Explanation:
Number of protons increases from 38 to 39 indicating beta decay (only one proton up from parent isotope to daughter isotope) Also atomic mass (on top of an isotope), 90 stays the same as beta particle is very small.
The Lewis dot model of a molecule is shown.
Based on the model, which of the following is true?
Each carbon has three lone pairs of electrons on it.
The octet of carbon atom remains incomplete in the molecule.
The two carbon atoms share a total of six electrons with each other.
The difference between the electronegativity of carbon and hydrogen is greater than 1.7.
Answer:
The two carbon atoms share a total of six electrons with each other.
Explanation:
Looking at the structure of the molecule H-C≡C-H as shown in the question, we will notice that there exists a triple bond between the two carbon atoms.
Each bond between the two carbon atoms represents two electrons shared. Since there are three bonds between the two carbon atoms, then a total of six electrons were shared between the two carbon atoms hence the answer chosen above.
Sodium acetate
NaC2H3O2
SC2H3O2
Na2C2H3O2
Answer:
Sodium acetate is NaC2H3O2
Answer:
The answer is A for the lazy people.
Which of the following compounds would you expect to be an electrolyte?
N2
CH4
H2O
O2
КСІ
Answer:
N2 but i really didn't know
The compound that would be expected to be an electrolyte is : ( A ) N₂
What is an electrolyte
An electrolyte is any subsatnce which conducts electircity when dissolved in a solvent such as water. From the question the compound that can conduct electricty when dissolved in water is N₂
Hence we can conclude that The compound that would be expected to be an electrolyte is : ( A ) N₂
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Based on periodic properties, choose the more metallic element from each of the following pairs.
Match the words in the left column to the appropriate blanks in the sentences on the right.
Between Sr and Sb, the more metallic element is ______
Between \rm Sr and \rm Sb, the more metallic element is _______
Between As and Bi, the more metallic element is ______
Between \rm As and \rm Bi, the more metallic element is _______
Between Cl and O, the more metallic element is ______
Between \rm Cl and \rm O, the more metallic element is ______
Between S and As, the more metallic element is ______
Between \rm S and \rm As, the more metallic element is _______
Answer:
Sr is the more metallic element
Bi is the more metallic element
O is the more metallic element
As is the more metallic element
Explanation:
One thing should be clear; metallic character increases down the group but decreases across the period.
Hence, as we move across the period, elements become less metallic. As we move down the group elements become more metallic.
This is the basis upon which decisions were made about the metallic character of each of the elements listed above.
Tapeworm and Roundworn
Answer:
Tapeworms and roundworms both belong to the same phylum however, their families are different from one another.
Tapeworms are flat, segmented intestinal parasites of the cat and dog and humans sometimes. They are present in the intestines of pets and depend on them, therefore, are parasites. These parasites look like tape which gives it its name.
Roundworms can also infect humans and the most common cases are among children. When not treated immediately, they can cause severe damage to a human host and can even cause blindness. Tapeworms are white in color with a long, segmented body.
The target compound that you should synthesize is 3-chloro-1-butene. Again, this is an electrophilic alkene addition reaction.Examine the product to determine the location of the new functionality. Keep in mind the nature of the intermediate. The regioselectivity is controlled by the stability of this intermediate. Assume that only one equivalent of reagent is used.
Required:
State the starting agents, solvents, and products. What is the main reaction and mechanism? What are the TLC values?
Answer:
Attached below
Explanation:
The starting agents : attached below
There is no Solvent required to carry out this electrophilic alkene addition reaction
The products are : attached below ( Cl )
The TLC values can only be determined by carrying out the experiment in the laboratory ( i.e. it is an experimental observation )
Attached below is the Mechanism showing the starting agents and products
A 0.204 g sample of a CO3 2- antacid is dissolved with 25.0ml of 0.0981 M HCL. The hydrochloric acid that is not neutralized by the antacid is titrated to a bromophenol blue endpoint with 5.83 ml of 0.104 M NaOH. Assuming the active ingredient in the antsacid sample is CaCO3, calculate the mass of CaCO3 in the sample.
Answer:
0.0922 g
Explanation:
Number of moles of acid present = 25/1000 × 0.0981
= 0.00245 moles
Number of moles of base = 5.83/1000 × 0.104
= 0.000606 moles
Since the reaction of HCl and NaOH is 1:1
Number of moles of HCl that reacted with antacid = 0.00245 moles - 0.000606 moles
= 0.001844 moles
From the reaction;
CaCO3 + 2HCl ----> CaCl2 + H2O + CO2
1 mole of CaCO3 reacts with 2 moles of HCl
x moles of CaCO3 reacts with 0.001844 moles ofHCl
x = 1 × 0.001844/2
= 0.000922 moles
Mass of CaCO3 = 0.000922 moles × 100 g/mol
= 0.0922 g
Carbon dioxide gas is collected at 27.0 oC in an evacuated flask with a measured volume of 30.0L. When all the gas has been collected, the pressure in the flask is measured to be 0.480atm. Calculate the mass and number of moles of carbon dioxide gas that were collected.
Answer:
[tex]M_{CO_2}= 25.7g[/tex]
Explanation:
From the question we are told that:
Temperature [tex]T=27.0[/tex]
Volume [tex]V=30L[/tex]
Pressure [tex]P=0.480atm[/tex]
Generally the equation for Ideal gas is mathematically given by
PV=nRT
Therefore
[tex]n=\frac{0.480 x 30}{0.08205 x 300}[/tex]
[tex]n=0.59moles[/tex]
Generally Mass of CO2 is given as
[tex]M_{CO_2}= 0.59 * 44 g/mol[/tex]
[tex]M_{CO_2}= 25.7g[/tex]
Which of the following statements is true about what happens in all chemical reactions? A. The ways in which atoms are joined together is not changed. B. Bonds between atoms are broken and new bonds are formed. C. The final substances are called reactants.
Answer:
B.bonds are broken and new bonds are formed
calculate the pH of 0.01moldm-3 of trioxonitrate (v) acid
Answer:
pH = 2
Explanation:
Trioxonitrate (v) acid is also known as nitric acid (HNO₃) and is one of the strong acid set which when dissolved in water, ionizes 100%. That is,
0.01M HNO₃ => 0.01M H⁺ + 0.01M NO₃⁻ => pH = -log[H⁺] = -log(0.01) = -(-2) = 2
Arrange the following in order of increasing melting point: NaCl, H2O, CH4, C6H4(OH)2.
a. NaCl < H2O < CH4 < C6H4(OH)2
b. CH4 < H2O < NaCl < C6H4(OH)2
c. CH4 < H2O < C6H4(OH)2 < NaCl
d. CH4 < C6H4(OH)2 < H2O < NaCl
e. CH4 < NaCl < C6H4(OH)2 < H2O
Explanation:
one thing to know is that higher surface area = higher boiling point.
NaCl has the smallest surface area, so it's the first one.
H2O has less surface area than methane, so it's second.
Methane has more surface area than H20, so it's third.
The big molecule has the most surface area, so it's last
Temperature measures the average kinetic energy of particles of the substances. Melting point is directly proportional to surface area. Therefore, the correct option is option C.
What is temperature?Temperature is used to measure degree or intensity of heat of a particular substance. Temperature is measured by an instrument called thermometer.
Temperature can be measured in degree Celsius °c, Kelvin k or in Fahrenheit. Temperature is a physical quantity. Heat always flow from higher temperature source to lower temperature source.
We can convert these units of temperature into one another. The relationship between degree Celsius and Fahrenheit can be expressed as:
°C={5(°F-32)}÷9
Melting point is directly proportional to surface area. NaCl has the smallest surface area. Water has less surface area than methane. Methane has more surface area than H[tex]_2[/tex]O.
Therefore, the correct option is option C.
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Write chemical equations for the reactions that occur when solutions of the following substances are mixed:
a. HNO₂ (nitrous acid) and C₂H₇NO (aq) ethanolamine, a base.
b. H₃O+ and F-
a) HNO₂ + C₂H₇NO → N₂ + C₂H₆O + H₂O
b) H₃O⁺ + F⁻ → HF + H₂O
[tex]\large\color{lime}\boxed{\colorbox{black}{Answer : - }}[/tex]
a) HNO₂ + C₂H₇NO → N₂ + C₂H₆O + H₂O
b) H₃O⁺ + F⁻ → HF + H₂O
What is the pressure in a 19.1 L cylinder filled with 0.684 mol of nitrogen gas at a temperature of 326 K ?
Answer:
The hydrogen sample has a pressure of 0.957 atmospheres.
Explanation:
Let consider that the hydrogen sample behaves ideally, the equation of state for ideal gases is:
[tex]P\cdot V = n\cdot R_{u}\cdot T[/tex] (1)
Where:
[tex]P[/tex] - Pressure, in atmospheres.
[tex]V[/tex] - Volume, in liters.
[tex]n[/tex] - Molar quantity, in moles.
[tex]T[/tex] - Temperature, in Kelvin.
[tex]R_{u}[/tex] - Ideal gas constant, in atmosphere-liters per mole-Kelvin.
If we know that [tex]V = 19.1\,L[/tex], [tex]n = 0.684\,mol[/tex], [tex]T = 326\,K[/tex] and [tex]R_{u} = 0.082\,\frac{atm\cdot L}{mol\cdot K}[/tex], then the pressure of the hydrogen sample is:
[tex]P = \frac{n\cdot R_{u}\cdot T}{V}[/tex]
[tex]P = \frac{(0.684\,mol)\cdot \left(0.082\,\frac{atm\cdot L}{mol\cdot K} \right)\cdot (326\,K)}{19.1\,L}[/tex]
[tex]P = 0.957\,atm[/tex]
The hydrogen sample has a pressure of 0.957 atmospheres.
Protons,neutrons and electrons are not considered as------------ *
Electrons are a type of subatomic particle with a negative charge. Protons are a type of subatomic particle with a positive charge. ... Neutrons are a type of subatomic particle with no charge (they are neutral). Like protons, neutrons are bound into the atom's nucleus as a result of the strong nuclear force.
2. XC12 is the chloride of metal X. The formulae of its sulphate is
Answer:
XSO₄
Explanation:
XCl₂ is the chloride of metal X. The sum of the charges of the cation and the anion must be zero because the salt is electrically neutral. The charge of the cation of X is:
1 × X + 2 × Cl = 0
1 × X + 2 × (-1) = 0
X = +2
X has a charge +2 and sulphate (SO₄²⁻) a charge -2. The neutral salt they form is XSO₄.
Convert 1.25 x 1024 atoms of carbon to moles of carbon.
Answer:
2.076
Explanation:
1 mole is 6.02 * 10^23
To convert from atoms (or molecules or compounds or ions etc.) to mols, you divide the number of atoms (or molecules or etc.) by 6.02 * 10^23
So it is (1.25 * 10^24)/(6.02 * 10^23)
=2.076
Answer:
[tex]\boxed {\boxed {\sf 2.08 \ mol \ C}}[/tex]
Explanation:
We are asked to convert a number of carbon atoms to moles.
We will use Avogadro's Number for this, which is 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. For this problem, the particles are atoms of carbon. There are 6.022 ×10²³ atoms of carbon in 1 mole of carbon.
We will also use dimensional analysis to solve this problem. To do this, we use ratios. Set up a ratio using the underlined information.
[tex]\frac {6.022 \times 10^{23} \ atoms \ C}{1 \ mol \ C}[/tex]
We are converting 1.25 ×10²⁴ atoms of carbon to moles, so we multiply the ratio by that value.
[tex]1.25 \times 10^{24} \ atoms \ C* \frac {6.022 \times 10^{23} \ atoms \ C}{1 \ mol \ C}[/tex]
Flip the ratio. It remains equivalent, but it allows us to cancel the units atoms of carbon.
[tex]1.25 \times 10^{24} \ atoms \ C* \frac{1 \ mol \ C} {6.022 \times 10^{23} \ atoms \ C}[/tex]
[tex]1.25 \times 10^{24} * \frac{1 \ mol \ C} {6.022 \times 10^{23} }[/tex]
[tex]\frac{1.25 \times 10^{24} } {6.022 \times 10^{23} } \ mol \ C[/tex]
[tex]2.075722351 \ mol \ C[/tex]
The original measurement of atoms has three significant figures, so our answer must have the same. For the number we calculated, that is the hundredths place. The 5 in the thousandths place tells us to round the 7 up to an 8.
[tex]2.08 \ mol \ C[/tex]
1.25 ×10²⁴ atoms of carbon is equal to approximately 2.08 moles of carbon.
One crystalline form of silica (SiO2) has a cubic unit cell, and from X-ray diffraction data it is known that the cell edge length is 0.700 nm. If the measured density is 2.32 g/cm3, how many (a) Si4 and (b) O2- ions are there per unit cell
Answer:
There are 8Si atoms and 16 O atoms per unit cell
Explanation:
From the question we are told that:
Edge length [tex]l=0.700nm=>0.7*10^9nm[/tex]
Density [tex]\rho=2.32g/cm^3[/tex]
Generally the equation for Volume is mathematically given by
[tex]V=l^3[/tex]
[tex]V=(0.7*10^9)m^3[/tex]
[tex]V=3,43*10^-{22}cm[/tex]
Where
Molar mass of (SiO2) for one formula unit
[tex]M=28+32[/tex]
[tex]M=60g/mol[/tex]
Therefore
Density of Si per unit length is
[tex]\rho_{si}=\frac{9.96*10^{23}}{3.43*10^22}[/tex]
[tex]\rho=0.29[/tex]
Molar mass of (SiO2) for one formula unit
[tex]M=28+32[/tex]
[tex]M=60g/mol[/tex]
Therefore
There are 8Si atoms and 16 O atoms per unit cell
Identify the element for each of these electron configurations. Then determine whether this configuration is the ground state or an excited state.
a. 1s2 2s2 2p6 3s2 3p6 4s2 3d 9
b. 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f 14 5d7
Answer:
a. 1s2 2s2 2p6 3s2 3p6 4s2 3d 9 - the element is zinc and this is an excited state configuration
b. 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f 14 5d7 -the element is iridium and this is a ground state configuration
Explanation:
The ground state is the lowest energy state of an atom while excite states of Zn atom are higher energy states.
The configuration, 1s2 2s2 2p6 3s2 3p6 4s2 3d 9 applies to zinc atom in excited state while the configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f 14 5d7 applies to iridium atom in ground state.
8) Determine whether mixing each pair of the following results in a buffera. 100.0 mL of 0.10 M NH3 with 100.0 mL of 0.15 MNH4Cl b. 50.0 mL of 0.10 M HCL with 35.0 mL of 0.150 M NaOHc. 50.0 mL of 0.15 M HF with 20.0 mL of 0.15 M NaOHd. 175.0 mL of 0.10 M NH3 with 150.0 mL of 0.12 M NaOH
Answer:
a. 100.0 mL of 0.10 M NH₃ with 100.0 mL of 0.15 M NH₄Cl.
c. 50.0 mL of 0.15 M HF with 20.0 mL of 0.15 M NaOH.
Explanation:
A buffer system is formed in 1 of 2 ways:
A weak acid and its conjugate base.A weak base and its conjugate acid.Determine whether mixing each pair of the following results in a buffer.
a. 100.0 mL of 0.10 M NH₃ with 100.0 mL of 0.15 M NH₄Cl.
YES. NH₃ is a weak base and NH₄⁺ (from NH₄Cl ) is its conjugate base.
b. 50.0 mL of 0.10 M HCl with 35.0 mL of 0.150 M NaOH.
NO. HCl is a strong acid and NaOH is a strong base.
c. 50.0 mL of 0.15 M HF with 20.0 mL of 0.15 M NaOH.
YES. HF is a weak acid and it reacts with NaOH to form NaF, which contains F⁻ (its conjugate base).
d. 175.0 mL of 0.10 M NH₃ with 150.0 mL of 0.12 M NaOH.
NO. Both are bases.
Analyze the transition of a photon
Calculate the percent error in the atomic weight if the mass of a Cu electrode increased by 0.4391 g and 6.238x10-3 moles of Cu was produced. Select the response with the correct Significant figures. You may assume the molar mass of elemental copper is 63.546 g/mol. Refer to Appendix D as a guide for this calculation.
Answer:
10.77%
Explanation:
Molar mass of Cu = mass deposited/number of moles of Cu
Molar mass of Cu = 0.4391 g/6.238x10^-3 moles
Molar mass of Cu = 70.391 g/mol
%error = 70.391 g/mol - 63.546 g/mol/63.546 g/mol × 100
%error = 10.77%
Calculate the numerical value of the equilibrium constant, Kc, for the reaction below if the equilibrium concentrations for CO, H2 , CH4 and H2O are 0.989 M, 0.993 M, 1.078 M and 0.878 M, respectively. (calculate your answer to three sig figs)
CO(g) + 3 H2(g) ⇌ CH4(g) + H2O(g)
Kc = [CH4]×[H2O] / [CO]×[H2]^3
Kc = 1.078×0.878 / (0.989×0.933^3)
Kc = 0.977
The numerical value of the equilibrium constant, Kc, for the given reaction is found to be 0.977.
What is Equilibrium constant?The Equilibrium constant may be defined as the numerical value that significantly indicated the correlation between the amounts of products and reactants present at equilibrium in a reversible chemical reaction at a definite temperature.
According to the question, the reaction is as follows:
[tex]CO +3H_2[/tex] ↔ [tex]CH_4+ H_2O[/tex].
The equilibrium concentrations are 0.989 M, 0.993 M, 1.078 M and 0.878 M, respectively.
Now, the equilibrium constant is calculated by the following formula:
Kc = [CH4]×[H2O] / [CO]×[tex][H_2]^3[/tex]= 1.078×0.878 / (0.989×0.93[tex]3^3[/tex]).
= 0.9464/(0.989 × 0.8121)
= 0.977.
Therefore, the numerical value of the equilibrium constant, Kc, for the given reaction is found to be 0.977.
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What is the pH of a solution with an [H+] of (a) 5.4 x 10-10, (b) 4.3 x 10-5, (c) 5.4 x 10-7?
Answer:
a. 9.2
b. 4.4
c. 6.3
Explanation:
In order to calculate the pH of each solution, we will use the definition of pH.
pH = -log [H⁺]
(a) [H⁺] = 5.4 × 10⁻¹⁰ M
pH = -log [H⁺] = -log 5.4 × 10⁻¹⁰ = 9.2
Since pH > 7, the solution is basic.
(b) [H⁺] = 4.3 × 10⁻⁵ M
pH = -log [H⁺] = -log 4.3 × 10⁻⁵ = 4.4
Since pH < 7, the solution is acid.
(c) [H⁺] = 5.4 × 10⁻⁷ M
pH = -log [H⁺] = -log 5.4 × 10⁻⁷ = 6.3
Since pH < 7, the solution is acid.
Balance the redox reaction Al(s) + MnO4^- (aq) --> MnO2 (s) + Al(OH)4^- (aq) in aqueous basic solution
Answer:
Al + MnO4- + 2H2O → Al(OH)4- + MnO2
Explanation:
First of all, we out down the skeleton equation;
Al + MnO4- → MnO2 + Al(OH)4-
Secondly, we write the oxidation and reduction equation in basic medium;
Oxidation half equation:Al + 4H2O + 4OH- → Al(OH)4- + 4H2O + 3e-
Reduction half equation:MnO4- + 4H2O + 3e- → MnO2 + 2H2O + 4OH-
Thirdly, we add the two half reactions together to obtain:
Al + MnO4- + 8H2O + 4OH- + 3e- → Al(OH)4- + MnO2 + 6H2O + 3e- + 4OH-
Lastly, cancel out species that occur on both sides of the reaction equation;
Al + MnO4- + 8H2O→ Al(OH)4- + MnO2 + 6H2O
The simplified equation now becomes;
Al + MnO4- + 2H2O → Al(OH)4- + MnO2
Select the structure of a compound C6H14 with a base peak at m/z 43.
A) CH3CH2CH2CH2CH2CH3
B) (CH3CH2)2CHCH3
C) (CH3)3CCH2CH3
D) (CH3)2CHCH(CH3)2
E) None of these choices.
The structure of a compound C₆H₁₄ with a base peak at m/z 43 is none of these .
What is a compound?Compound is defined as a chemical substance made up of identical molecules containing atoms from more than one type of chemical element.
Molecule consisting atoms of only one element is not called compound.It is transformed into new substances during chemical reactions. There are four major types of compounds depending on chemical bonding present in them.They are:
1)Molecular compounds where in atoms are joined by covalent bonds.
2) ionic compounds where atoms are joined by ionic bond.
3)Inter-metallic compounds where atoms are held by metallic bonds
4) co-ordination complexes where atoms are held by co-ordinate bonds.
They have a unique chemical structure held together by chemical bonds Compounds have different properties as those of elements because when a compound is formed the properties of the substance are totally altered.
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For the following reaction, 4.77 grams of carbon (graphite) are allowed to react with 16.4 grams of oxygen gas.
carbon (graphite) (s) + oxygen (g) → carbon dioxide (g)
1. What is the maximum amount of carbon dioxide that can be formed?
2. What is the FORMULA for the limiting reagent?
3. What mass of the excess reagent remains after the reaction is complete?
Answer:
1. 17.5 g of CO₂
2. The limiting reactant is carbon (graphite), and its formula is C(graphite)
3. 3.7 g of O₂
Explanation:
First, we have to write the chemical equation for the reaction. For this, we have to know the chemical formula of each reactant and product:
Reactants: carbon(graphite) ⇒ C(graphite) ; oxygen gas ⇒ O₂(g)Products: carbon dioxide ⇒ CO₂(g)Thus, we write the chemical equation:
C(graphite) + O₂(g) → CO₂(g)
The equation is already balanced because it has the same number of C and O atoms on both sides. Thus, we can see that 1 mol of C(graphite) reacts with 1 mol of O₂ and produce 1 mol of CO₂ (mole-to-mole reaction).
Now we convert the grams of reactants to moles by using the molecular weight (Mw) of each compound:
Mw(C) = 12 g/mol
moles of C(graphite) = 4.77g/(12 g/mol) = 0.3975 mol
Mw(O₂) = 16 g/mol x 2 = 32 g/mol
moles of O₂ = 16.4 g/(32 g/mol) = 0.5125 mol
Now, we can compare the stoichiometric ratio (given by the moles of reactants in the equation) with the actual ratio (given by the mass of reactants we have):
stoichiometric ratio ⇒ 1 mol C(graphite)/mol O₂
actual ratio ⇒ 0.3975 mol C(graphite)/0.5125 mol O₂
We can see that we need 0.3975 moles of O₂ to react with C(graphite) and we have more moles (0.5125 mol) so the excess reactant is O₂. Thus, the limiting reactant is C(graphite).
The amount of product (CO₂) that is formed is calculated from the amount of limiting reactant. We can see in the chemical equation that 1 mol of CO₂ is produced from 1 mol of C(graphite) ⇒ stoichiometric ratio = 1 mol CO₂/mol C(graphite).
Thus, we multiply the moles of C(graphite) we have by the stoichiometric ratio to calculate the moles of CO₂ produced:
moles of CO₂ = 0.3975 mol C(graphite) x 1 mol CO₂/mol C(graphite) = 0.3975 mol CO₂
Now, we convert the moles of CO₂ to mass by using the Mw:
Mw(CO₂) = 12 g/mol + (16 g/mol x 2) = 44 g/mol
mass of CO₂ = 0.3975 mol CO₂ x 44 g/mol CO₂ = 17.5 g
Therefore, the maximum amount of carbon dioxide (CO₂) formed is 17.5 g.
Since this is a mole-to-mole reaction, the moles of excess reactant that remains after the reaction is complete is calculated as the difference between the moles of excess reactant and limiting reactant:
remaining moles of O₂ = 0.5125 mol - 0.3975 mol = 0.115 mol O₂
Finally, we convert the moles of O₂ to mass with the Mw (32 g/mol) :
mass of O₂ = 0.115 mol O₂ x 32 g/mol = 3.68 g
Therefore, the mass of the excess reagent that remains after the reaction is complete is 3.7 g.
Suppose you are studying the Ksp of CaCl2, which has a molar mass of 110.98 g/mol, at multiple temperatures. You dissolve 4.99 g of CaCl2 in 10.0 mL of water at 100 oC and cool the solution. At 90 oC, a solid begins to appear. What is the Ksp of CaCl2 at 90 oC
Answer:
Hence the Solubility product,
Ksp = [Ca2+] [Cl-]2
or, Ksp = (4.5) (9)2
or, Ksp = 364.5
Explanation:
Mass of CaCl2 = 4.99 g
Molar mass of CaCl2 = 110.98 g/mol
Moles of CaCl2
= given mass/ molar mass
= 4.99/ 110.98
= 0.045
Volume = 10.0 mL = 0.01 L
CaCl2 dissociates into its ion as:
CaCl2 (s) \rightleftharpoons Ca2+ (aq) + 2 Cl- (aq)
At 90°C, the solution is saturated with Ca2+ and Cl- ions.
Moles of Ca2+ = Moles of CaCl2 dissolved = 0.045
Moles of Cl- = 2 x ( Moles of CaCl2 dissolved) = 2 x 0.045 = 0.09
[Ca2+] = Moles/ Volume = 0.045/ 0.01 = 4.5 M
[Cl-] = 0.09/ 0.01 = 9 M
Solubility product,
Ksp = [Ca2+] [Cl-]2
or, Ksp = (4.5) (9)2
or, Ksp = 364.5
Calculate the vapor pressure of a solution made by dissolving 550 grams of glucose (molar mass = 180.2 g/mol) in 1020.0 ml of water at 25°C. The vapor pressure of pure water at 25°C is 23.76 mm Hg. Assume the density of the solution is 1.00 g/ml. (760 torr = 760 mmHg = 1 atm)
Answer:
22.55 mmHg (0.03 atm)
Explanation:
According to Raoult's law, the vapor pressure (Psolution) of a solution is given by:
Psolution = Xsolvent x Psolvent
Where Xsolvent is the mole fraction of the solvent in the solution and Psolvent is the vapor pressure of the pure solvent.
From the data, we have: Psolvent = 25.76 mmHg
We have to calculate Xsolvent, which is equal to the moles of solvent divided into the total number of moles.
The solution is composed of the solute (glucose) dissolved in the solvent (water). So, the total number of moles is calculated from the moles of solute and solvent.
To calculate the moles of solute (glucose), we divide the mass of glucose into its molar mass:
moles of glucose = mass/molar mass = 550 g/(180.2 g/mol) = 3.05 mol
The same for the moles of solvent (water). The mass of water is obtained from the product of the volume and density:
mass of water = volume x density = 1020.0 mL x 1.00 g/mL = 1020.0 g
molar mass H₂O = (1 g/mol x 2) + 16 g/mol = 18 g/mol
moles of water = mass water/molar masss = 1020.0 g/(18 g/mol) = 56.67 mol
Now, we can calculate Xsolvent:
Xsolvent = moles of water/total moles
total moles = moles glucose + moles water = 3.05 mol + 56.67 mol = 59.72 mol
⇒ Xsolvent = 56.67 mol/(59.72 mol) = 0.9489
Finally, we calculate the vapor pressure of the solution:
Psolution = 0.9489 x 23.76 mmHg = 22.55 mmHg
22.55 mmHg x 1 atm/760 mmHg = 0.03 atm
Why does nitrogen not show allotropy?
Answer:
Nitrogen does not show allotropy because of its small size and high electronegativity. The single N-N bond is weaker than P-P bond because of high inter electronic repulsions among non-bonding electrons due to the small bond distance. Hence it does not show allotropy.
Answer:
The nitrogen atom has short inter-bond distance, hence highly electronegative in terms of magnitude. This creates no relation in energy varieties hence no allotropes formed.
Nitrogen atom is also very small.
