A 175.3 mg sample of C10H12O2 was dissolved in 1.50 g of chloroform (Kb = 3.63 °C/m). What is the boiling point of this solution.
Answer:
[tex]Tb=63.8\°C[/tex]
Explanation:
Hello,
In this case, for the boiling point elevation, we have:
[tex]\Delta T=i*m*Kb[/tex]
Whereas the van't Hoff factor for the given substance is 1 since is not ionizing. Moreover, the molality is computed by:
[tex]m=\frac{mol_{solute}}{m_{solvent}}=\frac{175.3mg*\frac{1g}{1000mg}*\frac{1nol}{164g} }{1.50g*\frac{1kg}{1000g} } =0.713m[/tex]
In such a way, since the boiling point of pure chloroform is 61.2 °C, the boiling point of the solution is:
[tex]Tb=61.2\°C+1*0.713m*3.63\frac{\°C}{m} \\\\Tb=63.8\°C[/tex]
Regards.
Use the periodic table to determine the number of valence electrons in each of the following elements.
Na:
E:
V:
Ar:
Answer:
Na: 1
F: 7
V: 5
Ar: 8
C: 4
Explanation:
The number of valence electrons by using periodic table are Na has 1, F has 7, V has 5, Ar has 8 and C has 4 valence electron.
What is periodic table ?The chemical elements are arranged in rows and columns in the periodic table, sometimes referred to as the periodic table of the elements. It is frequently used in physics, chemistry, and other sciences, and is frequently regarded as a symbol of chemistry.
Because of the orderly arrangement of the elements, it is known as the periodic table. They're arranged in rows and columns, as you'll see. Periods and groups are the names given to the horizontal rows and the vertical columns, respectively.
A system for arranging the chemical elements is the periodic table. The fundamental components of all matter are the chemical elements. The atomic number is a distinct characteristic of each chemical element. This figure is based on how many protons there are in each of the element's atoms.
Thus, The number of valence electrons by using periodic table are Na has 1, F has 7, V has 5, Ar has 8 and C has 4 valence electron.
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In the Lewis structure for ICl2–, how many lone pairs of electrons are around the central iodine atom?
a. 0
b. 1
c. 2
d. 3
e. 4
Answer:
where is rhe structure
A substance formed in a chemical reaction is called a
O A. reactant
B. equation
C. None of these
D. product
Answer: Product
Explanation:
A substance formed in a chemical reaction is called a products ,therefore option (d) is correct .
What do you mean by the chemical reaction ?A chemical reaction is a process that occurs when two or more molecules interact to form a new product(s).
Compounds that interact to produce new compounds are called reactants whereas the newly formed compounds are called products.
Products are substances that are created as a result of a chemical reaction. These products of reactions may be ions or molecules.
The result of a chemical reaction might exist in the solid, liquid, or gaseous phases.
A + B → C + D
Here,
A and B are the reactants, and
C and D are the products of their reaction.
A substance formed in a chemical reaction is called a products ,hence option (d) is correct .
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Barium chloride and sodium sulfate react according to the following equation. BaCl 2 + Na 2SO 4 → BaSO 4 + 2NaCl Answer the following question(s) about this reaction. How many grams of barium chloride are needed to make 100. grams of barium sulfate?
According to the stoichiometry and the given balanced chemical equation 89.22 g of barium chloride are needed to make 100 grams of barium sulfate.
What is stoichiometry?Stoichiometry is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.
Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.
In the given chemical equation, 208.23 g of barium chloride produces 233.38 g of barium sulfate ,so for 100 g of barium sulfate 208.23×100/233.38 =89.22 g of barium chloride is required.
Thus, 89.22 g of barium chloride are needed to make 100 grams of barium sulfate.
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how many moles of MgO are produced when .250 mol of Mg reacts completely with O2
Answer:
0.250 mol
Explanation:
The reaction between Mg and O2 is given by;
2Mg + O2 --> 2MgO
From the equation above; 2 moles of Mg reacts to form 2 moles of MgO.
0.250 mol of Mg would produce x mol of MgO.
2 = 2
0.250 = x
x = 0.250 * 2/2 = 0.250 mol
once energy is applyied to cause a object to vibrate a sound occours
Answer:
its true
Explanation:
Answer:
true
Explanation:
you stop on ground, ground vibrates and makes sound
The umbilicus in on the __ surface of the hand
Answer:
Umbilicus can't be on the hand....it is located in the abdomen....
6. Cross-cuts are best made with which of the following types of knife? A. Utility knife B. Scaler C. Paring knife D. Chef's knife
Answer:
A
Explanation:
Utility knife
Answer:
Utility knife
Explanation:
consider a 1000-ml graduated cylinder with marks every 100 ml. a student records the volume of liquid in the cylinder as 750 ml. is this the correct measurement? explain
Answer:
Explanation:
The 1000-ml graduated cylinder with marks every 100 ml has least count of 100 ml . It means it can not measure a volume less than 100 ml . It can also measure volume in the integral multiple of 100 ml like 200 ml , 300 ml , 400 ml etc perfectly . All these have significant figure of one .
It can not measure volume like 150 , 250 , 255 , 760 etc because these measurements are not the integral multiple of 100 . 750 is not a integral multiple of 100 so it can not measure volume of 750 ml.
Abigail obtained 36.6 grams of calcium carbonate after performing a reaction. From her calculations, she knew she should have obtained 44.1 grams. What was her percent yield
Answer:
it would be 1
Explanation:
Which of the following liquids would have the highest viscosity at room temperature?
1) CH3OCH3
2)CH2Cl2
3) C2H5OH
4) CH3Br
5)HOCH2CH2OH
Answer:
5)HOCH2CH2OH
Explanation:
This is also known as ethylene glycol. An increase in hydrogen bonds of a compound means an increase in the viscosity. Hydrogen bonds occur as a result of bonding with electronegative elements such as Oxygen, Nitrogen etc.
The compounds with the highest amount of Hydrogen bond represents the one with the highest viscosity which is B) HOCH2CH2OH
The liquid which would have the highest viscosity at room temperature is: Choice 5): HOCH2CH2OH.
Discussion:
The compound HOCH2CH2OH, named ethylene glycol relative to the other compounds has more hydrogen bonding.
By convention, an increase in the number of hydrogen bonds of a compound means an increase in the viscosity.
Hydrogen bonds are characterized by the of hydrogen with electronegative elements such as Oxygen, Nitrogen etc.
The compounds with the highest amount of Hydrogen bond is therefore; HOCH2CH2OH.
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How many moles are present 560.0 g of iron (lll) sulfate
Answer:
1.400 mol
Explanation:
To convert grams to moles, you will need the molar mass. The molar mass of iron(iii) sulfate is 399.88 g/mol. Divide grams by the molar mass to find moles.
(560.0 g)/(399.88 g/mol) = 1.400 mol
There are 1.400 mol present in 560.0 g of iron(iii) sulfate.
What is the density if the mass of your object is 54.6g and the volume is 15.30 mL?
Answer:
5ml
Explanation:not sure why
For the reaction of hydrochloric acid and sodium thiosulfate, the rate law is written as:______
A. Rate = k [HCl]m [Na2S2O3]n
B. Rate = k [HCl + Na2S2O3]
C. Rate = t [HCl]a [Na2S2O3]x
D. Rate = t [HCl + Na2S2O3]
Answer:
A. [tex]Rate =k[HCl]^{m} [Na_2S_2O_3]^{n}[/tex]
Explanation:
Let's consider the reaction between hydrochloric acid and sodium thiosulfate.
2 HCl + Na₂S₂O₃ → H₂O + S + SO₂ + 2 NaCl
The rate law is:
[tex]Rate =k[HCl]^{m} [Na_2S_2O_3]^{n}[/tex]
where,
Rate is the reaction ratek is the rate constantm and n are the reaction orders, which can only be determined experimentally and may or not coincide with the stoichiometric coefficients.If 25.0 g of NH₃ and 45.0g of O₂ react in the following reaction, what is the mass in grams of NO that will be formed? 4 NH₃ (g) + 5 O₂ (g) → 4 NO (g) + 6 H₂O (g)
Answer:
The correct answer would be : 33.8 g
Explanation:
Molar mass of ammonia,
Molar Mass = 1* Molar Mass(N) + 3* Molar Mass (H)
= 1*14.01 + 3*1.008 = 17.034 g/mol
mass(NH3)= 25.0 g (given)
number of mol of NH3,
n = mass of NH3/molar mass of NH3
=(25.0 g)/(17.034 g/mol)
= 1.468 mol
Now,
Molar mass of O2
= 32 g/mol
mass(O2)= 45.0 g
similar as ammonia
n (O2)=(45.0 g)/(32 g/mol)
= 1.406 mol
Balanced chemical equation is:
4 NH3 + 5 O2 ---> 4 NO + 6 H2O
1.83456 mol of O2 is required for 1.46765 mol of NH3
by the calculation we have only 1.40625 mol of O2
Thus, the limiting agent will be - O2
now the Molar mass of NO,
= 1*14.01 + 1*16.0
= 30.01 g/mol (similar formula used for NH3)
Balanced equation :
mol of NO formed = (4/5)* moles of O2
= (4/5)×1.40625 (from above calculation)
= 1.125 mol
mass of NO = number of moles × molar mass
= 1.125*30.01
= 33.8 g
Thus, the correct answer would be : 33.8 g
The amount of nitrogen oxide that can be formed in the given mass is 44.12 g.
The given parameters;
mass of ammonia, NH₃ = 25.0 gmass of oxygen, O₂ = 45.0 gThe reaction of the ammonia and oxygen is written as follows;
[tex]4NH_3(g) \ + \ 5O_2 (g) \ --> \ 4NO (g) \ + \ 6H_2O(g)\\\\[/tex]
Molar mass of NH₃ = (14) + (3 x 1) = 17 g/mol
Molar mass of NO = (14) + 16 = 30 g/mol
4(17 g/mol) of NH₃ ------------------ 4(30)
25 g/mol of NH₃ --------------------- ?
[tex]= \frac{4(30) \times 25}{4(17)} \\\\= 44.12 \ g[/tex]
Thus, the amount of nitrogen oxide that can be formed in the given mass is 44.12 g.
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Which factor is least likely to cause a memory problem
Determine whether each of the following salts will form a solution that is acidic, basic, or pH-neutral.
a. KCl
b. NaClO
Answer:
a. Neutral
b. Basic
Explanation:
To determine which of the salts are acidic, neutral or basci we should dissociate them and determine if the ions, can make hydrolysis to water.
KCl → K⁺ + Cl⁻
We need to know, where do the ions come from. In this case, K⁺ comes from the KOH which is a strong base and Cl⁻ comes from the HCl, a strong acid. In conclussion, both are the conjugate weak acid and base, respectively. They do not make hydrolysis, so this salt is neutral. No protons or hydroxides are given.
NaClO → Na⁺ + ClO⁻
The Na⁺ comes from the NaOH, it is the conjugate weak acid from a strong base, while the ClO⁻ comes from the HClO, a weak acid. This means that the ClO⁻ can react to water, to make hydrolysis. The equilibrium will be:
ClO⁻ + H₂O ⇄ HClO + OH⁻
We are giving hydroxides to medium, so the salt is basic.
The SI prefix kilo- indicates _____.
A. hundred
B. thousand
C. hundredth
D. thousandth
Answer:
b
Explanation:
Which of the following pairs of aqueous solutions would not produce a reaction when mixed? Select one: a. NaNO3 and CuCl2 b. Ba(OH)2 and HNO3 c. CaCl2 and Na3PO4 d. AgNO3 and HCl
Answer:
a. NaNO3 and CuCl2
Explanation:
The other 3 react as follows:
Ba(OH)2 and HNO3 ---> BaNO3 + H2O
CaCl2 + Na3PO4 ---> CaPO4 + NaCl
AgNO3 + HCl ---> AgCl + HNO3
Classify the chemical equations as being balanced or not balanced. CaO + 3C → CaC2 + CO Na + H2O → 2NaOH + H2 4Fe + O2 → 2Fe2O3 2Mg + O2 → 2MgO
Answer:
A) Balanced
B) Not Balanced
C) Not Balanced
D) Balanced
A student is using a coffee-cup calorimeter to determine the enthalpy change of the endothermic reaction of two aqueous solutions. After both solutions are added to the cup, the student neglects to put the lid on the cup. This would cause the magnitude of the calculated ΔH° value to be: the answer is: too small, since the solution will absorb heat from the room. But why? Wouldn't depend on if the reaction releases or absorbs heat. Wouldn't it be too large because heat escapes the cup? I'm so confused
Answer:
See the answer below
Explanation:
First, it should be understood that an endothermic reaction is one that absorbs energy in the form of heat from the surrounding. The products of endothermic reactions usually have higher energy than their reactants. Hence, the ΔH° which is referred to as the enthalpy change is usually positive.
Forgetting to cover the coffee-cup calorimeter means some of the heat energy absorbed by the reactants would be exchanged back to the surroundings - a loss. It also means that the enthalpy change would be smaller compared to if the cup had been covered because some of the heat has been lost to the surrounding.
The components that a cell can contain are (check all that apply)
Answer:
The components that a cell can contain are
nucleuscell membraneCytoplasmvacuolecell wallWhich of the following has the greatest electronegativity difference between the bonded atoms?
A) A strong acid made of hydrogen and a halogen, such as HCl
B) A diatomic gas, such as nitrogen (N2)
C) Cartoon bonded to a group 6A (16) nonmetal chalcogen, such as in Co
D) A group 1 alkali metal bonded to chloride, such as RbCl
Answer:
D) A group 1 alkali metal bonded to chloride, such as RbCl
Explanation:
Which of the following has the greatest electronegativity difference between the bonded atoms?
A) A strong acid made of hydrogen and a halogen, such as HCl
The electronegativity difference between H and Cl is:
ΔEN = |EN(H)-EN(Cl)| = |2.1-3.0| = 0.9
B) A diatomic gas, such as nitrogen (N₂)
The electronegativity difference between N and N is:
ΔEN = |EN(N)-EN(N)| = |3.0-3.0| = 0.0
C) Carbon bonded to a Group 6A (16) nonmetal chalcogen, such as in CO
The electronegativity difference between C and O is:
ΔEN = |EN(C)-EN(O)| = |2.5-3.5| = 1.0
D) A group 1 alkali metal bonded to chloride, such as RbCl
The electronegativity difference between Rb and Cl is:
ΔEN = |EN(Rb)-EN(Cl)| = |0.8-3.0| = 2.2
If Na was to form a 2 ion, from what orbital subshell would the second electron be lost?
Answer:
2p
Explanation:
Sodium has an atomic number of 11, thus, the neutral atom has 11 electrons. The electron configuration is:
Na: 1s² 2s² 2p⁶ 3s¹
To gain stability, it loses an electron from its outer shell to form the cation Na⁺. Its electron configuration is:
Na⁺: 1s² 2s² 2p⁶
If it were to lose a second electron to form a Na²⁺ cation, the electron should be lost from the 2p orbital subshell and its electron configuration would be:
Na²⁺: 1s² 2s² 2p⁵
A concentration cell is one in which both the anode and cathode are the same but with different concentrations. Calculate the cell potential with [Zn2+] = 0.10 M[Zn2+] = 0.10 M for the cathode and the [Zn2+] = 0.010 M[Zn2+] = 0.010 M for the anode?
Answer: 0.029 V
Explanation:
For the given chemical reaction :
[tex]Zn^{2+}(0.10M)(aq)+Zn(s)\rightarrow Zn^2+{0.010M)(aq)+Zn(s)[/tex]
Using Nernst equation :
[tex]E_{cell}=E^0_{cell}-\frac{2.303RT}{nF}\log\frac{\text {anodic ion concentration}}{\text {cathodic ion concentration}}[/tex]
where,
F = Faraday constant = 96500 C
R = gas constant = 8.314 J/mol.K
T = room temperature = 298 K
n = number of electrons in oxidation-reduction reaction = 2
[tex]E^0_{cell}[/tex] = standard electrode potential of the cell = 0 (as both metals are same )
[tex]E_{cell}[/tex] = emf of the cell = ?
[tex]E_{cell}=0-\frac{2.303\times 8.314\times 298}{2\times 96500}\log\frac{0.010}{0.10}[/tex]
[tex]E_{cell}=0.029V[/tex]
Thus the cell potential will be 0.029 V
If 801 J of heat is available, what is the mass in grams of iron (specific heat = 0.45 J/g･°C) that can be heated from 22.5°C to 120.0°C?
Answer:
The correct answer will be "18.25 g".
Explanation:
The given values are:
Specific heat,
C = 0.45 J/g･°C
Heat involved,
q = 801 J
Temperature,
ΔT = 120.0°C-22.5°C
= 97.5°C
As we know,
⇒ [tex]C = \frac{q}{m \Delta T}[/tex]
On substituting the given values, we get
⇒ [tex]0.45=\frac{801}{m(97.5)}[/tex]
⇒ [tex]m = 18.25 \ g[/tex]
The mass in grams of iron heated during the change in temperature is 18.26 grams.
Given the following data:
Initial temperature = 22.5°CFinal temperature = 120.0°CQuantity of heat = 801 JoulesSpecific heat capacity of iron = 0.45 J/g°C.To find the mass in grams of iron heated during the change in temperature:
Mathematically, quantity of heat is given by the formula;
[tex]Q = mc\theta[/tex]
Where:
Q represents the heat capacity or quantity of heat. m represents the mass of an object. c represents the specific heat capacity. ∅ represents the change in temperature.Making mass (m) the subject of formula, we have:
[tex]Mass = \frac{Q}{c \theta}[/tex]
Substituting into the formula, we have:
[tex]Mass = \frac{801}{0.45(120\;-\;22.5)} \\\\Mass = \frac{801}{0.45(97.5)} \\\\Mass = \frac{801}{43.875}[/tex]
Mass, m = 18.26 grams.
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Which of these species would you expect to have the highest standard entropy (S°)?
a. CH4(g)
b. C2H2(g)
c. C2H4(g)
d. C2H6(g)
e. C3H8(g)
Answer:
e. C₃H₈(g)
Explanation:
Standard entropy is the absolute entropy of a substance at 1 atm and 25°C.
For different substances in the same phase, molecular complexity determines which ones have higher entropies.
Consider the gases CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₈. Propane (C₃H₈) has a more complex structure and hence more ways to execute molecular motions, which also increase its microstates. Therefore, propane has the greatest standard entropy.
The standard entropy of propane has been highest among the given molecules. Thus, option E is correct.
The standard entropy has been the energy possessed by the 1 mole of a pure substance at standard pressure and temperature.
The entropy has been proportional to the molecular weight and structure complexity. The molecule with higher molecular weight and structure complexity tends to have higher entropy.
In the given set of molecules, the molecular mass and structure complexity of propane has been the highest. Thus, the standard entropy of propane has been highest among the given molecules. Option E is correct.
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Determine whether or not the mixing of each of the two solutions indicated below will result in a buffer.
A. 75.0 mL of 0.10 MHF; 55.0 mL of 0.15 MNaF
B. 150.0 mL of 0.10 MHF; 135.0 mL of 0.175 MHCl
C. 165.0 mL of 0.10 MHF; 135.0 mL of 0.050 MKOH
D. 125.0 mL of 0.15 M CH3NH2; 120.0 mL of 0.25 MCH3NH3Cl
E. 105.0 mL of 0.15 M CH3NH2; 95.0 mL of 0.10 M HCl
A buffer is a solution that mitigates against changes in acidity/alkalinity.
A buffer consists of a weak acid and its conjugate base. Also, a buffer can be formed from a weak base and its conjugate acid. A buffer is a solution that helps to mitigate against changes in acidity and alkalinity.
Let us now examine the solution mixtures listed in the question:
75.0 mL of 0.10 MHF; 55.0 mL of 0.15 MNaF. This can work as a buffer solution because it contains a weak acid (HF) and its conjugate base(F^-).150.0 mL of 0.10 MHF; 135.0 mL of 0.175 MHCl will not function as a buffer solution 165.0 mL of 0.10 MHF; 135.0 mL of 0.050 MKOH will not function as a buffer solution125.0 mL of 0.15 M CH3NH2; 120.0 mL of 0.25 MCH3NH3Cl will not function as a buffer solution105.0 mL of 0.15 M CH3NH2; 95.0 mL of 0.10 M HCl will not function as a buffer solution.Learn more: https://brainly.com/question/13439771
How many atoms are represented by one formula unit of aluminum chromate, Al2(CrO4)3
Answer:
17 atoms
Explanation:
If what we want is to calculate the number of atoms. We must take into account the subscripts of the formula. We can rewrite the formula taking into account the "ones" implicit in the formula, therefore we will have:
[tex]Al_2(Cr_1O_4)_3 [/tex]
Now we have a "3" outside the parenthesis. Therefore, we must multiply this 3 by the number of atoms within the parentheses:
-) Oxygen atoms: 4 x 3 = 12 atoms
-) Chromium atoms: 1 x 3 = 3 atoms.
If we take into account we have 2 aluminum atoms, in total, we will have:
-) 12 oxygen atoms
-) 3 chromium atoms
-) 2 aluminum atoms
12 + 3 + 2 = 17 atoms
In total, we will have 17 atoms.
See figure 1
I hope it helps!