Calculate the pH of a buffer solution prepared by mixing 75.0 mL of 1.25 M lactic acid and 40.0 mL of 0.75 M sodium lactate. (The pKa for lactic acid is 3.86. The molar mass for lactic acid is 90.1 g/mol and the molar mass for sodium lactate is 112.1 g/mol.)
Answer:
pH = 3.37
Explanation:
A weak acid as lactic acid in a solution with sodium lactate (Its conjugate base) produce a buffer. The pH of this buffer is obtained using H-H equation:
pH = pKa + log [A-] / [HA]
Where pH is the pH of the buffer,
pKa is 3.86
And [] could be taken as the moles of A- = Sodium lactate and HA = Lactic acid.
Moles A-:
40.0mL = 0.0400L * (0.75mol / L) = 0.030 moles A-
Moles HA:
75.0mL = 0.0750L * (1.25mol / L) = 0.09375 moles HA
Replacing:
pH = 3.86+ log [0.030 moles A-] / [0.09375 moles HA]
pH = 3.37
PLEASE HELP NEED IT ASAP
A solution has a [H3O+] of 1 × 10−3 M. What is the [OH−] of the solution?
11 M
14 M
1 × 10−14 M
1 × 10−11 M
Answer:
1 × 10−11 M
Explanation:
I took the test :) guy above me is right
Show the complete ionic equation and net ionic equation for all the equations below, then state whether or not a precipitate (insoluble compound) will form. To receive full credit, you must show ALL your work.
Cacl2(aq) + K2co3(aq) + -------->
Bacl2(aq) + MgSO4(aq) + -------->
AgNO3(aq) + Kl(aq) →
Nacl(aq) + (NH4)2Cro4(aq) →
Answer:
(a): Precipitate of calcium carbonate will form.
(b): Precipitate of barium sulfate will form.
(c): Precipitate of silver iodide will form.
(d): Precipitate of sodium chromate will form.
Explanation:
Complete ionic equation is defined as the equation in which all the substances that are strong electrolytes present in an aqueous state and are represented in the form of ions.
Net ionic equation is defined as the equations in which spectator ions are not included.
Spectator ions are the ones that are present equally on the reactant and product sides. They do not participate in the reaction.
(a):
The balanced molecular equation is:
[tex]CaCl_2(aq)+K_2CO_3(aq)\rightarrow 2KCl(aq)+CaCO_3(s)[/tex]
The complete ionic equation follows:
[tex]Ca^{2+}(aq)+2Cl^-(aq)+2K^+(aq)+CO_3^{2-}(aq)\rightarrow 2K^+(aq)+2Cl^-(aq)+CaCO_3(s)[/tex]
As potassium and chloride ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3(s)[/tex]
Precipitate of calcium carbonate will form.
(b)
The balanced molecular equation is:
[tex]BaCl_2(aq)+MgSO_4(aq)\rightarrow MgCl_2(aq)+BaSO_4(s)[/tex]
The complete ionic equation follows:
[tex]Ba^{2+}(aq)+2Cl^-(aq)+Mg^{2+}(aq)+SO_4^{2-}(aq)\rightarrow Mg^{2+}(aq)+2Cl^-(aq)+BaSO_4(s)[/tex]
As magnesium and chloride ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Ba^{2+}(aq)+SO_4^{2-}(aq)\rightarrow BaSO_4(s)[/tex]
Precipitate of barium sulfate will form.
(c):
The balanced molecular equation is:
[tex]AgNO_3(aq)+KI(aq)\rightarrow KNO_3(aq)+AgI(s)[/tex]
The complete ionic equation follows:
[tex]Ag^{+}(aq)+NO_3^-(aq)+K^+(aq)+I^{-}(aq)\rightarrow K^+(aq)+NO_3^-(aq)+AgI(s)[/tex]
As potassium and nitrate ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Ag^{+}(aq)+I^{-}(aq)\rightarrow AgI(s)[/tex]
Precipitate of silver iodide will form.
(d):
The balanced molecular equation is:
[tex]2NaCl(aq)+(NH_4)_2CrO_4(aq)\rightarrow 2NH_4Cl(aq)+Na_2CrO_4(s)[/tex]
The complete ionic equation follows:
[tex]2Na^{+}(aq)+2Cl^-(aq)+2NH_4^+(aq)+CrO_4^{2-}(aq)\rightarrow 2NH_4^+(aq)+2Cl^-(aq)+Na_2CrO_4(s)[/tex]
As ammonium and chloride ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]2Na^{+}(aq)+CrO_4^{2-}(aq)\rightarrow Na_2CrO_4(s)[/tex]
Precipitate of sodium chromate will form.
Element X and Y have the following electronic configurations (X and Y are not the correct symbols of the elements.)
х
Y
2,8,2
2.8.8.2
What is the atomic number of Element Y?
Answer:
20
Explanation:
The atomic number tells you the amount of electrons and protons in an atom so if you add all of the electrons up (2+8+8+2) you get 20.
Hydrochloric acid is widely used as a laboratory reagent in refining ore for the production of tin and tantalum, and as a catalyst in organic reactions. Calculate the number of moles of HCl in 62.85 mL of 0.453 M hydrochloric acid.
Answer: 0.0285 moles of HCl is present in given amount of solution.
Explanation:
Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:
[tex]\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (mL)}}[/tex] .....(1)
Given values:
Molarity of HCl = 0.453 M
Volume of solution = 62.85 mL
Putting values in equation 1, we get:
[tex]0.453mol/L=\frac{\text{Moles of HCl}\times 1000}{62.85}\\\\\text{Moles of HCl}=\frac{0.453\times 62.85}{1000}=0.0285moles[/tex]
Hence, 0.0285 moles of HCl is present in given amount of solution.
What is the law
of universal gravitation?
Answer:
[tex]{ \boxed{ \bf{newtons \: law \: of \: gravitation}}} [/tex]
It states that the product of masses of bodies ( planets and satellites and asteroids ) in space is inversely proportional to square of their separation mean distance
[tex]{ \tt{formular : F = \frac{GMm}{ {r}^{2} } }}[/tex]
To produce a neutral solution, both the anion and the cation of a salt must be neutral.
a. True
b. False
What is AH°f for CO in the following reactions? 2 CO (g) + O2(g) → 2 CO2 (g) AH rxn 564 kJ/mol Given the values of AHF for CO2 is -393 kJ/mol
Explanation:
hi If u don't mind can u plz send a picture as it don't make sense for what is the data given e.g CO
10. A 38.0-g sample of NaOH is dissolved in water, and the solution is diluted to give a final
volume of 1.70 L. The molarity of the final solution is
a. 22.3 M.
b, 0.558 M
c 0.95 M
d. 0.0447 M
e. 0.619 M
Answer:
B.0.558M
Explanation:
M=n/L
n=m/Mm
Mm=NaOH
=23+16+1
=40g/mol
n=m/Mm
= 38/40
=0.95
M=n/L
=0.95/1.70
=0.558
Please help me I need help with this questions I’m very confused fused as to what the answer is please
Which of the following statements is NOT true?
A.) When HX adds to an asymetrical alkene, the SP2 carbon bonded to the most H atoms is protonated.
B.) When HX adds to an asymetrical alkene, protonation leads to the most stable carbocation intermediate.
C.) When HX adds to a symetrical alkene, either of the SP2 carbons can be protonated.
D.) When HX adds to an asymetrical alkene, the halogen attaches to the least substituted SP2 carbon.
Answer:
D.) When HX adds to an asymmetrical alkene, the halogen attaches to the least substituted sp² carbon.
Explanation:
Which of the following statements is NOT true?
A.) When HX adds to an asymmetrical alkene, the sp² carbon bonded to the most H atoms is protonated. TRUE. This is known as Markovnikov's rule.
B.) When HX adds to an asymmetrical alkene, protonation leads to the most stable carbocation intermediate. TRUE. The order of stability of carbocations is tertiary > secondary > primary.
C.) When HX adds to a symmetrical alkene, either of the sp² carbons can be protonated. TRUE. Since the alkene is symmetrical, either carbon can be protonated.
D.) When HX adds to an asymmetrical alkene, the halogen attaches to the least substituted sp² carbon. FALSE. The halogen attaches to the most substituted sp² carbon.
Determine which of these properties would distinguish these two substances: (a) boiling point; (b) combustion analysis results; (c) molecular weight; (d) density at a given temperature and pressure. You can check on the properties of these two compounds
Answer:
(a) boiling point
(d) density at a given temperature and pressure.
Explanation:
Isomers are compounds that have the same molecular formula but different structural formulas. They differ in chemical and physical properties depending on the type of isomerism displayed by the compounds.
The compounds stated here are structural or constitutional isomers hence they possess different boiling points and densities at a given temperature and pressure owing to structural differences in the molecules.
Since they have the same molecular formula, they must yield the same result during combustion analysis and they must have the same molecular weight.
Pb(NO3)2 + 2Naci
2NaNO, + PbCI,
Substance
Number of Protons
Number of
Electrons
2.
3
lithium
fluorine
9
10
19
potassium
sulfur
19
18
16
19. Which substance is electrically neutral?
A. lithium
B. fluorine
Β
C. potassium
D. sulfur
20. Which substance has an overall I'charge?
Answer:
lithium 3
Explanation:
This is because lithium has three protons
A student performs an experiment three times. The results are 4.52 g/mL, 4.54 g/mL, and 4.39 g/mL. Which of the following best describes these results with only the information given in this question?
a. high accuracy
b. high accuracy and high precision
c. high accuracy and low precision
d. high precision
a) When magnesium forms a compound with oxygen, electrons are transferred from the atom to the atom. b) What type of bonding exists between the magnesium and oxygen atoms? c) Indicate the electrical charge on each of the ions and the total electrical charge on the compound.
Answer and Explanation:
Magnesium = Mg (metal) ⇒ oxidation number = +2 (it loses 2 electrons)
Oxygen = O (non-metal) ⇒ oxidation number in oxides = -2 (it gains 2 electrons)
a) We first write the chemical elements with their oxidation numbers in superscripts:
Mg⁺² O⁻²
Then, the oxidation numbers are written crossed as subscripts:
Mg₂O₂
Finally, we divide by a common denominator (2):
MgO
b) Between a metal (Mg) and a non-metal (O), the formed bond is an ionic bond. The metallic element (Mg) loses 2 electrons that are accepted by the non-metallic element (O).
c) Mg : loses 2 electrons ⇒ +2
O: gains 2 electrons ⇒ -2
The total electrical charge is: +2 + (-2) = 0
What is the product of the unbalanced equation below?
Ca(s) + O2(g)
A. CaO2(5)
B. Cao(s)
C. 2Ca(s) + O2(9)
D. Ca20(s)
Answer:
I think B
Explanation:
2Ca + O2 -> 2CaO
The product of the unbalanced equation: [tex]\rm Ca(s) + O_2(g)[/tex] is [tex]\rm CaO(s)[/tex]. The correct answer is option B.
A product is a material which arises from a chemical process. It is the end result of the reaction and is produced by the rearrangement of the atoms or molecules of the reactants.
This reaction's balanced chemical equation is:
[tex]\rm 2Ca(s) + O_2(g) \rightarrow 2CaO(s)[/tex]
The reaction begins by heating calcium metal in the presence of oxygen gas or by exposing calcium metal to oxygen-containing air. Calcium oxide [tex](\rm CaO)[/tex] is formed by the reaction of calcium metal (Ca) with oxygen gas[tex]\rm (O_2)[/tex].
In this equation, two atoms of calcium react with one molecule of oxygen gas to form two molecules of calcium oxide. The reaction is exothermic, meaning it releases heat energy.Therefore, the result of the stated chemical reaction is [tex]\rm CaO(s)[/tex]. Option B is the correct answer.
Learn more about product here:
https://brainly.com/question/32099757
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A sample of a gas has a volume of 1.5L at 150K. If the gas is heated to 235K at constant pressure, what will its final volume be
Answer:
2.35 L
Explanation:
From Charles Law
Applying,
V/T = V'/T'................. Equation 1
Where V = Initial volume of the gas, V' = Final volume of the gas, T = Initial Temperature of the gas, T' = Final temperature of the gas.
Make V' the subject of the equation
V' = VT'/T............... Equation 2
From the question,
Given: V = 1.5 L, T = 150 K, T' = 235 K,
Substitute these values into equation 2
V' = (1.5×235)/150
V' = 2.35 L
Hence the final volume of the gas is 2.35 L
does a negative exponent mean that the number is less than 1
The pressure exerted by a gas container depends on
Which of these do not react with acids. nitrogen, magnesium, zinc,iron
Answer:
Nitrogen gas does not react with acids under normal conditions.
Explanation:
It is 100% correct
Nitrogen does not react with acids, because it is non-metal. Non-metals cannot displace hydrogen from acids.
PLEASE HELP
Let’s say a colleague working in the lab needs to create a solution containing 97.9 grams of NaCl. If she has a 3.0 M stock solution of NaCl dissolved in water, how many liters of the stock solution would she need to have 97.9 grams NaCl? Remember the molar mass of NaCl is 58.44 g/mol.
Answer: There are 0.558 liters of the stock solution would she need to have 97.9 grams NaCl.
Explanation:
Given: Molarity = 3.0 M
Mass of NaCl = 97.9 g
Molar mass of NaCl = 58.44 g/mol
As number of moles is the mass of substance divided by its molar mass.
So, moles of NaCl are calculated as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{97.9 g}{58.44 g/mol}\\= 1.675 mol[/tex]
Molarity is the number of moles of a substance present in liter of a solution.
Therefore, volume of given solution is calculated as follows.
[tex]Molarity = \frac{moles}{Volume (in L)}\\3.0 M = \frac{1.675 mol}{Volume}\\Volume = 0.558 L[/tex]
Thus, we can conclude that there are 0.558 liters of the stock solution would she need to have 97.9 grams NaCl.
Which element has a higher first ionization energy than chlorine (Cl)?
A. Argon (Ar)
B. Phosphorus (P)
C. Lithium (Li)
D. Iodine (I)
Answer:
Argon
Explanation:
It has more electron than chlorine
Sample of 200mls of 0.5 sulphuric acid,was asked to produce 1.2M of the new solution.Calculate the volume of the new solution
Answer: The volume of the new solution is 83.33 mL.
Explanation:
Given: [tex]V_{1}[/tex] = 200 mL, [tex]M_{1}[/tex] = 0.5 M
[tex]V_{2}[/tex] = ?, [tex]M_{2}[/tex] = 1.2 M
Formula used to calculate the volume of new solution is as follows.
[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]
Substitute the values into above formula as follows.
[tex]M_{1}V_{1} = M_{2}V_{2}\\0.5 M \times 200 mL = 1.2 M \times V_{2}\\V_{2} = 83.33 mL[/tex]
Thus, we can conclude that volume of the new solution is 83.33 mL.
3. What do you call the process by which humans extracts stones fron the mountains for
construaction purposes
Find the mass, in grams, of 1.40 x 1023 molecules of Nz. *
Explanation:
hi sorry I wasn't able to find Nz on periodic Table may be just missed it so just find mr of Nz and times it by moles hope this helps
Determine the total kilojoules in two tablespoons of crunchy peanut butter that contains 2 g of carbohydrate, 15 g of fat, and 9 g of protein.
Answer:
The correct answer is -749.437 Kilojoules
Explanation:
In the case of nutrition, Kcal and cal are equal and each macromolecule produces a specific amount of energy in terms of calories. Carbohydrates and protein generate 4 kcal whereas fat generates 9 kcal per gram.
1 g of carbohydrate = 4 kcal
so, 2 gram of carbohydrate = 8 kcal
9 g of protein = 9*4
= 36 kcal
15 g of fat = 15*9
= 135 kcal
in total = 135 + 36 + 8 kcal
= 179 kcal
and, one kcal = 4.186798 kJ
so 179 kcal = 4.186798 * 179
= 749.437 Kilojoules
Two hundred forty-eight milliliters of an acid with an unknown concentration are titrated with a base that has a
concentration of 1.4 M. The indicator changed color when 82 milliliters of base were added. What is the concentration of
the unknown acid?
O 0.46 M
4.2 M
Answer:0.46
Explanation:
What do scientists think life developed from?
simple chemicals
b.
oxygen
a.
c.
photosynthesis
a nucleus
d.
Please select the best answer from the choices provided
A
Answer:
A
Explanation:
Simple chemicals existing at the time synthesized into the earliest life forms into the sea
Answer:
The answer is A!
Explanation:
edg 2022
Metallic bonds form between what kinds of atoms?
Answer: A metallic bond is a type of chemical bond formed between positively charged atoms in which the free electrons are shared among a lattice of cations. In contrast, covalent and ionic bonds form between two discrete atoms. Metallic bonding is the main type of chemical bond that forms between metal atoms.
Explanation:
NOT MY WORDS! I HOPE THIS HELP!!!!!
Answer: Positive charged atom
Explanation: A metallic bond is a type of chemical bond formed between positively charged atoms in which the free electrons are shared among a lattice of cations.
