The volume at which the pH can be used to determine the pKa of the acid is 7.40 ml if the equivalence point occurred at 14.81 ml of added sodium hydroxide.
The weak acid and the conjugate base will have an equal number of moles at the half-equivalence point as the number of moles of sodium hydroxide will neutralize half of the number of moles of the weak acid which will then produce more conjugate base.
The chemical reaction can be given as;
HA = (H^+) + A^-
Calculation of pKa:
pH = pKa + log[A^-]/[HA]
At half equivalence point, pH = pKa
As, ka = 10^-pka
Therefore, ka = 10^-pH
Volume is given which is 14.81 ml. Therefore, the volume that is used to determine the pKa of the acid can be calculated as follows;
14.81/2 = 7.40 ml
Therefore the volume used to determine the pKa of the acid is calculated to be 7.40 ml
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which is the correct answer
Answer C I think
Explanation:
which statement about matter is true? responses matter is anything that is made of atoms and that has mass. matter is anything that is made of atoms and that has mass. matter is a compound. matter is a compound. matter is anything that is made of organic substances and is found on the earth. matter is anything that is made of organic substances and is found on the earth. matter is an element.
The true statement about Matter is that matter is anything that is made up of atoms and that has mass.
Matter is anything which is made up of mass and that has mass. and that occupies space.
If we talk about space, there is no matter because there is nothing but vacuum.
Matter is a general terms given to a group of atoms or molecules which are taken in a general.
We all are made up of atoms, because we al have mass and we all occupy some space. The same goes to anything that we can see or touch or feel that it exist.
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Answer: Matter is anything that is made of atoms and that has mass.
Explanation: I took the test.
calculate the volume of concentrated nitric acid (16 m) required to react with 0.41 g of cu(s) if you use 1.86 ml (an excess) of hno3, what volume of 5.0m naoh will you need to neutralize the solution after the copper is completely dissolved?
The volume of Concentrated nitric acid (16 m) required to react with 0.41 g of cu(s) if you use 1.86 ml (an excess) of hno3, what volume of 5.0m naoh will need to neutralize completely dissolved is 0.704 ml
4 HNO3(l) + Cu(s) ==> Cu(NO3)2(s and aq) + 2 NO2(g) + 2 H2O(l)
According to net Ionic equation 4 moles of HNO3 reacts with 1 mole of Cu(s)
moles of Cu in 0.36 gm of Cu = 0.36/63.5
moles = molarity*volume(L)
moles of Cu*4 =moles of HNO3
Let volume of HNO3 be x
0.36/63.5*4 = 16*x
x = 1.42 ml
c. Volume of HNO3 added = 1.64 ml
excess of HNO3 = 1.64-1.42
= 0.22 ml
Normality of NaOH and HNO3 is same i.e. equal moles of NaOH and HNO3 neutralises itself
molarity of NaOH = 5 moles/litre
moles of NaOH = Moles Of HNO3
5*x = 16*0.22
x = 0.704 ml
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The strong attractive forces in ionic crystals make them ______, ______, and ______ solids. Group of answer choices rigid, hard, and brittle rigid, clear, and electronegative homogeneous, brittle, and ionic hard, electronegative, and homogeneous
The strong attractive forces in ionic crystal make them rigid , hard and brittle solid.
Ionic crystal are so strong because of the strong attractive forces between ions . Ionic compound formed between a positively charged ion and a negatively charged ion , the bond between them are so strong that make ionic crystal brittle. and also make it rigid. the presence of strong electrostatic force of attraction make the ionic crystal so hard. Due to the non directional nature of ionic bond make the crystal brittle.
Thus, The strong attractive forces in ionic crystal make them rigid , hard and brittle solid.
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what is stripped from each water molecule
Answer:
HS is stripped from each O.
what is periodic table
Answer:
the periodic table is the table of contents of the elements
When you put aspirated spinach leaf disks in a beaker of sodium bicarbonate and place them in different colors of light, some disks float faster & more abundantly than others dependent on what color, if any, they were in. What made them able to float?.
The release of O₂( oxygen) from the process of photosynthesis is what made them to be able to float.
What is Photosynthesis?This is referred to as the process in which green plants manufacture their food in the presence of sunlight which is trapped by chlorophyll.They are known as primary producers and they use compounds such as water and carbondioxide.
The reactants mentioned above undergo series of reactions which leads to the production of glucose and oxygen is given off as a result which is the element responsible for the floating of the aspirated spinach leaf disks in this scenario.
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a factory has a batch of hand sanitizer with 50\pp, percent alcohol content. how much pure (100\00, percent concentration) alcohol should they include in a 600\,\text{ml}600 ml 600, start text, m, l, end text bottle to make a 68\hh, percent mixture?
Using the percentage by volume of the solutions given, we can calculate that we require 216 mL of 100% alcohol and 384 mL of 50% alcohol.
The percentages given refer to the percentage by volume (%V). We need to make 600 mL of 68% alcohol solution, by mixing a certain volume of 50% solution (A) and a certain volume of 100% alcohol (B). So, we know that:
A + B = 600 mL
We also know that the total volume of alcohol in the end solution needs to be:
0.68 * 600 mL = 408 mL
So, by extension:
0.50 * A + B = 408 mL
Based on the first equation, we can say that:
A = 600 mL - B
If we use that A in the second equation we get:
0.50 * (600 mL - B) + B = 408 mL
300 mL - 0.50 B + B = 408 mL
If we rearrange this equation we get:
B - 0.50 * B = 408 mL - 300 mL
0.50 * B = 108 mL
B = 108 mL / 0.50
B = 216 mL
A = 600 mL - 216 mL = 384 mL
So, we need 216 mL of 100% alcohol and 384 mL of 50% alcohol solution to get 600 mL of 68% alcohol solution.
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Answer:216 ml
Explanation: I got it right
1. a. What is work? Write its SI unit and the factors affecting work
Elements that readily gain electrons tend to have a
a) high ionization energy and low electronegativity
b) low ionization energy and low electronegativity
c) high ionization energy and high electronegativity
d)l ow ionization energy and high electronegativity
Answer:
C. high ionization energy and high electronegativity
Explanation:
When an electron is gained or lost from an atom or a molecule, an ion is formed. When a molecule or atom gains electrons, anions (which are negatively charged ions) are formed.
can someone help me please?
What pressure will be required for neon at 30°C to have the same density as nitrogen at 20°C and 1.0 atm?
1.5 atm pressure will be required for neon at 30°C to have the same density as nitrogen at 20°C and 1.0 atm.
What is the theory of the ideal gas law?The relationship between a gas's pressure P, volume V, and temperature T in the range of low pressures and high temperatures, when the gas's molecules move virtually independently of one another, is known as the ideal gas law, also known as the perfect gas law.
Briefing:T[tex]_N_e[/tex] =30⁰C=(30+273)K=303K
T[tex]_N_2[/tex] =20⁰C=(20+273)K=293K
P[tex]_N_2[/tex] =1.0atm
Ideal gas constant - R=0.0821L⋅atm/ K⋅ mol
The molar mass of
Neon - M[tex]_N_e[/tex]=20.18g/mol
Nitrogen - M[tex]_N_2[/tex] =2⋅14.007g/mol=28.014g/mol
Determine the pressure P[tex]_N_e[/tex] required for neon at 30⁰C to have the same density (d) as nitrogen at 20⁰C.
d = m/V
We know that
n = m/M
Using the ideal gas law, we get
PV = nRT
PV = m/M *RT
Since
PM/RT = m/V =d
d = PM/RT
d= [tex]\frac{P_{N_2} M_{N_2}}{R T_{N_2}}[/tex]
d = 1.0 atm * 28.014 g/mol/0.0821L atm/K mol 293K
d = 1.2 g//L
Since both gases have the same density, we can calculate the pressure of neon gas, using
[tex]d=\frac{P_{N e} M_{N e}}{R T_{N e}}[/tex]
[tex]P_{N e}=\frac{d R T_{N e}}{M_{N e}}[/tex]
[tex]P_{N e}[/tex]=1.2g/L . 0.0821L . atm/K.mol.303 K/20.18 g/mol
[tex]P_{N e}[/tex]=1.5 atm
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How many moles are in 2.931g of sulfur?
a mineral compound is composed of mn and o. if 77% of the mass of the mineral compound is due to manganese, what is the empirical formula of the mineral compound?
Answer:
MnO
Explanation:
See the attachwed worksheet
3.23x106 kJ to kcal
Express the value kilocalories in to three significant figures
help me please!
The value into kilocalories up to three significant figures is 77.1 x 10^3 kilocalories
1 kj = 0.239 kilocalorie
3.23 x 10^6 kJ x 0.239 kilocalorie = 77.1 x 10^3 kilocalories
3.23 x 10^6 kJ = 77.1 x 10^3 kilocalories
What is Significant figure ?In chemistry, Significant figures are the digits of value which carry meaning towards the resolution of the measurement. They are also called significant figures in chemistry. All the experimental measurements have some kind of uncertainty associated with them.
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A student mixes 5.0 g of a sodium bicarbonate solution with 6.0 g of a potassium aluminum sulfate solution in a sealed container. A white, solid precipitate is formed. What is the total mass after the reaction has taken place?More than 11.0 gLess than 11.0 g11.0 gNot enough information
First, we have to remember the law of conservation of matter:
"The matter can not be created nor destroyed. It can only be transformed".
Then, the answer, in theory, has to be 11.0 g, that is the addition of 5.0 g and 6.0 g.
Which list consists of elements that have the most similar chemical properties?
a) Cu, Zn, Fe
b) K, Ca, Br
c) Mg, Al, Si
d) Cs, Na, K
The list that consists of elements that have the most similar chemical properties is caesium, sodium and potassium (option D).
What is the periodic table?Periodic table is the tabular chart of the chemical elements according to their atomic numbers so that elements with similar properties are in the same group (column).
The periodic table is made up of chemical elements arranged in groups and periods. Chemical elements in the same group possess similar chemical properties.
According to this question, the following elements are in the same group 1:
Caesium is a chemical element (symbol Cs) with an atomic number of 55. It is a soft, gold-colored, highly reactive alkali metal. Sodium is a chemical element (symbol Na) with an atomic number of 11 and atomic weight of 22.98977.Pottasium is an element (symbol K) with an atomic number of 19 and atomic weight of 39.0983.Therefore, Cs, K and Na will have the most similar chemical properties because they belong to the same group.
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Use the chemical equation to complete the activity. 4Fe + 3O2 → 2Fe2O3 Iron (Fe) reacts with oxygen (O2) to form iron oxide. A scientist adds 15.4 grams of Fe to 3.6 grams of O2 to start the reaction. All of the iron and oxygen react to form iron oxide. Explain in detail how you can determine how many grams of iron oxide will be produced.
The mass of the iron oxide produced in the given chemical reaction is equal to 27.04 grams.
What is the limiting reagent?The limiting reagent in a chemical reaction can be described as that reactant that will decide the amount of the yield of the product. The reactant consumed first will confirm the completion of the reaction if the reactants are not taken in stoichiometry.
Given the chemical reaction of the formation of iron oxide:
4Fe + 3O₂ → 2Fe₂O₃
Given the mass of the iron = 15.4 grams
The moles of the iron = 15.4/56 = 0.275 mol
The mass of the oxygen gas = 3.6 grams
The moles of the oxygen gas = 3.6 /32 = 0.1125 mol
From the chemical equation, 4 moles of the Fe react with oxygen = 3 mol
Then 0.275 mol of the Fe will react with oxygen = 3/4 × 0.275 = 0.206 mol
Therefore, oxygen is the limiting reagent here.
The 3 mols of oxygen produced iron oxide = 2 mol
0.1124 mol of oxygen will produce iron oxide = (2/3) × 0.1125 = 27.04 g
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when 27.64 g of a hydrocarbon is burned in a bomb calorimeter, the temperature increases by 54.91c. if the heat capacity of the calorimeter is 68.5 j/c and the sample is submerged in 1000 ml of water, how much heat (in kj) was produced by the hydrocarbon combustion?
By using the data given in the text and the specific heat capacity of water and its density, we can calculate that the amount of heat produced by hydrocarbon combustion was 233.6 kJ.
The heat released by hydrocarbon combustion is absorbed by the calorimeter and the water in it. To calculate the amount of heat (Q) produced by the combustion, we are going to use the specific heat capacity of water (c = 4.186 J/g°C), the heat capacity of the calorimeter (q = 68.5 J/°C) and the difference in temperature (ΔT = 54.91 °C):
heat absorbed by the calorimeter = ΔT*q
heat absorbed by water = ΔT*c*m
Q = ΔT*q + ΔT*c*m
m - the mass of water
To obtain the mass of water, we are going to use the volume (V = 1000 mL) of water and its density (d = 1.00 g/mL):
d = m/V ⇒ m = d * V
m = 1.00 g/mL * 1000 mL
m = 1000 g
Now we can plug all the known values in the formula for Q:
Q = 54.91 °C * 68.5 J/°C + 54.91 °C * 4.186 J/g°C * 1000 g
Q = 233,614.595 J
Q = 233.6 kJ
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Synthetic materials are not found in nature and therefore they are typically developed in laboratories.
True
False
Answer: True
Explanation: Synthetic materials are not found in nature and can be created in labs using chemicals and compounds.
Which elements has the lowest ionization energy
cs, mg, cu, ge, n, s, f
which of the following statement(s) is/are true about chemical kinetics? group of answer choices chemical kinetics shows the transfer of energy in the form of heat and/or work. chemical kinetics is the branch of physical chemistry that is concerned with the direction in which a process occurs but in itself tells nothing about its rate. a reaction rate law must match the coefficients in the balanced chemical equation reaction rate can be defined as the decrease in the concentrations of reactants with time. chemical kinetics is the study of the rates of reactions.
The following two statements are true about chemical kinetics.
1. Chemical kinetics is the study of the rate of reactions.
2. A reaction rate can be defined as the decrease in the concentrations of reactants with time.
Chemical kinetics deals with the study of rate of chemical reactions. Rate of reaction is defined as the measure of the change in concentration of the reactants or the change in concentration of the products per unit time.
The reaction rates decrease with time because reactant concentrations decrease as reactants are converted to products. The rate decreases as the reaction proceeds.
A→B
A= reactant rate of reaction =-[tex]\frac{d[A]}{dt}[/tex]
B=product rate of reaction=+[tex]\frac{d[B]}{dt}[/tex]
This means that the concentration of 'A' decrease with respect to time. It can also be noted by measuring the increase in the Concentration of B with the passage of time.
Negative sign indicates the conc. of reactants decreases with time
Positive sign indicates that conc. of product increases with the passage of time .Remember rate of reaction always positive.
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Which of the following compounds contains the greatest percent by mass of nitrogen
Answer:
[tex]A\colon NH_3[/tex]
Explanation:
Here, we want to get which of the compounds have the highest percentage by mass of nitrogen
What we have to do here is to divide the mass of nitrogen atoms in the compound by the molecular mass of the compound
a) NH3
The atomic mass of nitrogen is 14 amu, the atomic mass of hydrogen is 1 amu
The molar mass is thus 14 + 3(1) = 17 g/mol
The percentage by mass of nitrogen will be
14/17 * 100 = 82.35 %
b) HCN
The atomic mass of carbon is 12 amu
Thus, we have the molar mass as
1 + 12 + 14 = 27 g/mol
Percentage of nitrogen by mass will be : 14/27 * 100 = 51.85 %
c) For N2O
The atomic mass of oxygen is 16 amu
The molar mass of the compound will be 14(2) + 16 = 44 g/mol
Percentage of nitrogen by mass will be = 28/44 * 100 = 63.64 %
d) NI3
The atomic mass of iodine is 127 g/mol
So the molar mass of the compound will be:
14 + 3(127) = 395 g/mol
Percentage by mass of nutrogen will be
14/395 * 100 = 3.54 %
From what we have, the highest percentage by mass of nitrogen is 82.35 % and that belongs to ammonia (NH3)
what is the heat of a reaction, in joules, with a total reaction mixture volume of 67.9 ml if the reaction causes a temperature change of 6.5 oc in a calorimeter? assume that the reaction mixture has a density of 1.00 g/ml and a specific heat of 4.184 j/g-oc. the calorimeter has a heat capacity of 10.0 j/oc.
The heat of reaction is 1.8 KJ. A calorimeter is a device used in calorimetry, a procedure for calculating heat capacity and measuring the heat of chemical processes or other physical changes.
How to calculate calorimeter?A calorimeter is a device used in calorimetry, a procedure for calculating heat capacity and measuring the heat of chemical processes or other physical changes. Among the most popular kinds are differential scanning calorimeters, isothermal micro calorimeters, titration calorimeters, and accelerated rate calorimeters. Calorimeter, a tool for estimating a material's heat capacity and measuring the heat produced during a mechanical, electrical, or chemical reaction. bomb thermometer.Volume of water = 67.9 mL
Since the density of water is 1.00 g/mL
Density = mass/volume
Mass of water = Density × volume
Mass of water = 1 g/mL × 67.9 mL
Mass of water = 67.9g or 0.0679 Kg
Temperature change = 6.5 oC
Specific heat capacity of water= 4.184 J/Kg
From;
H = mcθ
m = mass of water
c = heat capacity of water
θ = temperature rise
Substituting values;
H = 0.0679 Kg × 4.184 J/Kg × 6.5 oC
H = 1.8 KJ
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8. a small cylinder of helium gas for filling balloons has a volume of 2.30 l and a pressure of 1850 atm at 25oc. how many balloons can you fill if each one has a volume of 1.5 l and a pressure of 1.25 atm at 25oc?
A total of 2269 balloons of 1.5 Liters volume and 1.25 atm pressure can be filled from the cylinder of volume 2.3 Liters and 1850 atm pressure.
The volume of the Helium gas is 2.3L and the pressure is 1850 atm at 25° Celsius.
The smaller balloons that has to be filled are of volume 1.5 L at the pressure 1.25atm at the same temperature of 25° C.
Because the temperature is conserved, so, according to Boyle's law,
When temperature is constant, the pressure and volume of the gas are inversely proportional to each other.
we can write,
P₁V₁ = P₂V₂
Let us say that a total n numbers of smaller balloons can be filled, so,
P₁V₁ = n(P₂V₂)
Where,
P₁ is pressure of bigger balloon,
V₁ is the volume of the bigger balloon,
P₂ is the pressure of the smaller balloon and,
V₂ is the volume of the smaller balloon.
Now, putting all the values,
2.30 x 1850 = n(1.5 x 1.25)
n = 2269
So, a total 2269 balloons can be filled from the bigger balloon to the smaller balloons.
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If we weighed a cup of water and a spoonful of pepper separately and then stirred the pepper into the water and weighed the mixture, how do you think the weights would compare? Why? What if we did the same with sugar?
Answer:
it would be the same weight but it's ith sugar I think it would way more
the total pressure of gases a, b, and c in a closed container is 4.1 atm . if the mixture is 36% a, 42% b, and 22% c by volume, what is the partial pressure of gas c? view available hint(s)for part a the total pressure of gases a, b, and c in a closed container is 4.1 . if the mixture is 36% a, 42% b, and 22% c by volume, what is the partial pressure of gas c? 1.5 atm 1.7 atm 0.22 atm 0.90 atm
Answer:
Explanation:
so
if you take a square tlc plate and develop a compound mixture with one solvent mixture, dry the plate, and later develop it with a different solvent mixture; you can separate one set of compounds well and then separate another set of compounds well. in which directions should you develop the tlc plate with the two different solvent mixtures? this technique is often used to separate molecules of biological interest.
You should develop the TLC (thin layer chromatography) plate orthogonally (under a 90-degree angle) to the original direction of development (along its width, while the original development was along the length of the TLC plate).
This technique is called 2D TLC (two-dimensional thin layer chromatography) and is usually employed to analyze and preparatively separate very complex mixtures that cannot be separated using only one solvent system. The initial development (along the length of the TLC plate) enables crude separation into groups of compounds with similar retention factor (Rf). These groups can then be further separated using a different solvent system by developing the same TLC plate along its width.
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how many atoms are in 2.5 moles of c4h802
Answer:
1.505 × 10²⁴ atomsExplanation:
To find the number of entities in a given substance we use the formula
N = n × L
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question
n = 2.5 moles
We have
N = 2.5 × 6.02 × 10²³ = 1.505 × 10²⁴
We have the final answer as
1.505 × 10²⁴ atomsHope this helps you
exactly 25.0 ml of an aqueous solution of strontium hydroxide required 32.0 ml of 0.200 m nitric acid to neutralize it. what is the concentration of the strontium hydroxide solution? give only your numerical answer and do not include the m. for example, 0.262 or 1.25.
Ba(OH)2(aq) + 2HNO3(aq) ==> 2H2O(l) + Ba(NO3)2(aq) ... balanced equation
What is balanced equation?A chemical equation that is balanced has the same number of each type of atom on both sides of the equation. Subscripts are a component of the chemical formulas for the reactants and products that show how many atoms of the previous element there are in each.
note the stoichiometry ... 2 mols HNO3 for each 1 mol Ba(OH)2
Now we can use dimensional analysis and the noted stoichiometry to solve the problem:
32.0 ml HNO3 x 1 L/1000 ml x 0.200 mol / L = 0.0064 mols HNO3 used
0.0064 mol HNO3 x 1 mol Ba(OH)2 / 2 mols HNO3 = 0.0032 mol Ba(OH)2 present
Concentration of Ba(OH)2 = mols/L = 0.0032 mols / 0.0250 L = 0.128 M
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What atom matches this electron configuration?
1s22s22p63s2 3p64s23d104p65s24d105p66s24f145d9
Mercury
Thallium
Gold
Platinum
Answer:
Gold
Explanation:
To recognize what element this is, we can simply look at the last orbital (5d9) and go to the periodic table and see what element is in that final orbital.
We go to row 6 (because of the 6s orbital at the beginning of this row) and then we see that our 6s orbital is full with 2 electrons, then our 4f orbital is full with 14 electrons, and our 5d orbital is not full where we only have 9 electrons instead of 10.
We then go to our 5d orbital and count 9 times into that orbital and end up with our final element being Gold (Au).