i think .117018
now to get to the 20charaeactrs minimum.
he equation for the dissociation of pyridine is
C5H5N(aq) + H2O(l) ⇌ C 5H5NH+(aq) + OH-(aq) Kb = 1.9 × 10-9
Calculate the pH of a pyridine solution that has a concentration of 9.2 M. Round your answer to two decimal places.
Answer:
10.10
Explanation:
Step 1: Write the basic dissociation reaction for pyridine
C₅H₅N(aq) + H₂O(l) ⇌ C₅H₅NH⁺(aq) + OH⁻(aq) Kb = 1.9 × 10⁻⁹
Step 2: Calculate [OH⁻]
For a weak base, we will use the following expression.
[OH⁻] = √(Cb × Kb) = √(9.2 × 1.9 × 10⁻⁹) = 1.3 × 10⁻⁴ M
Step 3: Calculate pOH
We will use the definition of pOH.
pOH = -log [OH⁻] = -log 1.3 × 10⁻⁴ = 3.9
Step 4: Calculate pH
We will use the following expression.
pH = 14 - pOH = 14 - 3.9 = 10.10
Suppose you need to prepare 138.1 mL of a 0.190 M aqueous solution of NaCl. What mass, in grams, of NaCl do you need to use to make the solution
Answer:
Explanation:
· 44 g NaCl Explanation: The problem provides you with the molarity and volume of the target
The answer is rounded to two sig figs, the number of sig figs you have for the molarity of the solution.
The mass of a solute needed to prepare a solution with given volume is find by molarity. The mass of NaCl need to make a 138.1 mL solution of 0.190 M is 1.53 grams.
What is molarity ?Molarity of a solution is a term to express its concentration. Mathematically, it is the ratio of no.of moles of solute to the volume of solution in litres.
Given that, the volume of solution is 138.1 mL. One litre solution is 1000 mL. Hence, 138.1 mL is 0.1381 L. The molarity of the solution is 0.190 M. From these data we can calculate the no.of moles of NaCl as below:
no.of moles = molarity × volume of solution in L
= 0.190 M × 0.1381 L
= 0.0262 moles.
This is the no.of moles required to make the solution.
Molecular mass of NaCl = 58.4 g/mol.
Thus mass of 0.0262 moles of NaCl = 0.0262 mol × 58.4 g/mol
= 1.53 g.
Therefore, the mass of NaCl required is 1.53 g.
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which selection is an example of an electrolyte
a. potassium iodide in water
b. sucrose in water
c. pentane in octane
d. methanol in water
Answer:
i believe its A, potassium iodide in water
Explanation:
Balance the following reactions and identify the species that have been oxidized and the species that have been reduced.
CL2 +I- -------------> I2 +CL-
WO2 + H2 ---------------> W + H2O
CA + H2O -----------------> H2 + CA(OH)2
AL+ O2 --------------------> AL2O3
Answer:
Balance the following reactions and identify the species that have been oxidized and the species that have been reduced.
CL2 +I- -------------> I2 +CL-
WO2 + H2 ---------------> W + H2O
CA + H2O -----------------> H2 + CA(OH)2
AL+ O2 --------------------> AL2O3
Explanation:
Oxidation is the process where an atom loses electrons.
During oxidation, the oxidation number of the atom increases.
Reduction is the process where an atom gains electrons.
During reduction, the oxidation number of the atom decreases.
The balanced chemical equations for the given reactions are shown below:
[tex]Cl_2 +2I^- -> I_2 + 2Cl^-[/tex]
Iodine undergoes oxidation and chlorine undergoes reduction.
[tex]WO_2 +2 H_2 -> W+ 2 H_2O\\[/tex]
In this reaction, W (tungsten) undergoes reduction and hydrogen undergoes oxidation.
[tex]Ca+2 H_2O ->H_2+Ca(OH)_2\\[/tex]
Ca undergoes oxidation and hydrogen undergoes reduction.
[tex]4Al+3O_2->2Al_2O_3\\[/tex]
Al undergoes oxidation and oxygen undergoes reduction.
20. What intermolecular forces would affect the interactions of water molecules? Explain why.
Answer:
Water has strong hydrogen bond dipole-dipole intermolecular forces that give water a high surface tension and a high heat of vaporization and that make it a strong solvent
Para formar bronce, se mezclan 150g de cobre a 1100°C y 35g de estaño a 560°C. Determine la temperatura final del sistema.
Dato: Ce Cu: 0,093 cal/gºC; Ce Sn: 0,060 cal/gºC
Answer:
[tex]T_F=1029\ºC[/tex]
Explanation:
¡Hola!
En este caso, dada la información, es posible determinar que la temperatura del sistema estará entre 560 °C y 1100 °C, por lo tanto, se hará necesario establecer la suma de la energía del cobre y del estaño como cero:
[tex]Q_{Cu}+Q_{Sn}=0[/tex]
Así, podremos escribir esta ecuación en términos de masas, calores específicos y temperaturas como sigue:
[tex]m_{Cu}C_{Cu}(T_F-T_{Cu})+m_{Sn}C_{Sn}(T_F-T_{Sn})=0[/tex]
Con el fin de resolver para la temperature final:
[tex]T_F=\frac{m_{Cu}C_{Cu}T_{Cu}+m_{Sn}C_{Sn}T_{Sn}}{m_{Cu}C_{Cu}+m_{Sn}C_{Sn}}[/tex]
Así, reemplazamos las variables conocidas como se muestra a continuación:
[tex]T_F=\frac{150g*0.093cal/g\ºC*1100\°C+35g*0.060cal/g\ºC*560\°C}{150g*0.093cal/g\ºC+35g*0.060cal/g\ºC}\\\\T_F=1029\ºC[/tex]
¡Saludos!
The angular momentum quantum number (l) value of 0 indicates the ________ subshell.
Answer:
indicates the number of subshells
From the dropdowns, identify whether the compound contains ionic bonds, covalent bonds, or both. a) CBr4 [ Select ] b) copper(II) sulfate [ Select ] c) N2O3 [ Select ] d) phosphorous trichloride
Answer:
a) Covalent bonds
b) Covalent and ionic bonds
c) Covalent bonds
d) Covalent bonds
Explanation:
Metals and non-metals form ionic bonds (electrons are transferred), whereas nonmetals and nonmetals form covalent bonds.
Identify whether the compound contains ionic bonds, covalent bonds, or both.
a) CBr₄. C and Br are nonmetals. Thus, they form covalent bonds.
b) copper(II) sulfate. Sulfate contains S and O (nonmetals), which are bonded through covalent bonds. Sulfate is bonded to copper (metal) through an ionic bond.
c) N₂O₃. N and O are nonmetals. Thus, they form covalent bonds.
d) phosphorous trichloride. P and Cl are nonmetals. Thus, they form covalent bonds.
what is the molar masses for C8H10N2O4
Answer:
198.2 g/mol
Explanation:
C = 12.01 g/mol
H = 1.01 g/mol
N = 14.01 g/mol
O = 16.00 g/mol
(12.01 x 8) + (10 x 1.01) + (14.01 x 2) + (16.00 x 4) = 198.12 g/mol
A chemist fills a reaction vessel with 9.47 atm nitrogen monoxide (NO) gas, 2.61 atm chlorine (C12) gas, and 8.64 atm nitrosyl chloride (NOCI) gas at a temperature of 25.0°C. Under these conditions, calculate the reaction free energy AG for the following chemical reaction:
2NO(g) + Cl2(g) = 2NOCI (g)
Use the thermodynamic information in the ALEKS Data tab. Round your answer to the nearest kilojoule.
Answer: The Gibbs free energy change of the reaction is 2.832 kJ.
Explanation:
The relationship between Gibbs free energy change and reaction quotient of the reaction is:
[tex]\Delta G^o=-RT\ln Q_p[/tex]
where,
[tex]\Delta G^o[/tex] = Gibbs free energy change
R = Gas constant = 8.314 J/mol.K
T = temperature = [tex]25^oC=298K[/tex]
[tex]Q_p[/tex] = reaction quotient = [tex]\frac{p_{NOCl}^2}{(p_{NO}^2)\times (p_{Cl_2})}[/tex]
We are given:
[tex]p_{NOCl}=8.64atm\\p_{NO}=9.47atm\\p_{Cl_2}=2.61atm[/tex]
Putting values in above equation, we get:
[tex]\Delta G^o=-(8.314)\times 298K\times \ln (\frac{(8.64)^2}{(9.47)^2\times (2.61)})\\\\\Delta G^o=-8.314\times 298\times (-1.143)[/tex]
[tex]\Delta G^o=2831.86J=2.832kJ[/tex] (Conversion factor: 1 kJ = 1000 J)
Hence, the Gibbs free energy change of the reaction is 2.832 kJ.
Ethylene glycol flows at 0.01 kg/s through a 3-mm diameter, thin-walled tube. The tube is coiled and submerged in well-stirred water bath maintained at 25°C. If the fluid enters the tube at 85°C, what heat rate and tube length are required for the fluid to leave at 35°C?
Answer:
heat rate= 1281W
length = 15.8m
Explanation:
we have this data to answer this question with
Tmi = 85 degrees
Tmo = 35 degrees
Ts = 25 dgrees
flow rate = 25 degrees
using engine oil property from table a-5
Tm = Tmo - TMi/2 = 333k
u =0.522x10⁻²
k = 0.26
pr = 51.3
cp = 2562 J/kg.k
mcp(Tmo-Tmi) =
0.01 x 2562(35-85)
= 1281 W
we find the change in Tim
= [(35-25)-(85-25)]/ln[(35-25)/(85-25)]
= -50/ln0.167
= -50/-1.78976
= 27.9°c
we finf the required reynold number
4x0.01/πx0.003x0.522x10⁻²
= 0.04/0.00004921
= 812.8
= 813
we find approximate correlation
NuD = hd/k
NuD = 3.66
3.66 = 0.003D/0.26
cross multiply
0.003D = 3.66x0.26
D = 3.66x0.26/0.003
= 317.2
As = 1281/317x27.9
= 0.145
As = πDL
L = As/πD
= 0.145/π0.003
= 0.145/0.009429
L = 15.378
The concentration ratio of conjugate acid to conjugate base for a 20 mM solution at pH 7.0 of an amino acid is 20:1.
Required:
a. What is the pK of the side chain?
b. What amino acid might this be?
Answer:
a. 8.3= pKa of the aminoacid
b. Cysteine
Explanation:
The pH of an acid can be obtained using the H-H equation:
pH = pKa + log [A-] / [HA]
Where pH is the pH of the buffer = 7.0
pKa is the pka of the conjugate acid = ?
[A-] / [HA] is the ratio between conjugate base and conjugate acid. As the ratio of conjugate acid to conjugate base = 20:1, the [A-] / [HA] = 1/20
Replacing:
7 = pKa + log 1/20
7 = pKa - 1.30
7+1.30 = 8.3 = pKa of the aminoacid
The only aminoacid with a side chain with pKa = 8.3 is:
Cysteine. Allowing its identification.
liquid junction potential arise due to?
Answer:
liquid junction potentials
when a cell contains a boundary between two electrolytic solutions of different composition or concentration, a liquid junction potential is developed due to the "diffusion of the various components at characteristic rates in the boundary zone."
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An aqueous solution contains 0.29 M of benzoic acid (HA) and 0.16 M of sodium benzoate (A-). If the pH of this solution was measured to be 4.63, calculate the pKa of benzoic acid g
Answer:
pKa = 4.89.
Explanation:
We can solve this problem by using the Henderson-Hasselbach equation, which states:
pH = pKa + log [tex]\frac{[A^-]}{[HA]}[/tex]
In this case [A⁻] is the concentration of sodium benzoate and [HA] is the concentration of benzoic acid.
We input the given data:
4.63 = pKa + log [tex]\frac{0.16}{0.29}[/tex]
And solve for pKa:
pKa = 4.89
You used a variety of media with a NaCl concentration ranging from 0.5% to 15%. Which of these media would have the lowest water activity?
a. 0.5% NaCl
b. 15% NaCl
c. 10% NaCl
d. 5% NaCl
Answer:
Explanation:
B
Question 1 Points 3 23 and Louis immerses his left hand in a beaker containing cold water and immerses his right hand in a beaker containing warm water. Then, he immerses both his hands on a beaker containing water at room temperature. Which of the following statements are true? 1. The hand that was in hot water would feel cold. 2. The hand that was in cold water would feel hot. 3. His two hands will feel the same hotness. Que O2 and 3 0 1 and 2 o 1 and 3 1.2, and 3
Answer:look down below
Explanation:
The statements that are true about hands that are immersed in the water are:
1. The hand that was in hot water would feel cold.
2. The hand that was in cold water would feel hot.
The correct option is B 1. and 2.
What is temperature?
Temperature is the measurement of the hotness or coldness of any object. It is measured in Celsius or kelvin. Our body has nerves that feel the different temperatures of any object. The high temperature is called hot and the low temperature is called cold.
When Louis put his hand in the warm water and one hand in the cold water. He feels the temperature of both glasses of water. Then he put both hands in the normal water.
So the hand that is warm would feel the water as cold and the hand with cold water would feel the water as hot.
Thus, the correct option is B. 1. and 2.
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How many g of Al are required to produce 2.8 mol of Al2O3
Answer:
290 g Al₂O₃
General Formulas and Concepts:
Atomic Structure
Reading a Periodic TableMolesStoichiometry
Using Dimensional AnalysisExplanation:
Step 1: Define
[Given] 2.8 mol Al₂O₃
[Solve] g Al₂O₃
Step 2: Identify Conversions
[PT] Molar Mass of Al: 26.98 g/mol
[PT] Molar Mass of O: 16.00 g/mol
Molar Mass of Al₂O₃: 2(26.98) + 3(16.00) = 101.96 g/mol
Step 3: Convert
[DA] Set up: [tex]\displaystyle 2.8 \ mol \ Al_2O_3(\frac{101.96 \ g \ Al_2O_3}{1 \ mol \ Al_2O_3})[/tex][DA] Multiply [Cancel out units]: [tex]\displaystyle 285.488 \ g \ Al_2O_3[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
285.488 g Al₂O₃ ≈ 290 g Al₂O₃
Topic: AP Chemistry
Unit: Atomic Structure
How many miles are in 8.73 *10^25 atoms of boron
The correct question is: How many moles are in [tex]8.73 \times 10^{25}[/tex] atoms of boron.
Answer: There are 145 moles present in [tex]8.73 \times 10^{25}[/tex] atoms of boron.
Explanation:
According to the mole concept, there are [tex]6.022 \times 10^{23}[/tex] atoms present in one mole of every substance.
Hence, number of moles present in [tex]8.73 \times 10^{25}[/tex] atoms is calculated as follows.
[tex]Moles = \frac{8.73 \times 10^{25}}{6.022 \times 10^{23}}\\= 1.45 \times 10^{2}\\= 145 mol[/tex]
Thus, we can conclude that there are 145 moles present in [tex]8.73 \times 10^{25}[/tex] atoms of boron.
I mix together 50.0 mL of 0.100 M NaIO3, 50.00 mL of 0.100 M NaOH, and 10.0 mL of 0.100 M HIO3. What is the pH of the mixture
Answer:
pH = 12.66
Explanation:
The HIO3 reacts with NaOH as follows:
HIO3 + NaOH → H2O + NaIO3
The moles of HIO3 and NaOH added are:
Moles HIO3:
0.0100L * (0.100mol / L) = 0.00100 moles HIO3
Moles NaOH:
0.05000L * (0.100mol / L) = 0.00500 moles NaOH
As moles NaOH > Moles HIO3, the moles of NaOH that remain are:
0.00500mol - 0.00100mol = 0.00400 moles NaOH.
After the reaction you will have only NaOH and NaIO3. As NaIO3 is a salt, the pH of the solution is determined by only NaOH. Its concentration is:
Moles NaOH: 0.00500 moles NaOH
Volume: 50.0mL + 50.0mL + 10.0mL = 110.0mL = 0.110L
Molarity: 0.0455M NaOH = [OH-]
pOH = -log [OH-] = 1.34
pH = 14 - pOH
pH = 12.66pH is the measure of the hydrogen or the hydronium ion in an aqueous solution. The pH of the mixture containing sodium hydroxide is 12.66.
What is pH?pH is the potential of the hydrogen and is given as a negative log of the hydrogen concentration in the aqueous solution.
The balanced chemical reaction can be shown as:
[tex]\rm HIO_{3} + NaOH \rightarrow H_{2}O + NaIO_{3}[/tex]
Moles of iodic acid are calculated as:
[tex]\begin{aligned} \rm moles &= \rm molarity \times volume\\\\&= 0.100 \;\rm M \times 0.0100 \;\rm L \\\\&= 0.00100\;\rm moles\end{aligned}[/tex]
Moles of sodium hydroxide are calculated as:
[tex]\begin{aligned} \rm moles &= \rm molarity \times volume\\\\&= 0.100 \;\rm M \times 0.05000 \;\rm L \\\\&= 0.00500\;\rm moles\end{aligned}[/tex]
The remaining moles of sodium hydroxide are 0.00500mol - 0.00100mol = 0.00400 moles.
The pH of the mixture will be determined by sodium hydroxide, as sodium iodate is a salt.
The molar concentration of sodium hydroxide is calculated as:
[tex]\begin{aligned} \rm M &= \rm \dfrac{moles}{volume}\\\\&= \dfrac{0.00500}{0.110}\\\\&= 0.0455 \;\rm M\end{aligned}[/tex]
pH is calculated as:
[tex]\begin{aligned} \rm pOH &= \rm -log[OH^{-}] = 1.34\\\\\rm pH &= \rm 14 - pOH\\\\\rm pH &= 12.66\end{aligned}[/tex]
Therefore, 12.66 is the pH of the mixture.
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Essentially all of the mass of an atom is due to the?
nucleons
electrons.
protons
Neutrons
Answer:
nucleons
Explanation:
The answer to the question is nucleons. Because there are both protons and neutrons in the nucleon, it will be heavier. Also, protons and neutrons are much heavier than the weight of an electron, because electrons float around the atom so it is not the answer. So, our final answer is actually option A.
Using any data you can find in the ALEKS Data resource, calculate the equilibrium constant k at 25.0 celsius for the following reaction.
6Cl2(g)+2Fe2O3(s)----->4FeCl3(s)+3O2
Round answer to 2 significant digits.
Answer:
Explanation:
From the given reaction:
[tex]6Cl_{2(g)}+2Fe_2O_{3(s)} \to 4FeCl_{3(s)}+3O_2[/tex]
From the Gibbs Free Energy table at standard conditions, the value of each compound is as follows:
[tex]G_f^0 \ of \ Cl_2 = 0 \ KJ/mol[/tex] [tex]G_f^0 \ of \ Fe_2O_3 = -742.24 \ KJ/mol[/tex]
[tex]G_f^0 \ of \ Fe_2Cl_3 = -334.05 \ KJ/mol[/tex] [tex]G_f^0 \ of \ O_2 = 0 \ KJ/mol[/tex]
Now, the standard Gibb's Free energy for the given reaction can be estimated as follows:
[tex]\mathtt{\Delta G^0 = (4 *G_f^0(FeCl_3) +3*G_f^0(O_2)) - (6*G_f^0 (Cl_2) +2*G_f^0(Fe_2O_3))}[/tex]
[tex]\mathtt{\Delta G^0 = (4 *(-334.05) +3*(0)) - (6(0) +2(-742.24))}[/tex]
[tex]\mathtt{\Delta G^0 = 148.28 \ kJ/mol}[/tex]
using the following formula:
[tex]\mathtt{\Delta G^0 =-RTIn K_{eq}}[/tex]
the equilibrium constant can be determined as:
[tex]\mathtt{ In K_{eq} =\dfrac{\Delta G^0 }{-RT}}[/tex]
[tex]\mathtt{ In K_{eq} =\dfrac{148.28*10^3 J/mol }{-(8.314 \ J/k mol )*298 \ K}}[/tex]
[tex]\mathtt{ In K_{eq} =-59.85}[/tex]
[tex]\mathtt{ K_{eq} =e^{-59.85}}[/tex]
[tex]\mathtt{ K_{eq} =1.0*10^{-26}}[/tex] to 2 significant figures.
A molecule with the formula AX 4 uses ________ to form its bonds. sp2 hybrid orbitals sp3d hybrid orbitals sp3 hybrid orbitals sp3d2 hybrid orbitals sp hybrid orbitals
Answer:
sp3 hybrid orbitals
Explanation:
The formula of a molecule gives us an idea of its structure and the nature of hybrid orbitals that are involved in the formation of the molecule.
AX4 corresponds to tetrahedral geometry. If a molecule is in tetrahedral geometry, it is most likely sp3 hybridized as usual.
Hence, a molecule with the formula AX 4 uses sp3 hybrid orbitals to form its bonds
a compound has a percent compostion of carbon equal to 48.8383%, hydrogen equal to 8.1636%, and oxygen equal to 43.1981%. what is the mepirical formula
Answer:
C₂H₃O
Explanation:
From the question given above, the following data were obtained:
Carbon (C) = 48.8383%
Hydrogen (H) = 8.1636%
Oxygen (O) = 43.1981%
Empirical formula =?
The empirical formula of the compound can be obtained as follow:
C = 48.8383%
H = 8.1636%
O = 43.1981%
Divide by their molar mass
C = 48.8383 / 12 = 4.07
H = 8.1636 / 1 = 8.1636
O = 43.1981 / 16 = 2.7
Divide by the smallest
C = 4.07 / 2.7 = 2
H = 8.1636 / 2.7 = 3
O = 2.7 /2.7 = 1
Thus, the empirical formula of the compound is C₂H₃O
What is the sum of the coefficients of the balanced equation for the following reaction: FeCl2(aq) K2Cr2O7(aq) HCl(aq) ---> CrCl3(aq) FeCl3(aq) KCl(aq) H2O(l)
Answer:
The unbalanced chemical equation is
K
2
Cr
2
O
7
+HCl→KCl+CrCl
3
+H
2
O+Cl
2
Balance all atoms except H and O.
K
2
Cr
2
O
7
+10HCl→2KCl+2CrCl
3
+H
2
O+Cl
2
Assign oxidation numbers.
K
2
+6
Cr
2
O
7
+10H
−1
Cl
→2KCl+2
+3
Cr
Cl
3
+H
2
O+
0
Cl
2
The oxidation number of Cr decreases from +6 to +3. Total decrease in the oxidation number of two Cr atoms is 6. The oxidation number of Cl increases from -1 to 0. Total increase in the oxidation number of 2 Cl atoms is 2.
Balance increase in oxidation number with decrease in oxidation number by using appropriate coefficients.
K
2
Cr
2
O
7
+14HCl→2KCl+2CrCl
3
+H
2
O+3Cl
2
Balance O atoms by adding six water molecules on products side.
K
2
Cr
2
O
7
+14HCl→2KCl+2CrCl
3
+7H
2
O+3Cl
2
H atoms are balanced.
K
2
Cr
2
O
7
+14HCl→2KCl+2CrCl
3
+7H
2
O+3Cl
2
This is balanced chemical equation.
The sum of the coefficients of the products is 2+2+7+3=14
What is the empirical formula of a compound that has a pseudoformula of C3.5H8?
Answer:
The ratio of carbon and hydrogen atoms = 3.5 : 8
= 7 : 16
Then,the empirical formula is C7H16
Based on the equations below, which metal is the least active? Pb(NO3)2(aq) + Ni (s) --> Ni(NO3)2 (aq)+ Pb(s) Pb(NO3)2(aq) + Ag(s) --> No reaction Cu(
Answer:
Ni
Explanation:
An active metal is a highly reactive metal. Active metals are found high up in the activity series.
Active metals react with other metals that are lower than them in the activity thereby displacing the lower metals from a solution of their salts. This is what may have happened in the other two reactions.
Ni is the most active metal listed in the question since it can react a compounds with Pb(NO3)2(aq) to liberate Pb metal.
Which observation provided Albert Einstein the clue that he needed to explain the photoelectric effect?
Answer:
Einstein realized that the energy in electrons was caused by the frequency of light and not the intensity of light. This made him realize that he needed to explain the photoelectric effect.
Explanation:
Einstein realized that the photoelectric effect was a system that should be studied and explained in more depth, when he saw how the energy of electrons behaved in the presence of light. He saw that this energy depends entirely on the frequency of light and not on the intensity of light. From this observation, he realized that the photoelectric effect was essential for the production of an electric energy system, through light energy, such as solar energy.
It is important to note that the photoelectric effect refers to the ejection of electrons on a light surface that comes into contact with a light source.
For each of the following circumstances, indicate whether the calculated molarity of NaOH would be lower, higher or unaffected. Explain your answer in each case. a. The inside of the pipet used to transfer the standard HCl solution was wet with water.b. you added 40 mL of water to the titration flask rather than 25ml. c. The buret, wet with water, was not rinsed with NaOH solution before filling the buret with NaOH solution. d. Five (5) drops of phenolphthalein were added to the solution to be titrated rather than three (3) drops.
Answer:
a)calculated molarity of NaOH would be lower
b) calculated molarity of NaOH would be lower
c) calculated molarity of NaOH would be lower
d) calculated molarity of NaOH would be unaffected
Explanation:
Let us recall that the reaction of NaOH and HCl is as follows;
NaOH(aq) + HCl(aq) ----> NaCl(aq) + H2O(l)
Since the reaction is 1:1, when the number of moles of HCl reacting with NaOH is low due to dilution, the calculated molarity of NaOH also becomes less than it's accurate value.
When 40mL of water is added to the titration flask rather than 25ml of water, the acid is more dilute hence less number of moles of acid than necessary reacts with the base thereby yielding a less than accurate value of the molarity of NaOH.
If the burette wet with water is not rinsed with NaOH solution, the concentration of the NaOH in the burette decreases due to dilution with water and a less than accuracy value is calculated for the molarity of NaOH.
If five drops of phenolphthalein is used instead of one or two drops, there is no qualms since enough phenolphthalein may be added to ensure that a sharp end point is obtained.
Is it better to use graphite or carbon electrodes during electrolysis if I am trying to investigate volume of gas produced ?
Answer:
yes
Explanation:
it is important for electrolysis
PLEASE HELP!!!!
Which of the following lists describes characteristics of an acid? (3 points)
Bitter taste, high pH, and caustic
Sour taste, low pH, and dissolves metals
Sour taste, high pH, and dissolves metals
Slippery, low pH, and caustic
Acids have sour taste, low pH and dissolves metals.
The list that describes the characteristics of an acid is that it has sour taste, low pH, and dissolves metals.
Characteristics of an acidAn acid is a chemical substance that has the ability to donate hydrogen ions when involved in a chemical reaction.
The following are the characteristics or features of an acid:
They have a sour taste when tasted.When measured using a pH scale it is less than 7(low pH).They react with active metals to yield hydrogen gas.Therefore, the list that describes the characteristics of an acid is that it has sour taste, low pH, and dissolves metals.
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