Answer:
1) b. 4.38
2) d. 10.7
Explanation:
1) The problem tells us that [H₃O⁺] = 4.2x10⁻⁵ M, and keeping in mind that [H₃O⁺]= [H⁺], we can calculate the pH of the solution:
pH = -log[H⁺] = 4.382) First we calculate the pOH of the solution:
pOH = -log[OH⁻] = -log(4.6x10⁻⁴) = 3.33Then we calculate the pH using the following formula:
pH = 14 - pOH = 14 - 3.33pH = 10.7The pH of a solution with a concentration of 4.2x10⁻⁵ M H₃O⁺ ion is 4.38 and of a solution with a concentration of 4.6x10⁻⁴ OH⁻ ion is 10.7.
What is pH and pOH?pH of any solution is define as the negative log of the concentration of H⁺ ions and pOH is define as the negative log of the concentration of OH⁻ ions.
Given that concentration of H⁺ ions in solution = 4.2x10⁻⁵ M
pH for this solution is calculated as:
pH = -log(4.2x10⁻⁵) = 4.38
Also given that concentration of OH⁻ ions in solution = 4.6x10⁻⁴
pOH = -log(4.6x10⁻⁴) = 3.33
We know that, pH + pOH = 14.
pH = 14 - 3.33 = 10.7
Hence, value of pH & pOH is 4.38 and 10.7 respectively.
To know more about pH & pOH, visit the below link:
https://brainly.com/question/24595796
The decomposition of carbon disulfide to carbon monosulfide and sulfur is first order with k=2.8 ×10^-7 at 1000°C .What is the half-life of this reaction at 1000°C?
Answer:
2.5×10⁶ s
Explanation:
From the question given above, the following data were obtained:
Rate constant (K) = 2.8×10¯⁷ s¯¹
Half-life (t½) =?
The half-life of a first order reaction is given by:
Half-life (t½) = 0.693 / Rate constant (K)
t½ = 0.693 / K
With the above formula, we can obtain the half-life of the reaction as follow:
Rate constant (K) = 2.8×10¯⁷ s¯¹
Half-life (t½) =?
t½ = 0.693 / K
t½ = 0.693 / 2.8×10¯⁷
t½ = 2.5×10⁶ s
Therefore, the half-life of the reaction is 2.5×10⁶ s
The chart shows the bids provided by four contractors to complete a job. Which contractor is the most cost-effective? Joshua Carmen Dante Alicia
Chart for question attached
Answer:
Joshua
Explanation:
By cost-effective here, we mean the contractor that does the job best at the shortest time and lowest money cost. To get this, we calculate total cost for each contractor and then consider time for completion of the job:
Joshua charges $25 per hour for 5 hrs
Carmen charges $20 per hour for 7 hrs
Dante charges $30 per hour for 6 hrs
Alicia charges $20 per hour for 8 hrs
Joshua's cost= $25×5=$125 in 5 hours
Carmen's cost = $20×7= $140 in 7 hours
Dante's cost= $30×6=$180 in 6 hours
Alicia's cost= $20×8= $160 in 8 hours
From the above we can see that Joshua is the most cost-effective contractor given that he completes the job in less time and with less money.
HELP WILL GIVE BRAINLIEST!!
Using the following reaction, calculate the percent yield of CaO if 20.4g of CaCO3 are heated and 10.6g of CaO are actually produced
CaCO3(s) → CaO(s) + CO2(g)
Answer:
92.79%
Explanation:
The Molar mass :
Molar mass of CaC03 = (40 + 12 + (16*3)) = 100 g/mol
Molar mass of Ca0 = (40 + 16) = 56 g/mol
Theoretical yield :
20.4g CaCO3 * 56g Ca0 / 100g CaCO3
= (20.4 * 56)/100 = 11.424 CaO
The actual yield Given is : 10.6g Ca0
The percentage yield is given by :
% yield = Actual yield / theoretical yield
% yield = 10.6 g / 11.424 g * 100%
% yield = 0.9278711 * 100%
Percentage yield = 92.79%
Se trata 50 g de aluminio que posee 10% de impurezas con suficiente cantidad de ácido sulfúrico ¿qué peso de sulfato de aluminio se obtiene si el porcentaje de rendimiento fue de 70%? P.A. (uma): Al: 27, S = 32, O = 16
Respuesta:
199.5 g
Explicación:
Paso 1: Escribir la reacción balanceada
2 Al + 3 H₂SO₄ ⇒ Al₂(SO₄)₃ + 3 H₂
Paso 2: Calcular la masa pura de 50 g de Al
Aluminio tiene 10% de impurezas, es decir, 10% de 50 g = 5 g. Luego, tiene 50 g - 5 g = 45 g de Al puro.
Paso 3: Calcular la masa teórica de Al₂(SO₄)₃ obtenida a partir de 45 g de Al
La relación de masas de Al₂(SO₄)₃ a Al es 342:54.
45 g Al × 342 g Al₂(SO₄)₃/54 g Al = 285 g Al₂(SO₄)₃
Paso 4: Calcular la masa real de Al₂(SO₄)₃ obtenida
El rendimiento de la reacción es de 70%.
285 g × 70% = 199.5 g
5. Which choice best represents the relationship between wavelength and frequency?
when frequency decreases, wavelength decreases
there is no relationship
when frequency increases, wavelength increases
O when frequency decreases, wavelength increases
Match each word to its correct meaning. 1. carbon sequestration carbon dioxide, water vapor, methane, nitrogen oxides, and some CFCs that absorb heat and keep it in the earth's atmosphere 2. greenhouse effect technology used to capture the carbon released from smokestacks and store it in some part of the environment to keep it out of the atmosphere 3. greenhouse gas a term used to describe the role that greenhouse gases play in keeping the earth warm
Answer:
1. Greenhouse gas.
2. Carbon sequestration.
3. Greenhouse effect.
Explanation:
Greenhouse gases can be defined as gases that trap heat within the Earth's atmosphere. Thus, an increase in global temperature is largely caused due to an increase in the amount of greenhouse gases in Earth's atmosphere.
Some examples of greenhouse gases present in the atmosphere are methane, water vapor, carbon dioxide etc.
Matching the descriptions with their term respectively, we have;
1. Greenhouse gas: carbon dioxide, water vapor, methane, nitrogen oxides, and some CFCs that absorb heat and keep it in the earth's atmosphere
2. Carbon sequestration: it's a technology used to capture the carbon released from smokestacks and store it in some part of the environment to keep it out of the atmosphere. Thus, it's a process that is typically used for capturing and the long-term storage of atmospheric carbon dioxide in soil, ocean, plants and geologic formation, so as to reduce global warming or climate change.
3. Greenhouse effect: it's a term used to describe the negative role that greenhouse gases such as methane, water vapor, carbon dioxide etc., play in keeping the earth warm.
A helium tank has a volume of 13.0 L at a pressure of 26.5 atm. What is
the volume of the same amount of helium at a pressure of 1.25 atm?
Answer: 275.6 L
Explanation: We use Boyle's Law to solve this.
The initial pressure (P1) is 26.5, the initial volume (P1) is 13.0 L[tex]344.5/1.25[/tex], and the final pressure (P2) is 1.25. Using Boyle's Law, we plug in the values into the equation.
P1V1=P2V2
(26.5 atm)(13.0 L) = (1.25 atm) V2
As a regular equation, we solve for V2.
344.5 atm/L= (1.25 atm) V2
344.5 atm/L / 1.25 atm = V2
275.6 = V2
The atm value cancelled out and we are just left with the L value.
Select the correct answer.
A sample taken from a layer of mica in a canyon has 2.10 grams of potassium-40. A test reveals it to be 2.6 billion years old. How much
potassium-40 was in the sample originally if the half-life of potassium-40 is 1.3 billion years?
O A.
4.20 g
O B.
8.40 g
O C.
12.6 g
• D.
16.8 g
O E.
25.2 g
Answer:
8.36 g
Explanation:
From;
0.693/t1/2 = 2.303/t log (No/N)
t1/2 = half life of potassium-40
t = age of the sample
No= initial amount of the sample
N= amount of the sample at time t
Substituting values;
0.693/1.3 × 10^9 = 2.303/2.6 × 10^9 log (No/2.10)
5.33 × 10^-10 = 8.86 × 10^-10 log (No/2.10)
5.33 × 10^-10/8.86 × 10^-10 = log (No/2.10)
0.6 = log (No/2.10)
Antilog (0.6) = (No/2.10)
No = 2.10 × Antilog (0.6)
No= 8.36 g
Monodisperse polyacrylonitrile contains molecules with the general formula -(CH2CHCN)n-, where n is typically greater than 10,000. Given that a sample of monodisperse polyacrilonitrile weighs 676.8 g and contains molecules of -(CH2CHCN)n-, calculate n.
Answer:
7.68 × 10²⁴
Explanation:
Step 1: Calculate the mass of 1 molecule of the monomer CH₂CHCN
We will get the mass of the monomer by adding the masses of the elements.
mCH₂CHCN = 3 × mC + 3 × mH + 1 × mN
mCH₂CHCN = 3 × 12.01 amu + 3 × 1.01 amu + 1 × 14.01 amu = 53.07 amu
Step 2: Convert the mass of the monomer to grams
We will use the conversion factor 1 amu = 1.66 × 10⁻²⁴ g
53.07 amu × 1.66 × 10⁻²⁴ g/1 amu = 8.81 × 10⁻²³ g
Step 3: Calculate "n"
We will divide the mass of the polymer by the mass of the monomer.
n = 676.8 g / 8.81 × 10⁻²³ g = 7.68 × 10²⁴
Sometimes we can see pollutants in water – such as floating trash. What pollutants might you not “see” in water but are dangerous to living things? *
short answer please
Answer:
chemical waste, or dangerous chemicals (liquids) in general, unless they are oily
Nitrogen in plants and soil is changed into nitrogen compounds by _____.
nitrogen fixation
respiration
denitrification
photosynthesis
Answer:
A
Explanation:
because It's the process by which atmospheric nitrogen is converted either by a natural or an industrial means to form of nitrogen such as ammonia.
A student who is performing an experiment must measure out 0.02-mL of 0.50-M HCl. The most accurate piece of equipment to measure the quantity would be a?
A) 50 mL buret
B) 25 mL graduated cylinder
C) 10 mL cylinder
D) 1 mL pipet
Answer:
Choice D) 1 mL pipet
Explanation:
If you are trying to extract 0.02 mL of HCl, you are going to need a piece of equipment that can measure very small units. Thus, Choice D would be the correct answer.
Some foods undergo sterilization in order to kill bacteria living in and on the
food. What type of radiation is used in sterilization to kill bacteria?
A. Gamma
B. Alpha
C. Beta
D. Fission
Answer:
A: Gamma
Gamma rays have enough energy to kill bacteria
Una muestra de 2,5000 (g) de piedra caliza, se disuelve y se precipita el Calcio como oxalato de Calcio (CaC2O4), este precipitado se calcina transformándose en Carbonato de Calcio (CaCO3). El peso de este compuesto es de 1,2093 (g). Calcular el % de Calcio en la muestra
Answer:
[tex]\%Ca=19.378\%[/tex]
Explanation:
¡Hola!
En este caso, basado en la información dada, es posible conocer la masa de calcio en carbonato de calcio, que de hecho es la misma en la muestra, al utilizar el siguiente esquema de cálculo:
[tex]m_{Ca}=1,2093gCaCO_3*\frac{1molCaCO_3}{100.1gCaCO_3}*\frac{1molCa}{1molCaCO_3}*\frac{40.1gCa}{1molCa}\\\\m_{Ca}=0.48444gCa[/tex]
Finalmente, calculamos el porcentaje requerido como sigue:
[tex]\% Ca=\frac{0.48444g}{2.5000g} *100\%\\\\\%Ca=19.378\%[/tex]
¡Saludos!
Assuming the volume is constant, if a gas has an
initial pressure of 84.0 kPa at 30.0°C, what would
the new pressure be at 240.0°C? (Round to the
nearest whole number)
kPa
DONE
1) Intro
2 of 3
Answer:
672kP
Explanation:
Equate the initial pressure with respect the first temperature. The unknown pressure to the second temperature and you cross multiply
Answer: 142kPa.
Explanation:got it right on edge 2020
sains
baby 6 Said dan alkali
Answer:
your image is not proper
6 ways of saving energy
Answer: 21 tips: no-cost ways to save electricity
Turn off unnecessary lights.
Use natural light.
Use task lighting.
Take shorter showers.
Turn water off when shaving, washing hands, brushing teeth.
Fix that leaky faucet.
Unplug unused electronics.
Ditch the desktop computer.
Explanation:
Hope it helps you if not sorry
When an Li atom becomes an Li+ ion, the Li atom
Answer:When a lithium atom forms an Li+ ion, the lithium atom (1) gains a proton (2) gains an electron (3) loses a proton (4) loses an electron
Which ionic equation describes a redox reaction? A. Ag(+) + Cl- = AgCl B. 2H(+) + CO3(2-) = CO2 + H2O C. H(+) + OH(-) = H2O D. Zn + Cu(2+) = Zn(2+) + Cu The marking scheme of the past paper this question is from says that the answer is D but how?
Answer: The correct option is D. [tex]Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu[/tex]
Explanation:
Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously. It is known as the reaction in which the exchange of electrons takes place.
The oxidation reaction is defined as the reaction in which a chemical species loses electrons in a chemical reaction. It occurs when the oxidation number of a species increases.
A reduction reaction is defined as the reaction in which a chemical species gains electrons in a chemical reaction. It occurs when the oxidation number of a species decreases.
From the given ionic reactions:
[tex]Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu[/tex]
On the reactant side:
Oxidation number of Zn = 0
Oxidation number of Cu = +2
On the product side:
Oxidation number of Cu = 0
Oxidation number of Zn = +2
As the oxidation number of Zn is increasing from 0 to +2. Thus, it is getting oxidized. Similarly, the oxidation number of Cu is decreasing from +2 to 0. Thus, it is getting reduced. Therefore, forming a redox couple
Hence, the correct option is D. [tex]Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu[/tex]
In what way are electrons quantized?
O A. They have fixed energy values.
they
OB. They can be gained and lost.
O C. They are negatively charged.
O D. They form bonds in molecules.
Answer: The correct option is A) They have fixed energy values.
Explanation:
Electron is one of the sub-atomic particle present around the nucleus of an atom which is negatively charged.
In an atomic model, it is assumed that the electron revolves around the nucleus in discrete orbits having fixed energy levels.
These electrons when jumping from one energy level to another, some amount of radiation is either emitted or absorbed.
These fixed energy levels are given by the Bohr model and thus, the electrons are quantized.
Hence, the correct option is A) They have fixed energy values.
Answer: They have fixed energy values
Explanation: a pex
6. Which of the following could be a base in a water solution?
a. Br-
b. NH+4
c. H2O
d. NO-3
e. Ca2+
f. C2H3O-2
Answer:
h20
Explanation:
H2O is an acid and a base, and H20 is water.
PLLLLEEAASEEE HELLPP!!
What is the molarity of 150 g C6H12O6 per 0.50 L?
A. 300 mol/L
B. 75.0 mol/L
C. 1.68 mol/L
D. 0.833 mol/L
Answer: The correct option is C) 1.68 mol/L
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{Given mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (L)}}[/tex] .....(1)
Given values:
Given mass of [tex]C_6H_{12}O_6[/tex] = 150 g
Molar mass of [tex]C_6H_{12}O_6[/tex] = 180 g/mol
Volume of the solution = 0.50 L
Putting values in equation 1, we get:
[tex]\text{Molarity of solution}=\frac{150}{180\times 0.50}\\\\\text{Molarity of solution}=1.68M[/tex]
Hence, the correct option is C) 1.68 mol/L
PLEASEE HELLLPPP mE WITH THE QUESTIONS I POSTE DIL MARK U THE BRAINLIEST I SWEAAARr
Answer:
PIEASE E first write question
What is the volume of the fluid in the graduated cylinder measured to the correct degree of precision?
Use this media to help you complete the question.
43.4 mL
44.0 mL
43.42 mL
44.10 mL
Answer:
44.10
Explanation:
got it right on odessyware
What type of nuclear decay is shown by the reaction below?
A. Alpha
B. Gamma
C. Beta
O D. Fission
Answer:
C. Beta
Explanation:
A toy car that is 0.12 m long is used to model the actions of an actual size car that is 6 m long which ratio shows the relationship between the sizes of the model and the actual car ?
Answer:
The correct answer is - 1:50.
Explanation:
Given:
Model toy car = 0.12 m
Actual size of car = 6 m
The ratio of model and actual car size = ?
Solution:
We know that 1 m = 100 cm
then, Model toy car - 0.12*100 = 12 cm
and size of the actual car - 6*100 - 600 cm
Then the ratio of model and actual car size = model car size/ actual car size
= 12/600
= 1/50
Thus, the correct answer is - 1:50.
Temperature depends on the average kinetic energy of the particles in a sample. How does this help explain why a plasma-based light does not have a high temperature?
Answer:
Temperature depends on the average kinetic energy of the particles in a sample. ... The fastest particles have the greatest mass. Most particles in the plasma are heavy and slow. The fastest particles transfer most of their energy through collisions
Answer:
C. Most particles in the plasma are heavy, slow, and very low density.
Explanation:
Correct on Edge 2022!!!
Good luck everyone, you got this! Have a great day!
Differentiate between nuclear fusion and fission .
Answer:
Explanation:
the difference is below:
Given the reaction:
Sn2+ (aq) + 2Fe3+ (aq) → Sn4+ (aq) + 2Fe2+ (aq)
The oxidizing agent in this reaction is?
A Sn2+
B Fe3+
C Sn4+
D Fe2+
Need help asap - There is an error in the rate-determining step of the following proposed mechanism.
Slow step: CH3(g) + Cl2(g) → CH3(g) + HCl(g) and the rate rule is k1 = [CH4][Cl2]
Fast step: CH3(g) + Cl2(g) → CH3Cl(g) + Cl–(g) and the rate rule is k2 = [CH4][Cl2]
Overall : CH4(g) + 2Cl2(g) → CH3Cl(g) + HCl(g) + Cl–(g)
Which shows the correct rate-determining step for the mechanism?
CH4(g) + 2Cl(g) → CH3Cl(g) + HCl(g) + Cl–(g)
CH4(g) + Cl2(g) → CH3(g) + HCl(g) and the rate rule is k1 = [CH4][Cl2]
CH4(g) + Cl2(g) → CH3Cl(g) + Cl–(g) and the rate rule is k2 = [CH4][Cl2]
CH3(g) + 2Cl2(g) → CH3Cl(g) + Cl–(g) and the rate rule is k2 = [CH4][Cl2]
Answer:
CH4(g) + Cl2(g) → CH3(g) + HCl(g) and the rate rule is k1 = [CH4][Cl2]
Explanation:
Firstly, we must remember that the substitution reaction between halogens and alkanes to yield halogenoalkanes does not proceed by ionic mechanism rather it proceeds by free radical mechanism.
Now, if we look at the rate determining step as shown in the question, the elementary reaction equation of that step is not balanced.
Hence, the correct elementary reaction equation for the rate determining step and the rate law is; CH4(g) + Cl2(g) → CH3(g) + HCl(g) and the rate rule is k1 = [CH4][Cl2]