Answer:
pH = -log[H⁺] = -log(4.75 x 10⁻⁷) = -(- 6.32 ) = 6.32
Explanation:
Given 4.3 x 10⁻⁷M H₂CO₃ (Ka1 = 4.2 x 10⁻⁷ & Ka2 = 4.8 x 10⁻¹¹)
Note: The Ka2 value for the 2nd ionization step is so small (Ka2 = 4.8 x 10⁻¹¹) It will be assumed all of the hydronium ions (H⁺) come from the 1st ionization step.
1st Ionization step
H₂CO₃ ⇄ H⁺ + HCO₃⁻
C(initial) 4.3 x 10⁻⁷ 0 0
ΔC -x +x +x
C(final) 4.3 x 10⁻⁷ - x x x
Note: the 'x' value in this analysis can not be dropped as the Conc/Ka value is less than 10². In this case he C/Ka ratio* (4.3E-7/4.2E-7 ≈ 1) is far below 10².
So, one sets up the equilibrium equation to be quadric and the x-value can be determined.
Ka1 = [H⁺][HSO⁻]/[H₂SO₃] = (x)(x)/(4.3 x 10⁻ - x) = x²/(4.3 x 10⁻⁷ - x) = 4.2 x 10⁻⁷
=> x² = 4.2 x 10⁻⁷(4.3 x 10⁻⁷ - x)
=> x² + 4.2 x 10⁻⁷x - 1.8 x 10⁻¹³ = 0
a = 1, b = 4.2 x 10⁻⁷, c = - 1.8 x 10⁻¹³
x = b² ± SqrRt(b² - 4(1)(-1.8 x 10⁻¹³ / 2(1) = 4.75 x 10⁻⁷
x = [H⁺] = 4.75 x 10⁻⁷
pH = -log[H⁺] = -log(4.75 x 10⁻⁷) = -(- 6.4 ) = 6.4
______________________
* The Concentration/Ka-value is the simplification test for quadratic equations used in Equilibrium studies. If the C/Ka > 100 then one can simplify the C(final) by dropping the 'x' if used in this type analysis. However, if the C/Ka value is < 100 then the x-value must be retained and the solution is determined using the quadratic equation formula.
for ax² + bx + c = 0
x = b² ± SqrRt(b² - 4ac) / 2a
A building is found to be losing heat to the outside during the winter months. Which would be the best solution to correct this design problem?
increase amount of heating
increase surface area of walls
increase number of windows
increase thickness of insulation
no link or I will report
Answer:
increase thickness of insulation
Explanation:
don't increase amount of heating because that's difficult and not efficient.
don't increase surface area of walls because that makes heat be lost quicker.
don't increase windows because windows lose heat worse than walls.
increase thickness of insulation because it's the most effiecient and effective method of keeping heat.
This gland of the endocrine and digestive systems produces insulin to help control the body's sugar levels and enzymes which aid in digestion.
Answer:
Pancreas.
Explanation:
Living systems are self-organized life forms and are known to be very much interactive with their surroundings or environment. Also, living systems are dependent on the flow of information, matter and energy at various levels.
Some examples of living systems in organisms are respiratory system, nervous system, digestive system, and circulatory system.
Additionally, living systems comprises of the following components; cells, organs, muscle, tissues, blood, etc.
An endocrine system refers to a series of ductless glands and organs responsible for the production and secretion of hormones that are used by the body for the performance of various functions such as metabolism, controlling growth, reproduction, mood, sleep, etc. These hormones are secreted directly into the circulatory system (blood) and then transported to the organs and tissues in the body.
Pancreas is one of the glands of the endocrine and digestive systems that produces insulin to help control the body's sugar levels and enzymes which aid in digestion.
How much heat, in kJ, is released when 6 mol of water at 0°C freezes to ice at 0°C if ΔHsolid for water = –6.01 kJ/mol?
Answer:
12.3 kJ
Explanation:
For a given substance, the molar heat of fusion basically tells you one thing from two perspectives
how much heat is needed in order to melt one mole of that substance at its melting point
how much heat must be removed in order to freeze one mole of that substance at its freezing point
It is very important to realize that the molar enthalpy of fusion will carry a positive sign when you're dealing with melting and a negative sign when you're dealing with freezing.
Which of the following is true about limiting and excess reagents?
Links are reported
Answer:
the first one
Explanation:
I take this subject
Question 24 of 33
Which of the following pairs of elements will form covalent bonds with each
other?
The Periodic Table
A. Magnesium (Mg) and oxygen (0)
B. Chromium (Cr) and zinc (Zn)
O
C. Silicon (Si) and nitrogen (N)
D. Potassium (K) and bromine (Br)
The elements that will form covalent bonds are Silicon (Si) and nitrogen (N), option C.
What are covalent bonds?A covalent bond is formed between two atoms by the mutual sharing of one or more pairs of electrons. The two atomic nuclei attract these electrons at the same time. When the difference in electro-negativities of two atoms is too small for electron transfer to form ions, a covalent bond forms.
Hydrogen (H₂) is a molecule with a single covalent bond as well as Halogens like Fluorine (F), Chlorine (Cl), Silicon (Si) and nitrogen (N).
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In your own words, describe the difference between Thermal Energy and Heat.
Answer:
Heat is the flow of thermal energy between two objects of different temperature whereas the thermal energy tells about how much is the transfer of energy due to temperature difference between two bodies. Hence thermal energy in transit gives heat
HURRY WILL GIVE BRAINLIETS How are proteins and nucleic acids related? They both provide energy. They both carry genetic information. The structure of proteins is determined by nucleic acids. The subunits of nucleic acids are also the subunits of proteins.
Answer: the answer is “C”
Explanation:
Took the T E S T
For a reaction to be in equilibrium.... *
A. concentration of reactants and products remain constant
B. concentration of reactants and products must be the same
C. the rate of forward reaction is not equal to the rate of backward reaction.
Answer: C) the rate of forward reaction is not equal to the rate of backward reaction. This should be the answer.
Explanation:
1
The table gives the composition of three particles
particle
number of
protons
number of
electrons
number of
neutrons
А
15
16
B
15
16
с
15
17
(a) What is the evidence in the table for each of the following?
(i) Particle A is an atom.
(ii) A, B and C are all particles of the same element
Answer:
the answer is wurkey churkey since the birdy is really really cute
Explanation:
if the birdy was not squishy then it would have died already?!?!?
Is the kool-aid man the jar or the liquid?
I know that this is for school but like i need to know
Answer:
I think both
Explanation:
Please help me!!!!!!!!! :-]
In any engineering design problem, the first step is to understand the problem and identify one or more possible solutions. In this task, you’ll analyze the problems you face as the chemical engineer challenged with setting up the ammonia-making process. Recall the chemical equation for producing ammonia:
N2 + 3H2 ⇌ 2NH3 + energy
1.Explain the problem surrounding the ammonia-making process in terms of chemical equilibrium.
Answer:
Explanation:
About 2,070 results (0.60 seconds)
Answer is: at lower temperatures the reaction rate would decrease. The lower is the temperature, the slower the reaction becomes. ... Because this is exothermic reaction (enthalpy is less than zero), at lower temperatures, the equilibrium is in favor of ammonia, but the reaction doesn't proceed at a detectable rate.
Hi,
let us go through the question again
N2 + 3H2 ⇌ 2NH3 + energy
Explain the problem surrounding the ammonia-making process in terms of chemical equilibrium.
So I would approach this question on the basis of effect of each of the reactants and products concentration on the equilibrium synthesis of ammonia.
If the concentration of any reactant is increased, the yield of ammonia is increased.
If the concentration of ammonia is reduced by removing it as it forms, the yield will as well be increased.
This reaction also yields heat meaning it is an exothermic reaction, so when we increase the temperature, the yield will be reduced. Hence it is favored by low temperature.
Select whether the statement is for Speed, Velocity, or Acceleration.
The earth travels at 30 kilometers per second.
Velocity
Speed
Acceleration
Answer:
I think that the statement is relative to speed because it is saying km per second.
Answer:
Speed
Explanation:
How many grams of Carbon Dioxide can be produced by the complete combustion of 140.0 grams of propene; C3H6? If the actual yield turns out to be 200.0 grams of carbon dioxide, what is the percent yield?
Answer:
2 C3H6 + 9 O2 6 H2O + 6 CO2
Theo. yield is 440.0 g CO2, % yield = 45.45% Explanation: hope it helps here for ur service
439.16 g of carbon dioxide is produced by complete combustion of 140 g of propene. The percent yield is 45.54%.
What is combustion?Combustion is defined as a high temperature exothermic reaction between a fuel which acts as a reductant and an oxidant which is usually atmospheric oxygen.It does not result in fire as the flame is visible only when substance which undergoes combustion vaporizes.
For combustion reactions to take place stoichiometry is followed according to which mass of reactants or products obtained or required is calculated.
2 C₃H₆ + 9 O₂ [tex]\rightarrow[/tex] 6 CO₂ + 6 H₂O
Here 2 molecules of propene react to give 6 molecules of carbon dioxide.
∴ for 140 grams of propene 140×264/84.16=439.16 g of molecules of CO₂ are produced.
Percent yield is calculated by dividing observed yield by theoretical yield which gives 45.54% according to this example.
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How are molecules, compounds, and substances related?
Answer:
Molecule is the general term used to describe any atoms that are connected by chemical bonds. Every combination of atoms is a molecule. A compound is a molecule made of atoms from different elements. All compounds are molecules, but not all molecules are compounds.
Explanation:
i hope you mark me the brainliest
Coniferous forests grow in a wide range of climates, from the coldest polar regions to the warmest tropical regions and everything in between. Circle True or False.
The answer is true, yw.
Coniferous forests grow in a wide range of climates, from the coldest polar regions to the warmest tropical regions and everything in between. This statement is true.
What are conifers ?Conifers are a type of gymnosperm plants bearing cone like structures in which the seeds are located. Don't be fooled by the fact that coniferous woods are widespread around the world. Some of the wildest trees in the world can be found there.
Hyperion, a coastal redwood tree, is the tallest tree in the world, reaching a height of 379 feet, equivalent to a 35-story structure. From Siberia to Canada, coniferous rainforest biomes can be found. They have cold winters and warm to hot summers.
Temperatures in coniferous forests are quite low all year long. Summertime temperatures range from -7°C to 21°C, while the average wintertime temperature ranges from -54°C to -1°C. Hence, the statement is true.
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what type of wave moves the particles parallel to the motion of the wave
a.electromagnetic
b. longitudinal
c. transverse
d.water
Answer is in a ph[tex]^{}[/tex]oto. I can't attach it he[tex]^{}[/tex]re, but I uploaded it to a fi[tex]^{}[/tex]le hosting. link below! Good Luck!
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1.The symbol of an atom changes when the number of _______
changes.
2.The net charge of an atom depends on ___________ and
_________.
3.The atom is neutral when ________ and _________ are equal.
4.The mass number of an atom depends on __________ and
_________.
Answer:
1. proton
2. electrons and protons
3. protons and electrons
4. protons and neutrons
Explanation:
Larissa is making sautéed purple cabbage. First, she washes and cuts the cabbage into long thin strands. Then, she puts a
pan on the stove and adds butter. She allows the butter to melt and turn to liquid. Next, she adds the cabbage to the butter
sprinkles some salt on it, and stirs it. Larissa watches as the cabbage sizzles, releases steam, and softens. To finish the side
dish, she adds a squeeze of lemon juice to it, which causes it to change from purple to pink. Finally, Larissa empties the
cabbage into a bowl and puts it on the dinner table.
Which of the events involves a chemical reaction?
O Larissa adds butter to a pan and allows it to melt and turn to liquid.
O Larissa adds a squeeze of lemon juice to the cabbage, and it turns pink.
O Larissa watches as the cabbage sizzles, releases steam, and softens.
O Larissa washes and cuts some purple cabbage into long thin strands.
O Larissa empties the cabbage into a bowl and puts it on the dinner table.
O Larissa adds the cabbage to the butter with a sprinkle of salt and stirs it.
Answer:
When she adds lemon juice
Explanation:
I believe that it is when she adds lemon juice. Lemon juice is an acid, which causes a chemical reaction. It turns from purple to pink because of the acid. Lmk if it's right but I'm 99.9% percent certain it is correct.
The molar mass of element X is 42.3 grams per mol and the molar mass for
element Y is Y 96.7 grams per mol. What is the empirical formula for a substance
containing a mass composition of 52.2% X and the remainder Y?
Answer:
X5Y2
Explanation:
% composition of X = 52.2%
% composition of Y = (100 - 52.2) = 47.8%
This means that there are 52.2g of X and 47.8g of Y in the compound
To calculate the empirical formula of the compound, we first convert the gram value to mole value by dividing by their molar masses.
X = 52.2g/42.3g/mol = 1.234mol
Y = 47.8g/96.7g/mol = 0.494mol
Next, we divide each mole value by the smallest value (0.494mol)
X = 1.234mol ÷ 0.494mol = 2.49
Y = 0.494mol ÷ 0.494mol = 1
We multiply each value by 2
X = 2.49 × 2 = 4.98
Y = 1 × 2 = 2
The simple ratio of X:Y is 5:2, hence, their empirical formula is X5Y2.
Drag and drop the labels provided into the boxes below to explain how the Earth-Sun-Moon system results in these seasons on Earth.
___ act as an energy source? (From work bank)
Explanation:
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1) Calcula la masa molecular para las siguientes sustancias
f) Mg3(PO4)2
g) Cu(NO2)3
h) C5H12
i) (NH4)4 As2O7
j) I2O7
2)Halla la composición porcentual de cada una de las siguientes sustancias
- H3PO4
• HIO3
• H2C2O4
• C3H6O3
• NH3
• KBr
Porfavor es para mañana mismo
You place a balloon in a closed chamber at standard temperature and pressure (STP). You triple the chamber pressure.
What happens to the balloon?
The volume stays the same.
The volume increases to three times its original volume.
The temperature must also change for the volume to change.
The volume decreases to one-third of its original volume.
Answer:
it pops?
Explanation:
HI dissociates to form 12 and Hz: 2HI(g) → H2(g) + 12(9) If the concentration of Hl changes at a
rate of -0.45 mol L's? what is the rate of appearance of 12(g)?
Based on the rate of disappearance of HI, the rate of appearance of I₂ is 0.225 mol/L/s.
What is rate of reaction?
The rate of a reaction is the rate at which reactant molecules are converted to product or the rate at which product molecules are formed.
Rate of reaction = change in concentration of reactant or product/timeFrom the equation of the reaction, 2 moles of HI produces 1 mole of I₂.
The rate of disappearance of HI is -0.45 mol/L/s
The rate of appearance of I₂ will be 0.45/2 mol/L/s = 0.225 mol/L/s.
Therefore, the rate of appearance of I₂ is 0.225 mol/L/s.
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A piece of metal is composed of atoms. Each atom in the metal contains 29 protons. How is the metal classified?
Answer:
Explanation:
The metal is classified as a transition metal or transition element. In particular, this atom is Copper it has an atomic number of 29 which we know by the number of protons. The number of protons in an atom is the same as the atomic number.
Answer:
Copper
Explanation:
Each atom in the metal contains 29 protons.
Write two paragraphs about what would happen if your whole body was put in a low pressure environment ?
Answer:
Reduced air pressure also has a serious effect on the human body. Reduced air pressure means that there is less oxygen available to the body. For lungs to inflate, the air pressure in your lungs has to be less than the air outside the lungs. This is because air moves from high-pressure areas to low-pressure areas.
Explanation:
Reduced air pressure also has a serious effect on the human body. Reduced air pressure means that there is less oxygen available to the body. For lungs to inflate, the air pressure in your lungs has to be less than the air outside the lungs. This is because air moves from high-pressure areas to low-pressure areas.
Is there massless ness in space?Why?
which of the following would remain a liquid longest as the temperature continues to drop? propane, octane, hexane, ethane
Pls help! DO NOT GIVE ME A LINK AS AN ANSWER!
Recall the equation M, V1 = M2V2. Based on the presence of this amount of copper sulfate, complete the table to predict the concentration of the solution as water is added to the tank or removed from it. Don't actually change the amount of water in the tank yet. Type the correct answer in each box. Use numerals instead of words. Express each answer to two significant figures e. Volume (L) Concentration (mol/l) 1.0 0.80 0.60 0.50 0.20
Answer:
(top to bottom)
0.50
0.63
0.83
1.0
1.3
2.5
Explanation:
Answer: Answers are from top to bottom (Edmentum)
0.50
0.63
0.83
1.0
1.3
2.5
Explanation: