Answer:
C. II, III, IV, and V.
Explanation:
Acid buffer is generally formed by the combination of a weak acid as well as the salt of the conjugate base.
Basic buffer is formed the combination of a weak base and also the salt of the conjugate acid.
On dilution the ration of the concentration terms of the salt and weak acid/base does not change. Hence the pH of the buffer solution does not change.
When acid or base is added to buffer, it resists changes in the pH.
Therefore, option (C) is correct.
Caffeine is a compound found in some natural coffees and teas and in some colas. a. Determine the empirical formula for caffeine, using the following composition of a 100.00-g sample. 49.47 grams of carbon, 28.85 grams of nitrogen, 16.48 grams of oxygen, and 5.20 grams of hydrogen b. If the molar mass of caffeine is 194.19 g/mol, calculate its molecular formula.
Answer: The molecular formula will be [tex]C_8N_4H_{10}O_2[/tex]
Explanation:
Mass of C= 49.47 g
Mass of N = 28.85 g
Mass of O = 16.48 g
Mass of H = 5.20 g
Step 1 : convert given masses into moles.
Moles of C =[tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{49.47g}{12g/mole}=4.12moles[/tex]
Moles of N =[tex]\frac{\text{ given mass of N}}{\text{ molar mass of N}}= \frac{28.85g}{14g/mole}=2.06moles[/tex]
Moles of O =[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{16.48g}{16g/mole}=1.03moles[/tex]
Moles of H =[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{5.20g}{1g/mole}=5.20moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C = [tex]\frac{4.12}{1.03}=4[/tex]
For N = [tex]\frac{2.06}{1.03}=2[/tex]
For O =[tex]\frac{1.03}{1.03}=1[/tex]
For H = [tex]\frac{5.20}{1.03}=5[/tex]
The ratio of C : N: O: H = 4: 2: 1: 5
Hence the empirical formula is [tex]C_4N_2OH_5[/tex]
The empirical weight of [tex]C_4N_2OH_5[/tex] = 4(12)+2(14)+1(16)+5(1)= 97 g.
The molecular weight = 194.19 g/mole
Now we have to calculate the molecular formula.
[tex]n=\frac{\text{Molecular weight}}{\text{Equivalent weight}}=\frac{194.19}{97}=2[/tex]
The molecular formula will be = [tex]2\times C_4N_2H_5O=C_8N_4H_{10}O_2[/tex]
5. What type of level detector is not affected by the liquid's viscosity, density, conductivity or color and
is very accurate?
a. Radiation
b. lonization
c. Photoelectric
d. Infrared
For each of the following compounds, decide whether the compound's solubility in aqueous solution changes with pH. If the solubility does change, pick the pH at which you'd expect the highest solubility.
a. Ca(OH)2
b. CuBr
c. Ca3(PO4)2
Answer:
1. Ca(OH)₂ : Yes
Highest solubility = pH of 2
2. Cu Br : Yes
Highest solubility = pH of 4
3. Ca₃(PO₄)₂ : Yes
Highest solubility = pH of 2
Explanation:
From the common ion effect, the solubility of an ionic compound in a solution which already contains one of the ions in that compound will reduce. This is because, when an external stress is placed on a system in equilibrium, the equilibrium position will shift to remove the effect of that stress. Therefore, when more of the same ions are added to a solution already containing that ion, equilibrium will shift towards removal of the ion, thereby reducing solubility.
1. For Ca(OH)₂:
Ca(OH)₂ is a fairly soluble ionic compound whose dissociation equation is given below:
Ca(OH)₂ (s) ----> Ca²+ (aq) + 2 OH- (aq)
Increase in pH will result in addition of more OH- ions, therefore, its solubility will decrease. On the other hand, a decrease in pH will remove OH- ions, thereby increasing solubility. The pH of highest solubility is 2.
2. For CuBr:
CuBr is a slightly acidic salt as it is salt of a strong acid, HBr and a weak base Cu(OH)₂. Hydrolysis of the salt will result in an acidic medium:
2 CuBr (s) + 2 H₂O (l) ----> 2 HBr (aq) + Cu(OH)₂ (aq).
Thus, an increase in pH will result in an increase in the solubility of CuBr due to the removal of H+ ions. The highest solubility will be at pH of 4.
3) For Ca₃(PO₄)₂
Calcium phosphate is a salt of slightly basic salt as it is a salt of a weak acid, H₃PO₄ and stronger base Ca(OH)₂.
Hydrolysis of the salt will result in a basic medium:
Ca₃(PO₄)₂ (s) + 6 H₂O (l) ---> 3 Ca(OH)₂ (aq) + 2 H₃PO₄ (aq)
Therefore, its solubility increases with decrease in pH due to the removal of OH- ions. The highest solubility will be at pH of 2.
What type of reaction is illustrated below?2H1 --> H2 + 12
Answer:
Decomposition reaction.
Explanation:
2HI —> H₂ + I₂
From the above equation, we can see clearly that HI undergoes a reaction to produce H₂ and I₂ which are the elements that make up HI.
Therefore, the equation illustrated above is a decomposition reaction because HI breaks into H₂ and I₂
NOTE: Decomposition reaction is a reaction in which a compound splits or breakdown into two or more simple elements or compound.
what are super fuels? Describe both types with examples. In your view, what makes super fuels?
[tex]\bcancel{\huge\pink{\fbox{\tt{࿐αɴѕωєя࿐}}}}[/tex]
Super fuel or high performance fuel is petrol with a higher octane rating. Most standard brands of fuel have a 95 octane rating. But super fuel typically has a higher rating - around 98 - which can make the engine work more efficiently and improve performance.A que se denomina función química
En química, el grupo de algunas sustancias compuestas que poseen propiedades químicas semejantes, denominadas propiedades funcionales, recibe el nombre de función química. ... Además están divididas en ácidos, bases, sales y óxidos; y funciones orgánicas que son las relativas a los compuestos orgánicos.
BRAINLIST
The pH of a solution can be calculated using which formula?
Answer:
The formula for calculating pH is pH=−log[H_3O+ ]
pH is the negative logarithm (to base 10) of hydronium ion concentration
The pH Formula can also be expressed as
PH= - log[H+ ]
Fish need about 5 ppm oxygen dissolved in water to survive. Will water with 5 mg oxygen per
liter sustain the fish?
5mg in liter is 5 ppm
Explanation: 1 ppm is one part per million.
1 ppm is 1 mg is one part of million from 1 kg = 1000 000 mg
1 litre water is 1. Kg.
In the following reaction, if you wanted to produce more hydrochloric acid (HCl), what should you do? (2 points)
4HCl + O2 ⇄ 2H2O + Cl2
a. add more H2O
b. add more O2
c. remove H2O
d. remove Cl2
Answer:
Add more H2O
Explanation:
Took the test
If you wanted to produce more hydrochloric acid (HCl), you should add more [tex]H_2O[/tex] to 4HCl + [tex]O_2[/tex] ⇄ 2[tex]H_2O[/tex] + [tex]Cl_2[/tex]. Hence, option A is correct.
What is hydrochloric acid?Hydrochloric acid [[tex]H^+[/tex]](aq) [tex]Cl^-[/tex](aq) or [tex]H_3O^+ Cl^-[/tex]], also known as muriatic acid, is an aqueous solution of hydrogen chloride.
For instance, adding a strong acid such as HCl to water results in the reaction HCl + [tex]H_2O[/tex] → [tex]H_3O^+[/tex] + [tex]Cl^-[/tex].
In other words, the proton ([tex]H^+[/tex]) from the acid binds to neutral water molecules to form [tex]H_3O^+[/tex] raising the concentration of [tex]H^+[/tex].
Hence, option A is correct.
Learn more about hydrochloric acid here:
https://brainly.com/question/4902679
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Vishwanath had some money. he spent 3 upon 4 part of money to buy goods for his birthday,1 upon 5 part of money give to his sister and the rest of Rs.40 to mother how much did he have at first
Answer:
The correct answer is - 800.
Explanation:
Given:
Total amount = ? or assume x
spend in buying birthday item = 3/4 of x
given to sister = 1/5 of x
remaining to mother = 40
solution:
the remaning amount = x- (3x/4+x/5) = 4=
=> x- 19x/20 = 40
=> x = 20*40
=> x = 800
thus, the correct answer is = 800
A solution is prepared by dissolving 0.23 mol of hypochlorous acid and 0.27 mol of sodium hypochlorite in water sufficient to yield 1.00 L of solution. The addition of 0.05 mol of HCl to this buffer solution causes the pH to drop slightly. The pH does not decrease drastically because the HCl reacts with the ________ present in the buffer solution. The Ka of hypochlorous acid is 1.36 × 10-3.
Answer:
hypochlorite ion
Explanation:
The hypochlorous acid, HClO, is a weak acid with Ka = 1.36x10⁻³, when this acid is in solution with its conjugate base, ClO⁻ (From sodium hypochlorite, NaClO) a buffer is produced. When a strong acid as HCl is added, the reaction that occurs is:
HCl + ClO⁻ → HClO + Cl⁻.
Where more hypochlorous acid is produced.
That means, the HCl reacts with the hypochlorite ion present in solution
Hi can someone please help me with this. I would really appreciate it. It’s kind of urgent. Thank u so much!
Answer:
a) The system is in equilibrium
b) No other force is acting on the system
Explanation:
a) The forces in a system is balanced until and unless there is equal and opposite force acting on the system. In this image the upward force is equal to the downward force on the book and the table and hence it is in equilibrium
b) An object which is in static mode, produces downward force because of weight and in response to that a normal reaction is produced in upward direction. Apart from these two forces, no other force is acting on this book and table system.
how can CN carry negative charge
Answer:
Cyanide contains two atoms having carbon and nitrogen. Which are bonded through two two pi and one sigma bond by sharing of the electron . As a result one lonepair of electron remains in Cyanide. Hence Cyanide have a negative charge.
Explanation:
#sasha2. How many chlorine atoms are in 4 moles of chlorine?
Answer:
4
Explanation:
Hey can someone pls help me answer these questions? It should be easy maybe. It’s just science. The question just won’t to know where you would put the arrow above to show the motion of the plates. Where would I put it?
Can someone help me please!!
Answer:
1. AgNO₃ (aq) + NaCl (aq) ----> NaNO₃ (aq) + AgCl (s)
2. Li₂SO₄ (aq) + BaCl₂ (aq) ----> 2 LiCl (aq) + BaSO₄ (s)
3. 2 NaOH (aq) + MgCl₂ (aq) ----> 2 NaCl (aq) + Mg(OH)₂ (s)
Explanation:
The reaction involving the mixing of two soluble solutions to produce a precipitate is known as a precipitation reaction.
A precipitation reaction is double-replacement reaction (a reaction that exchanges the cations or the anions of two ionic compounds) in which one product is a solid precipitate.
Precipitation reactions at useful in the identification of various ions present in a solution. In order to predict the reactions that will produce a precipitate, solubility rules as given in the solubility table below can be used.
From the tables, the reactions that will produce a precipitate, as well as their balanced molecular equations are as follows:
1. AgNO₃ (aq) + NaCl (aq) ----> NaNO₃ (aq) + AgCl (s)
2. Li₂SO₄ (aq) + BaCl₂ (aq) ----> 2 LiCl (aq) + BaSO₄ (s)
3. 2 NaOH (aq) + MgCl₂ (aq) ----> 2 NaCl (aq) + Mg(OH)₂ (s)
What are the 4 different materials that come together to make up a bone?
Answer:
calcium, mineral hydroxyapatite, protein collagen and the tough fibrous component of tendons and ligaments
Explanation:
hope this helps :)
Which product is often derived from the natural environment?
Answer:
coal, cotton, chinese tradictional medicine
Which is a correct comparison between the modern quantum model and John Dalton’s model of the atom?
Answer:
No comparison => John Dalton did NOT postulate an atomic structure.
Explanation:
Dalton's postulates are based upon generalizations of observable phenomena. Micro structure was not proposed. The atomic structure that's accepted in the scientific community evolved from conclusions of ...
Thompson's raisen pudding model => electrons suspended in a positive matrix
Rutherford's shell model => dense positive nucleus surrounded by an electron cloud. (No fine structure postulated)
Bohr Concentric Ring Model => electrons orbiting a positive nucleus in discrete energy levels much like planets orbiting the sun.
Schrodinger - Dirac Quantum Models => electrons occupying specific orbital energy levels as based upon statistical wave mechanics.
Many tall trees grow in a forest. Only a few small plants grow underneath the trees. Why is this so?
Answer:
Because as more and more trees are tall, they end up blocking the sun to the smaller vegetation and so many plants end up dying or they evolve to grow taller and taller as a way to stay alive.
Explanation:
Calculate the pH of a solution with [H+] = 1.8 x 10^-5 M
Answer:
4.74
Explanation:
pH= -log[H+]
pH= -log(1.8 x 10^-5)= 4.74
2 CO + O2 → 2 CO2, how many grams of oxygen is required to produce 1.0 mole of CO2?
Answer:
16 g
Explanation:
Step 1: Write the balanced equation
2 CO + O₂ → 2 CO₂
Step 2: Calculate the moles of O₂ required to produce 1.0 moles of CO₂
The molar ratio of O₂ to CO₂ is 1:2.
1.0 mol CO₂ × 1 mol O₂/2 mol CO₂ = 0.50 mol O₂
Step 3: Calculate the mass corresponding to 0.50 moles of O₂
The molar mass of O₂ is 32.00 g/mol.
0.50 mol × 32.00 g/mol = 16 g
Zn(s), Zn(NO3)2 (0.3 M) || Cu(s), CuCl2 (0.5 M)
(Need help solving these questions, so I can solve the rest of the questions like this in my lab. It is greatly appreciated. Thank you)
2. Write the half reactions that occur at the anode and cathode in this electrochemical cell. Annotate which half reaction occurs at the anode and the cathode.
3. Write the overall balance reaction of this electrochemical cell.
4. Calculate E°cell of this electrochemical cell. (include units)
5. Calculate the reaction quotient (Q) of this reaction.
6. Calculate the expected Ecell for this reaction
Answer:
See Explanation
Explanation:
At the anode;
Zn(s) -----> Zn^2+(aq) + 2e
At the cathode;
Cu^2+(aq) + 2e ------> Cu(s)
Overall electrochemical reaction;
Zn(s) + Cu^2+(aq) ------> Zn^2+(aq) + Cu(s)
E°cell = E°cathode - E°anode
E°cell = 0.34 - (-0.76)
E°cell = 1.1 V
Q = [0.3 M]/[0.5 M]
Q = 0.6
From Nernst equation;
Ecell = E°cell - 0.0592/n log Q
Ecell = 1.1 - 0.0592/2 log (0.6)
Ecell = 1.1 - 0.0296 log (0.6)
Ecell = 1.11 V
the name of the acid present in milk
Answer:
lactic acidThe real acidity of milk is due to lactic acid. This is never found in milk when it is first drawn from the udder. It is produced by the action of the lactic acid organisms on the milk sugar. The so-called apparent acidity of milk is what gives fresh milk its acid reaction.
more reactive material can help to stop iron rusting true or false
Answer: Galvanising is a method of rust prevention. The iron or steel object is coated in a thin layer of zinc. This stops oxygen and water from reaching the metal underneath - but the zinc also acts as a sacrificial metal . Zinc is more reactive than iron, so it oxidises in preference to the iron object.
Explanation:
If aluminum has a mass of 22.3 g, how many liters of oxygen gas are required at STP?
Answer:
27.8
Explanation:
what do you understand by atomic theory
Answer:
Explanation:
All material substances are composed of minute particles or atoms of a comparatively small number of kinds and all the atoms of the same kind are uniform in size, weight, and other properties.
Hope this helped!!
Answer:
Atomic theory states that matter is composed of particles called atoms.
Explanation:
According to the theory, all types of matter can be divided into smaller parts, to the point it's indivisible.
An atom can be defined as the basic particle that composes a chemical element.
John Dalton's Atomic Theory:
All matter is made of atoms, which are indivisible.All atoms of a given element are identical in mass and properties.Compounds are combinations of two or more different types of atoms. A chemical reaction is a rearrangement of atoms.Dalton's theory was further modified by the discovery of sub-atomic particles, like the electrons, neutrons and protons.
7. Indicate if the following are correct or incorrect.
1s2
6s3
5f10
4d3
2d4
3p10
Answer:
1s2: correct.
6s3: incorrect because the subshell s can hold up to 2 electrons.
5f10: correct.
4d3: correct.
2d4: incorrect because the second energy level just has the s and p subshells.
3p10: incorrect because the p subshell can hold up to 6 electrons.
Explanation:
Hello there!
In this case, according to the attached file, which shows the correct orbitals and electrons, we can proceed as follows:
1s2: correct.
6s3: incorrect because the subshell s can hold up to 2 electrons.
5f10: correct.
4d3: correct.
2d4: incorrect because the second energy level just has the s and p subshells.
3p10: incorrect because the p subshell can hold up to 6 electrons.
Best regards!
Think about a single cell and its parts; for example, think about a cell inside the human body. Now, select an everyday object that could be used as a model for a cell and its parts. In words and/or pictures, describe your model and how it is like the cell.
Answer:
Mitochondria
Hydraulic Dams
Ribosomes
Small Shops
Nucleus
Town Hall
Endoplasmic Reticulum
Railroad Tracks
Golgi Bodies
Post Office
Cytoplasm
Clean Air and Water
Protein
Widget
Cell Membrane
Fence
Lysosomes
Scrap Yard
Nucleolus
Carpenter's Union
Vacoule
Warehouse
here is some ideas
What causes a blue block to appear blue in the sunlight?
Group of answer choices
the blue block reflects all blue light and absorbs all other light
the blue block absorbs blue light and reflects all other light
only blue light is refracted and all other light is absorbed into the block
only blue light transmits through the block and all other light is reflected
Answer:
sadgsddagd
Explanation:
how are you doing?