Answer:
pH = 3.3
Explanation:
Buffer solutions minimize changes in pH when quantities of acid or base are added into the mix. The typical buffer composition is a weak electrolyte (wk acid or weak base) plus the salt of the weak electrolyte. On addition of acid or base to the buffer solution, the solution chemistry functions to remove the acid or base by reacting with the components of the buffer to shift the equilibrium of the weak electrolyte left or right to remove the excess hydronium ions or hydroxide ions is a way that results in very little change in pH of the system. One should note that buffer solutions do not prevent changes in pH but minimize changes in pH. If enough acid or base is added the buffer chemistry can be destroyed.
In this problem, the weak electrolyte is HNO₂(aq) and the salt is KNO₂(aq). In equation, the buffer solution is 0.55M HNO₂ ⇄ H⁺ + 0.75M KNO₂⁻ . The potassium ion is a spectator ion and does not enter into determination of the pH of the solution. The object is to determine the hydronium ion concentration (H⁺) and apply to the expression pH = -log[H⁺].
Solution using the I.C.E. table:
HNO₂ ⇄ H⁺ + KNO₂⁻
C(i) 0.55M 0M 0.75M
ΔC -x +x +x
C(eq) 0.55M - x x 0.75M + x b/c [HNO₂] / Ka > 100, the x can be
dropped giving ...
≅0.55M x ≅0.75M
Ka = [H⁺][NO₂⁻]/[HNO₂] => [H⁺] = Ka · [HNO₂]/[NO₂⁻]
=> [H⁺] = 6.80x010⁻⁴(0.55) / (0.75) = 4.99 x 10⁻⁴M
pH = -log[H⁺] = -log(4.99 x 10⁻⁴) -(-3.3) = 3.3
Solution using the Henderson-Hasselbalch Equation:
pH = pKa + log[Base]/[Acid] = -log(Ka) + log[Base]/[Acid]
= -log(6.8 x 10⁻⁴) + log[(0.75M)/(0.55M)]
= -(-3.17) + 0.14 = 3.17 + 0.14 = 3.31 ≅ 3.3
What is the differences between solids liquids and gases on a molecular level apes.
Which sentence from the article BEST describes HOW fireworks produce colors in the sky?
(A)
It needs an oxidizer, a fuel and a chemical mixture to produce the color.
(B)
Over the years, scientists have staged various chemical reactions to produce fireworks of different
colors.
(C)
The color of that light depends on what chemical elements are present.
(D)
When the casing explodes, pellets containing the chemical color mixtures fly out.
Fireworks need an oxidizer, fuel, and a chemical mixture to produce the colour in the sky. Therefore, option (A) is correct.
How do colours come from firecrackers?The chemicals which are used in crackers are the main reason for the colours in the sky. The colours in the fireworks come from different compounds which are the binder and the colourant. The colourant chemicals provide the colours in the firework while the binder is the agent that binds the fuel and is responsible to burn up the colourant in the firework.
The colourants in the firecrackers can be generated with the use of various metallic salts. These salts can be defined as iconic compounds which possess an anion or an acid and a cation or a base. The metal salts are responsible for generating intense colours when they are burned.
For example, if use calcium salts in the firework will produce an orange colour, and copper salts will produce a bright blue colour.
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Explain how the heat and phase changes affects the environment? Give examples.
(5-7 sentences)
What is carbon? What does it do?
How are polypeptides and proteins similar?
A. They are both made of amino acids.
B. They are both polysaccharides.
O C. They are both nucleic acids.
D. They are both made of carbohydrates.
Answer is A
Answer:
The answer is A.
Explanation:
They are both made of amino acids.
Which product in the reaction forms a precipitate? PbSO4 MgCl2 PbMg no precipitate formed
MgCl2 product in the reaction forms a precipitate because it is solid an insoluble salt and not dissolve in solution and precipitate on the bottom surface of the solution.
What is precipitation reaction?The chemical reaction in which two ionic bond combine to form an insoluble salt in a aqueous solution is called precipitation reaction.
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Use the periodic table to identify the number of core electrons and the number of valence electrons in each case below.
Can you please add a picture of the case??
If Temperature 25 C and volume is 117.5 cm³. Explain volume temperature relationship using Charles’s law.
(No links or else I'll report.
Don't answer if u dont know.)
Thank You.
Explanation:
According to Charles law : V/T=k (constant).
the volume temperature relationship will be
V/T = 117.5/25 = 4.7
hope this helps you.
The structure of the periodic table is based on the distribution of
in each element. The elements are arranged in horizontal and vertical
Answer:
B- electrons, A- periods, B- groups
Explanation:
when the corporation issuing the bonds has the right to redeem the bonds prior to the maturity, the bonds are
Answer:
Callable or redeemable bonds
Explanation:
"..are bonds that can be redeemed or paid off by the issuer prior to the bonds' maturity date."
A gas occupies a volume of 120 mL at 700 mm Hg. What will happen to the volume of the gas if the pressure is changed to 1500 mm Hg at constant temperature
Answer:
56 mLExplanation:
The new volume can be found by using the formula for Boyle's law which is
[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]
where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
From the question we have
[tex]V_2 = \frac{700 \times 120}{1500} = \frac{84000}{1500} = \frac{840}{15} \\ = 56[/tex]
We have the final answer as
56 mLHope this helps you
An endothermic process may be spontaneous if ______. Multiple choice question. the endothermic process results in a precipitation of a crystalline solid from a liquid solution the endothermic process converts a gas reactant into a liquid or solid product the product particles have more freedom of motion than the reactant particles the product particles have less freedom of motion than the reactant particles
An endothermic process may be spontaneous if: C. the product particles have more freedom of motion than the reactant particles.
An endothermic reaction can be defined as a type of chemical reaction in which heat energy is absorbed from the environment.
Generally, heat energy is absorbed in a chemical reaction when the energy of the products is greater (more) than the energy of the reactants and this is referred to as an endothermic reaction.
Similarly, an endothermic process may be spontaneous when the product particles have more freedom of motion than the reactant particles.
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what type of bacteria use the enzyme nitrate reductase to metabolize nitrogen oxides and transform them back to nitrogen gas?
Denitrifying Bacteria such as Pseudomonas aeruginosa is the type of bacteria that use enzyme nitrate reductase to metabolise nitrogen oxides to nitrogen gas.
Denitrification is the process whereby nitrites or nitrogen oxides is converted to nitrogen gas by a denitrifying Bacteria such as Pseudomonas.
Pseudomonas aeruginosa uses enzyme nitrate reductase to reduce nitrate to nitrite.
Then nitrite is then converted back to nitrogen gas.
Therefore, Pseudomonas aeruginosa is a type of bacteria that uses enzyme nitrate reductase.
Which two factors will improve the efficiency of an inclined plane?
the answer is using rollers in conjunction with inclined plane.
Is krypton a good or poor conductor of electricity? Why? I
Answer:
No it is not a good conductor
Explanation:
Krypton is classified as a gas and nonmetal. Like many nonmetals and gases, krypton is an insulator, so it is a relatively poor conductor of heat and electricity.
State the term used for the light that is transmitted when complex ions absorb wavelengths of visible light. Give the answer using two words only (and be careful with spelling).
Answer:
complementary colour
Explanation:
The complementary colors are used for the light that is transmitted when complex ions absorb wavelength of visible light.
What is complementary colors?
Complementary colors are color pairs that cancel each other whenever combined and mixed, resulting in a grayscale color either white or black. They offer the most contrast for the those two hues when put adjacent to each other. Colors that are complementary are sometimes known as "opposite colors."
What is light?Light, often known as visible light, is electromagnetic radiation that falls within the region of the electromagnetic spectrum which the human eye can perceive.
Therefore, the complementary colors are used for the light that is transmitted when complex ions absorb wavelength of visible light.
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- A beam of electrons has.....
(A) Wave properties.
(B) Particle properties.
(C) Both of these
(D) Neither of these
Answer:
(C) Both of these
Explanation:
A beam of electrons has both of these Wave properties and Particle properties.
How do erosions affect land forms?
Erosion is the only cause of land form changes.
Land forms can be created by erosion.
Erosion can prevent land forms from being built.
Land forms can only be created through erosions.
Answer:
the anwser is landforms can be created by erosion
Explanation:
15
The diagram below shows a landscape
Upper atmosphere
Ocean
Where in the diagram would the air pressure be
the greatest
Answer:
No diagram no help
Explanation:
The half-life of a radioactive substance is 15 days. After 10 days a sample of the substance has been reduced to a mass of 4 mg. A. What was the inital mass (in mg) of the sample? B. Using your answer from above, after how many days will there only be 0. 3 mg of substance left?.
A. The initial mass of the sample is 6.35
B. The time taken for 0.3 mg of the sample to remain is 66 days
A. Determination of the initial mass of the sample
We'll begin by calculating the number of half-lives that has elapsedHalf-life (t½) = 15 days
Time (t) = 10 days
Number of half-lives (n) =?n = t / t½
n = 10 / 15
n = ⅔Finally, we shall determine the initial mass of the sample.Number of half-lives (n) = ⅔
Amount remaining (N) = 4 mg
Initial amount (N₀) =?[tex]N_0 = N \times {2}^{n} \\ N_0 = 4 \times {2}^{2 \div 3} \\ N_0 = 6.35 \: mg[/tex]
Therefore, the initial mass of the sample is 6.35 mg
B. Determination of the time
We'll begin by calculating the number of half-lives that has elapsedAmount remaining (N) = 0.3 mg
Initial amount (N₀) = 6.35 mg
Number of half-lives (n) =?[tex]{2}^{n} = \frac{N_0}{N} \\ \\ {2}^{n} = \frac{6.35}{0.3} \\ \\ {2}^{n} = 21.167 \\ take \: the \: log \: of \: both \: side \\ log \: {2}^{n} = log \: 21.167 \\ nlog2 = log \: 21.167 \\ divide \: both \: side \: by \: log2 \\ \\ n = \frac{log \: 21.167}{log2} \\ \\ n = 4.4[/tex]
Finally, we shall determine the timeNumber of half-lives (n) = 4.4
Half-life (t½) = 15 days
Time(t) =?t = n × t½
t = 4.4 × 15
t = 66 daysTherefore, it will take 66 days for 0.3 mg of the sample to remain.
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4. One gram of of ............... contains one type of atoms. a. iron b. ammonia c. hydrogen chloride d. water
Answer: hydrogen chloride.
Explanation:
Shanika is an engineer at an amusement park who is experimenting with changes to the setup for a magnetic roller coaster ride. In one ride, there are two identical roller coaster cars (orange and green) that start on opposite sides of a large magnet located at the center of a station. Shanika wants to get the largest increase in potential energy she can by moving one car one space to the left or the right. Shanika can move the orange car to point A or point B, or she can move the green car to point C or point D. Which movement should she make? Why will that movement result in the largest increase in potential energy? Describe the magnetic force that will act on the roller coaster car she moves. What should I do for the Green cart?
The orientation of the poles of the magnet on the cars and the large
magnet are like poles.
The correct responses are;
First question
Move the orange car from A to B Move the green car from D to CSecond question:
The reason is reducing the distance increases the magnetic field strengthThird question:
It pushes the cars away in the opposite direction.
Fourth question:
Place the green car at point C to get the largest potential energyReasons:
Potential energy is the energy an object has due to its location.
Energy is a product of force and distance, and therefore, if the force,
experienced by the object increase, the potential energy of the object
increases.
The strength of a magnetic field, B, is given by the formula;
[tex]\displaystyle B = \frac{\mu_0 \cdot I}{2 \cdot \pi \cdot d}[/tex]
Where;
B = The magnetic field strength
I = Current
d = The distance from the source of the magnet
μ₀ = The permeability of free space = 4·π × 10⁻⁷ T m/A
Therefore, the strength of the magnet is higher closer to the source.
First question
In a magnet, like poles push each other back, and given that the poles of the magnet adjacent to each other are like poles, to get the largest increase in she should move the cars towards the large magnet.
Move the orange car from A to B Move the green car from D to CSecond question:
The reason why the movement will result in the largest increase in potential energy is because like polls repel each other and the strength of a magnetic field increases closer to the magnet
Third question:
The magnetic force that will act on the roller coaster car moved towards the large magnet, pushes the car in the opposite direction.
Fourth question:
The green cart should be moved from point D to point C to get the largest potential energy
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A student dissolved some crystals of a salt in water.
The student added sodium hydroxide solution to the salt solution
The student added sodium hydroxide until it was in excess
Describe what the student would see if the salt contained calcium ions
Under Normal Conditions no reaction will be seen between Calcium ions (Ca⁺), NaCl (salt solution) and NaOH(sodium hydroxide).
What is a double replacement reaction ?In a double replacement reaction , the compounds present switch cation and anion to form new compounds.
But here in NaOH(sodium hydroxide) and NaCl (salt solution) the cation sodium ion Na⁺, of both the compounds is same so the end result will be same .
There will be no net reaction .
But if excess Sodium Hydroxide is added to the solution , we will see precipitate of NaCl , salt forming.
If Salt contained Ca⁺ ions , firstly NaCl will only combine with Ca⁺ ions in special conditions as Na⁺ ions are more reactive than Ca⁺ ions.
On addition of NaOH we would observe no change in normal conditions due to above stated reason .
In special conditions following reaction takes place ,in normal condition the reaction follows reverse direction.
Ca + 2 NaOH ← Ca(OH)₂ + 2 Na
Hence under Normal Conditions no reaction will be seen between Calcium ions , NaCl (salt solution) and NaOH(sodium hydroxide).
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What defines an element?
Explanation:
each of more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter. Each element is distinguished by its atomic number, i.e. the number of protons in the nuclei of its atoms.
Question 2
20 pts
What types of elements make up salt and what type of compound is it?
nonmetals only and covalent
metals only and ionic
metals and nonmetals and ionic
What is atomic mass? the mass of the atom based on the mass of an atom of hydrogen-1 the mass of an atom based on the mass of an atom of carbon-12 the mass of the atom based on the mass of an atom of oxygen-16 the mass of an atom based on the number of electrons
Answer:
The mass of an atom based on the mass of an atom of carbon-12
Explanation:
An ameba absorbs oxygen from its environment and releases carbon dioxide into its environment. This process is known as
Answer:
Respiratory gas exchange
Explanation:
what happened if you poured lava on snow
Answer:
This is what could happen:
Explanation:
When lava meets ice, the resulting mess can cause flooding, destroy valuable resources and even produce explosions.
Answer: When lava meets ice, it neither explodes nor tunnels through; rather, it forms strange-looking bubbles.
Explanation:
What is the molarity of Na+ ions in a 0.02M sodium phosphate solution?
Answer:
.06 M NA+
Explanation:
You go from (.02M Na3PO4 / 1) x (3 mole Na+ / 1 mole Na3PO4) = .06 M Na+
What mass of water absorbs 6700 J of heat to raise the temperature from 283K to 318K?
Answer:
you did not give the specific heat like formula like it takes 1kj to raise 28grams of water by 10 grams