Answer:
High amount of energy is required to dissociate these bonds and hence water molecules have a higher boiling point than expected.
Explanation:
A mixture is prepared using 27.00 mL of a 0.0758 M weak base (pKa=4.594) , 27.00 mL of a 0.0553 M weak acid (pKa=3.235) and 1.00 mL of 1.25×10−4 M HIn and then diluting to 100.0 mL, where HIn is the protonated indicator. The absorbance measured at 550 nm in a 5.000 cm cell was 0.1102 . The molar absorptivity (????) values for HIn and its deprotonated form In− at 550 nm are 2.26×104 M−1cm−1 and 1.53×104 M−1cm−1 , respectively. What is the pH of the solution?
Answer:
pH = 4.164
Explanation:
The first process is to find the initial moles for the base (B) & the acid (HA)
i.e.
[tex]= \dfrac{27 mL \times 0.0758 \ moles \ \ of \ B}{1000 \ mL}[/tex]
[tex]=0.0020466[/tex]
[tex]\simeq 2.047\times 10^{-3} \ moles \ of \ B[/tex]
[tex]= \dfrac{27 mL \times 0.0553 \ moles \ \ of \ HA}{1000 \ mL}[/tex]
[tex]=0.0014931[/tex]
[tex]\simeq 1.493\times 10^{-3} \ moles \ of \ HA[/tex]
The acid with base reaction is expressed as;
HA + B → A⁻ + HB⁺
to 1.493 × 10⁻³ 2.047 × 10⁻³ - -
- 1.493 × 10⁻³ 1.493 × 10⁻³ 1.493 × 10⁻³ 1.493 × 10⁻³
0 5.54 × 10⁻⁴ 1.493 × 10⁻³ 1.493 × 10⁻³
From observation; both the acid & base weak
Given that:
The pKa for base = 4.594
The pKa for acid = 3.235
Recall that;
pKa = -log Ka
So; Ka = [tex]\mathbf{10^{-Ka}}[/tex]
By applying this:
For Base; Ka = [tex]10^{-4.594}[/tex] = 2.5468 × 10⁻⁵
For Acid: Ka = [tex]10^{ -3.235}[/tex] = 5.821 × 10⁻⁴
After the reaction; we have the base with its conjugate acid & conjugate base of acid; Thus, since the conjugate acid of the base possesses a higher value of K, it is likely it would be the one to define the pH of the solution.
By analyzing the system, we have:
HB⁺ + H₂O ↔ B + H₃O⁺
[tex]\dfrac{1.493\times 10^{-3}}{0.1 \ L}[/tex] [tex]\dfrac{5.54\times 10^{-4}}{0.1 \ L}[/tex]
to 0.01493 M 0.00554 M
- x x x
0.01493 - x 0.00554 - x x
Thus;
[tex]2.5468 \times 10^{-5} = \dfrac{(0.00554 -x)\times x}{(0.01493-x)}[/tex]
Using the common ion effect;
0.00554 - x [tex]\simeq[/tex] 0.00554 &
0.01493 - x [tex]\simeq[/tex] 0.01493
∴
[tex]x = \dfrac{2.5468 \times 10^{-5} \times 0.01493}{0.00554}[/tex]
x = [H₃O⁺] = 6.8635 × 10⁻⁵
∴
pH = -log(6.8635 × 10⁻⁵)
pH = 4.164
which is a way to express concentration of a solution? parts per billion moles molar mass force per square meter
Answer:
parts per billion
Explanation:
I took the quiz
Answer:
parts per billion
Explanation:
edge 2021
A 700 mL sample of gas at STP is compressed to 300 mL, and the
temperature is raised to 100.C. What is the new pressure of the gas in atm?
Answer:
P₂ = 3.19 atm
Explanation:
Given data:
Initial volume = 700 mL
Initial pressure = 1 atm
Initial temperature = 273K
Final temperature =100°C (100+273= 373 K)
Final volume = 300 mL
Final pressure = ?
Formula:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
Solution:
P₂ = P₁V₁ T₂/ T₁ V₂
P₂ = 1 atm × 700 mL × 373K / 273 K ×300 mL
P₂ = 261100 atm .mL. K /81900 K .mL
P₂ = 3.19 atm
28. After 3 substances are mixed, an odor emits
a. chemical change
b. physical change
c. thermal energy is used
a do
Answer:
a. chemical change
Explanation:
A chemical change can cause an odor, however a physical change cannot, and the use of thermal energy will only make an object colder, not give it an odor.
PLEASE HELP ME!!!!!!!!
Answer:
I think the answer is false
Which statement is true about copper and salt?
A sample of gas in a balloon has an initial temperature of 42 ∘C and a volume of 1.10×103 L . If the temperature changes to 86 ∘C , and there is no change of pressure or amount of gas, what is the new volume, V2, of the gas?
Answer:
1250L or 1.25*10^3
Explanation:
Use the combined gas law, [tex]\frac{P_{1} V_{1}}{T_{1} }[/tex]=[tex]\frac{P_{2}V_{2}}{T_{2} }[/tex]
Put the value for the temperature(in Kelvin) and volume, and you can just put 1 for P1 and P2 because it stays the same.
I'll assume that you meant to put 1.10*10^3L
PLEASE HELP WILL GIVE BRAINLIEST
Answer:
Coefficients represents no of moles while subscripts represent no of atoms.
Answer:
Coefficients came before formula . Example = 4CO means there are 4 molecules of carbonmonooxide.
Subscripts came after and below the formula . Example = Oxygen gas in which 2 is a subscript which means there are 2 atoms of Oxygen in 1 molecule of Oxygen i.e. oxygen gas
What is the definition of a chemical bond?
(A) a mutual repulsion between the nuclei and electrons in two different atoms
(B) a mutual attraction between the nuclei and electrons in two different atoms
(C) a mutual attraction between the nuclei and electrons in a single atom
(D) a mutual repulsion between the nuclei and electrons in a single atom
Answer:
B
Explanation:
bonding is a process of two different atoms sharing electrons for stability and these electrons are attracted by one atom losing it's electrons to another
What is the name of Bel on the periodic table
Answer:
Nobelium or Beryllium
What are chemical equations used to represent?
Answer:
A chemical equation is the symbolic representation of a chemical reaction. The reactants (the starting substances) are written on the left, and the products (the substances found in the chemical reaction) are written on the right.
Explanation:
pliz mark brainliest
Explanation:
chemical equations are used to represent a certain reaction between reactants to form products.
When the volume of a gas is
changed from 3.6 L to 15.5 L, the
temperature will change from
°C to 87°C.
Assume that the number of moles and the
pressure remain constant.
Be sure to notice that temperatures are
given in °C!
Answer:
-189.55°C
Explanation:
Given data:
Initial volume of gas = 3.6 L
Final volume of gas = 15.5 L
Initial temperature = ?
Final temperature = 87°C (87+273 = 360 K)
Solution:
The given problem will be solve through the Charles Law.
According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.
Mathematical expression:
V₁/T₁ = V₂/T₂
V₁ = Initial volume
T₁ = Initial temperature
V₂ = Final volume
T₂ = Final temperature
Now we will put the values in formula.
V₁/T₁ = V₂/T₂
T₁ = V₁T₂ /V₂
T₁ = 3.6 L × 360 K / 15.5 L
T₁ = 1296 L.K / 15.5 L
T₁ = 83.6 K
Kelvin to °C:
83.6 K - 273.15 = -189.55°C
Your skin is an important organ and has several functions. All of the functions below are performed by the skin EXCEPT
A)
makes vitamin D.
B
prevents-dehydration:
C)
maintains body temperature.
D)
works with bones to help you move.
Answer:D
Explanation:
Your skin makes vitamin D
Your skin prevents dehydration
And your skin maintains body temperature. So you are left with D
Answer:
The correct option is D.
works with bones to help you move
Explanation:
Skin is the outer layer of the body and it is the body's largest organ.
It protect the body from heat and other harmful substances.
It is comprises of three layers;
The Epidermis which is the outer layer.
The dermis which is a fibrous later that protect the Epidermis.
The subcutis is the subcutaneous layer that is beneath the dermis.
Function of the skin.
1. It's regulate body temperature
2. It's protect the body from heat and pathogenic entry.
3. It produces vitamin D
4. The skin allow sensations or feelings of touch, heat, and cold.
Therefore;
works with bones to help you move is wrong because it is the muscle that work with the bone.
Solve for x in the following equation?
v=w/x
Answer:
x = w/v
General Formulas and Concepts:
Pre-Algebra
Equality PropertiesExplanation:
Step 1: Define
v = w/x
Step 2: Solve for x
Multiply x on both sides: xv = wDivide v on both sides: x = w/vHELP 20 POINTS
What is the frequency of an Electromagnetic wave has with wavelength 2.94 x 10^-8 cm?
true or false A force can change the shape of an object.
Answer:
True
Explanation:
When a force acts on an object, the object may change shape by bending, stretching or compressing - or a combination of all three shape changes.
When naming covalent compound both the first and second element in the fomula always receive
a prefix to represent the number of each element present in the chemical formula.
Answer:
Yes.
Explanation:
Yes, both the first and second element in the formula of covalent compound always receive a prefix to represent the number of each element present in the formula in order to show the percentage or proportion of each element in the formula of covalent compound. Prefix refers to addition of word, letter, or number at the beginning of something so here number placed in front of element indicates the prefix.
tide occur in ocean but not in lake why
Answer:
Because while our lakes are Great, they're comparatively much smaller than oceans. And the gravitational pull isn't strong.
Which is a factor that keeps Earth in orbit around the Sun? the moon O the gravitational pull of the Sun the continuous motion of the universe Earth's changing speed and direction ctivity
Answer:
The Sun's gravitational pull keeps our planet orbiting the Sun. The motion of the Moon is affected by the gravity of the Sun AND the Earth. The Moon's gravity pulls on the Earth and makes the tides rise and fall every day. As the Moon passes over the ocean, there is a swell in the sea level.
Explanation:
The statement of factor that keeps Earth in orbit around the Sun is "the gravitational pull of the Sun."
What is the Sun and the Earth?The Sun is the primary star of our Solar System. The Earth revolves around our Sun, which really is a star. At a distance of around 93 million miles from the Sun, Earth is the third planet.
The fundamental force that governs the planets' orbits around the sun is gravity. While each planet does have its own gravity, which is determined by its size and speed of movement, orbit is determined by the gravity of the sun.
Our planet orbits the Sun due to it's gravitational pull. The Sun, as well as all of the planets and moons, are gravitationally bound together and circle all around solar system's centre of gravity.
The Sun's gravity is around 27.9 times that of Earth's, and it helps to govern the tides on Earth in a modest degree.
Hence the correct answer is the gravitational pull of the Sun.
Learn more about Sun and Earth here
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A radical is a reactive intermediate with a single ____________ electron, formed by ____________ of a covalent bond. Allylic radicals are stabilized by ____________ , making them ____________ stable than tertiary radicals. A compound that contains an especially weak bond that serves as a source of radicals is called a radical ____________ . Treatment of cyclohexene with N-bromosuccinimide in the presence of light leads to ____________ by ____________ intermediates.
1. A radical is a reactive intermediate with a single ____________ electron, formed by ____________ of a covalent bond.
1. A: Unpaired, and homolysis
2. Allylic radicals are stabilized by ____________ , making them ____________ stable than tertiary radicals.
2. A: Resonance, and more
3. A compound that contains an especially weak bond that serves as a source of radicals is called a radical ____________ .
3. A: Initiator
4. Treatment of cyclohexene with N-bromosuccinimide in the presence of light leads to ____________ by ____________ intermediates.
4. A: Allylic substitution by radical
What is another name for acetic acid? *
1. lemons, limes or oranges
2 .vinegar
3. vitamin C
An object with a
mass of 7 g and a
volume of 10 mL is
most likely what
substance?
Answer:
Ethanol
Explanation:
Given parameters:
Mass of the object = 7g
volume of the object = 10mL
Unknown:
The kind of substance it is = ?
Solution:
Since from the parameters, we can determine the density of the object. Density is an intensive property of substances.
So, we simply find the density and check a density table for the type of substance it is.
Density is the mass per unit volume.
Density = [tex]\frac{mass}{volume}[/tex]
Let us take the volume to cm³;
10mL = 10cm³
Density = [tex]\frac{7}{10}[/tex] = 0.7g/cm³
This is most likely ethanol
HELP DUE MONDAY!!
Don’t understand
Answer:
Concept: Chemical Analysis
You need to start by graphing the data and then analyzing it.We can see that the horse has a distance in meters of 980 at the end of the 10 seconds hence it is the fastest.The horse line has a linearly representation, while the alternate line has parabolic tendencies towards the end. The steeper line indicates a faster change in time or velocity which results in a greater distance traveled indicating that the horse is faster.*I have confidence you can graph that*Identify the double displacement reaction
2NH3+H2SO4
Answer:
......................
nh42so4
A typical home instant pot has an internal volume of 6.5 Liters. If the steam inside an instant pot with an internal pressure of 191.0 kPa and a temperature of 750.0 K was released into the atmosphere at 101.3 kPa and 298K, what volume with the steam occupy in the atmosphere?
HELPPPPPPPPP 35 POINTSSSSSS!!!!!
A metal is oxidized if it’s converted from its metallic form to make a compound, and it’s reduced if it’s converted back to its metallic form.
FILL IN THE BLANKS with either "reduce" or "oxidize"
Magnesium is able to copper, and copper is able to magnesium.
Zinc is able to magnesium, and magnesium is able to zinc.
Copper is able to zinc, and zinc is able to copper.
Answer:
oxidize
Explanation:
A log has a density of .8 g/cm³. What will happen to this log in freshwater, which has a density of 1.0 g/cm³?
It will sink.
It will float.
It will move deeper.
It will decrease in density.
Explanation:
Objects with a lower density will float while objects with a higher density will sink.
Since 0.8g/cm³ < 1.0g/cm³,
The log will float in freshwater.
Q. Which change has a negative entropy change of the system
A)Ice smell
B)Water heating up
C)Salt dissolving
D) none of these
Answer:
D) none of these
Explanation:
Assume that the total volume of a metal sample is the sum of the volume occupied by the metal ions making up the lattice and the (separate) volume occupied by the conduction electrons. The density and molar mass of the first metal are 911 kg/m3 and 27.7 g/mol, respectively; assume the radius of an ion is 97.3 pm. (a) What percent of the volume of a sample of this metal is occupied by its conduction electrons
Answer:
92.4%
Explanation:
The volume per cubic meter of sodium preoccupy by the sodium ions is
[tex]V_{Na} = n \times V[/tex]
where;
volume (V) of each Na atom = [tex]\dfrac{ 4}{3} \pi r^3[/tex]
Radius of each ion = 97.3 pm = 97.3 × 10⁻¹²
no.of atoms in the sample n = mass of the sample / ( molar mass / NA)
mass of the sample per cubic metre = 911 kg/m³
∴
[tex]V = \bigg [ \dfrac{4}{3} \pi r^3 \bigg ] \bigg [\dfrac{MN_A}{m} \bigg ][/tex]
[tex]V = \bigg [ \dfrac{4}{3} \pi (97.3 \times 10^{-12} )^3 \bigg ] \bigg [\dfrac{ (911 kg/m^3 (m^3))(6.023\times 10^{23})}{27.7 \times10^{-3}\ kg/mol } \bigg ][/tex]
V = 0.07643 m³
The fraction of available conduction electrons are;
= (1 - V)
= 1 - 0.07643
= 0.92357
≅ 92.4%
why do chemist synthesize polymers in the lab?
The reason why chemists synthesize polymers in the lab is;
because of the need to perform and observe the results of a variety of synthesized polymer reactions and to predict when a reaction will happen.
Polymers are simply defined as a substance or material made up of long repeating chemical chains of molecules.
Now, polymer synthesis is simply called polymerization and it is the process by which smaller molecules called monomers undergo covalent bonding to form a longer polymer chain.
Now, from the definition above, the reason why chemists synthesize polymers in the lab is because of the need to perform and observe the results of a variety of synthesized polymer reactions and to predict when a reaction will happen.
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