Answer:
[H₂A] = 0.2M
[HA⁻] = 0.8M
Explanation:
A compound with 2 ionizable groups has as equilbriums:
H₂A ⇄ HA⁻ + H⁺ ⇄ A²⁻ + H⁺
A pH of 6.8 is near to the first equilibrium:
H₂A ⇄ HA⁻ + H pKa = 6.2
To determine concentrations of the acid H₂A and conjugate base HA⁻ we use H-H equation:
pH = pKA + log [HA⁻] / [H₂A]
6.8 = 6.2 + log [HA⁻] / [H₂A]
0.6 = log [HA⁻] / [H₂A]
3.981 = [HA⁻] / [H₂A] (1)
As concentration of the buffer is 1.0M:
1M = [HA⁻] + [H₂A] (2)
Replacing (2) in (1):
3.981 = 1- [H₂A] / [H₂A]
3.981[H₂A] = 1 - [H₂A]
4.981 [H₂A] = 1
[H₂A] = 0.2M
And [HA] = 1M - 0.2M = 0.8M
b. What is the mass of a piece of wood that has a volume of
25.3cm® and a density of 0.75g/cm?
Answer:
Explanation:
[tex]\frac{mass}{volume} =density\\mass=volume \times density=25.3 \times 0.75=18.975 ~gm[/tex]
The emission spectrum for an element is? Select all that apply
Answer: You didn't give anything to select, however, the emission spectrum of a chemical element is frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state.
Calculate the mass of one molecule of propane (C_3H_8)
1. It is lab day in science class! Mr Benson is out in the hall talking with other teachers when the bell
rings. Justin decides to go ahead and get started with the lab. He begins weighing chemicals, touching
ihem with his hands. He gets an itch in his nose and rubs it with his hand.
Question part in the given data is missing, however the missing part is as follows:
What safety rules were violated?
Answer:
The correct answer would be:
-Never work in the lab without teacher or adult present
-Keep chemicals away from hands and face.
-Do not touch lab supplies without permission
Explanation:
According to the lab safety and precaution rules one should follow the lab rules strictly to avoid any risk and mishap. These rules include, the chemical management, lab safety equipment, and many other rules including don not work in absence of teacher or the adult.
One should avoid touching chemical and equipment without permission of teacher and never touch chemicals with bare hand and not to touch chemical and keeps it from face.
All scientific discoveries are made in a
laboratory.
True
False
pls helppp
Answer:
i would say false.
Explanation:
some discoveries are made as people continue exploring the world...........they are just prooved in the laboratory, while there are other which are still made in the lab and are also examined there.
Point P(-4, 0) lies on the directed line segment AE. The endpoints are A(2,-6)
and E(x, y). What are the coordinates of point E such that AP is 3/4 of the
distance from A to E?
Answer: (10,-14) I think
Explanation:
What is the most important laboratory procedure to follow before leaving the lab area? A. Record all of your results in your lab notebook. B. Wash your hands thoroughly with soap and water. C. Make sure that rulers and thermometers are put away. D. Ask the teacher for permission to leave.
Answer:
Wash your hands thouroughly with soap and water
Explanation:
Guessing. Hope I get it right for a brainly
Answer:
B C E
Explanation:
are all correct
what do you think ionization means?
Which elements are present in ammonia and calculate its mass
Answer:
nitrogen and hydrogen
Its molecular mass is 17g
Explanation:
Ammonia = NH3
nitrogen= 14g
hydrogen= 1g × 3 =3
14+3=17
How much energy is passed to the next trophic level in the food chain?
Answer:
10%
Explanation:
Out of the original layer, only ten percent is transferred to the next
What is Thermal Energy?
What name is given to a reaction that takes in energy from the surroundings?
Answer:
Endothermic reaction
Explanation:
Endothermic reactions take in energy from the surroundings.
Energy is a reactant in endothermic reactions, and the temperature of the surroundings will decrease because it took in energy.
the particles in water have less mobility than the particles in oxygen. Which statement best explains this observation? Water is always colder than oxygen. Water has a lower density than oxygen. Water particles have a greater kinetic energy. Water particles have strong intermolecular forces.
Answer:
Water particles have strong intermolecular forces.
Explanation:
Water molecules are affected by attraction and repulsion and that causes the water to have strong forces and intermolecular strength to be strong.
Water particles have strong intermolecular forces.
What are intramolecular forces?Intramolecular forces are the forces that keep atoms together inside a molecule. Intermolecular forces are forces that exist among molecules. determine intermolecular appeal between H-Cl molecules and intramolecular attraction within H-Cl molecules.
What are the strongest intramolecular forces?The most powerful intermolecular forces are dipole-dipole interactions. A dipole-dipole pressure is while the high-quality aspect of a polar molecule draws the bad facet of every other polar molecule.
Learn more about intermolecular forces here: https://brainly.com/question/25920008
#SPJ2
Neutrons are about the same size as....
Answer:
proton
Explanation:
if it was not an isotope..
In two or more complete sentences explain how to balance the chemical equation, KClO3 ⟶ KCl + O2 and include all steps. Write your response in the essay box below.
Answer:
2KClO3 -------> 2KCl + 3O2
Explanation:
First, in balancing a chemical reaction such as the one given in the question, you should understand that for an equation to be balanced, the number of atoms and ions on both sides of the equation that is the right and left side must be equal. This follows the law of conservation of mass which tells us that matter can neither be created nor destroyed but can be changed into another form.
Next is to begin balancing the equation by identifying and writing down the substances given:
KCl03 ---------> KCl + O2
Next is to count he number of the individual atoms on each side and find out if they are the same on both sides and if not you must follow the next step.
Add a corresponding number and use it to multiply the atoms involved
KClO3 ---------> KCl + O2
Oxygen is 3 on the left side and two on the other side, so we multiply the left hand side by 2 and the right hand side by 3
2KClO3 -----> KCl + 3O2
The potassium and Chlorine are no longer balanced, so you multiply the right had=nd side of KCl by 2.
2KClO3 -----> 2KCl + 3O2
The reactionis herefore balanced as both sides have equal number of atoms and ions.
During freezing, a substance? -loses chemical energy -loses thermal energy -gains thermal energy -gains chemical energy
The process of melting a crystalline solid can be
reversed if the liquid is cooled. The change from the liquid state
to the solid state is called freezing. As the liquid cools, it loses
thermal energy. As a result, its particles slow down and come
closer together. Attractive forces begin to trap particles and the
crystals of a solid begin to form.
"The total kinetic energy of all the particles in a sample of
matter is called thermal energy. Thermal energy, an extensive
property, depends on the number of particles in a substance as
well as the amount of energy each particle has. If either the
number of particles or the amount of energy in each particle
changes, the thermal energy of the sample changes. With identically sized
samples, the warmer substance has a greater thermal energy."
is water a compound?
Answer:
Yes, actually it is a compound.
Explanation:
There are important differences between the properties of a mixture and a compound. In this table, the column Mixture refers to the gasses hydrogen and oxygen, and the column named Compound refers to water.
What structures and materials are found in all cells?
Answer: the plasma membrane, the cytoplasm, ribosomes, and genetic material.
hope this helped
In a desert ecosystem, coyotes and rattlesnakes both eat the same type of mouse as a primary part of their diets. Recently, coyotes have been hunted and killed by people, decreasing the overall coyote population.
Answer:
there primary food source will still be the same
Explanation:
they will still ear mice but coyotesmay eat Humans if they are close because once they see humans they think they will be killed its there protectiong
Answer:
D. It will increase because coyotes are the competition.
Explanation:
Because Competition is When 2 organisms fight for the same thing, and sense rattlesnakes are the other competition they will increase because coyotes are being killed.
What is a sediment and how it is formed?
Answer:
Sedimentary rocks are formed when sediment is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension. This sediment is often formed when weathering and erosion break down a rock into loose material in a source area.
Im not sure if this answers your question but here!
Sedimentary rocks are one of three main types of rocks, along with igneous and metamorphic. They are formed on or near the Earth’s surface from the compression of ocean sediments or other processes.
The allowable concentration level of vinyl chloride, C2H3Cl, in the atmosphere in a chemical plant is 2.0 x 10-6 g/L. a. How many moles of vinyl chloride in each liter does this represent?
Answer:
3.2x10⁻⁸ moles of vinyl chloride per liter
Explanation:
The concentration of C₂H₃Cl is 2.0x10⁻⁶g/L. To find moles per liter we need to convert this mass to moles using molar mass of vinyl chloride:
Molar mass C₂H₃Cl:
2C = 2*12g/mol = 24
3H = 3*1g/mol = 3
Cl = 1*35g/mol = 35
Molar mass = 35g/mol + 3g/mol + 24g/mol = 62g/mol
2.0x10⁻⁶g * (1mol / 62g) =
3.2x10⁻⁸ moles of vinyl chloride per literReaction coordinates represent: A. The balanced equation for a chemical reaction. B. The change in pH for a chemical reaction. C. The potential energy change for a chemical reaction. D. None of the above
Answer:
C. The potential energy change for a chemical reaction.
Explanation:
The reaction coordinate q illustrates, graphically, the energy changes during exothermic and endothermic reactions. This graphical representation of the energy changes in the course of a chemical reaction is known as reaction coordinates. A reaction coordinate is a graphical sequence of steps by which the reaction progresses from reactants through activated complexes to products. Reaction coordinates explain how far a reaction has proceeded towards the products or from the reactants.
From the images attached below, we can see the reaction coordinates in the reaction profiles.
tell me answer........... fast
Answer:
45
Explanation:
1+4x1=5
2+5x2=12
3+6x3=21
5+8x5=45
If you have 45.6mL of a liquid and its
mass is measured at 46.83g, what is its
density? What liquid is it?
If 24.1 g of sodium hydroxide react with 22.0 g of hydrochloric acid to form 35.3g
of table salt, how much water was formed? *
Answer:
10.85 g of H2O.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
NaOH + HCl —> NaCl + H2O
Next, we shall determine the mass of NaOH that reacted and the mass of H2O produced from the balanced equation.
These can be obtained as illustrated below:
Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol
Mass of NaOH from the balanced equation = 1 × 40 = 40 g
Molar mass of H2O = (2×1) + 16 = 2 + 16 = 18 g/mol
Mass of H2O from the balanced equation = 1 × 18 = 18 g
Summary:
From the balanced equation above,
40 g of NaOH reacted to produce 18 g of H2O.
Finally, we shall determine the mass of water, H2O produced from the reaction as follow:
From the balanced equation above,
40 g of NaOH reacted to produce 18 g of H2O.
Therefore, 24.1 g of NaOH will react to produce = (24.1 × 18)/40 = 10.85 g of H2O.
Therefore, 10.85 g of H2O were produced from the reaction.
How many elements are represented in the formula CaCO3
Answer:
3
Explanation:
calcium (Ca)
carbon(C)
oxygen(O)
hope u like it ❤️❤️
For any question comment me
Answer:
3 different elements, 6 total in the Calcium Carbonate molecule
Explanation:
Ca=Calcium
C=Carbon
O=Oxygen (* 3)
What food is made up of gelatin and why does it have protein in it?
Answer:
gummy´s and it can be lofat gummy´s
Explanation:
What are octet and duplet rules ?
Answer:
DUPLET RULE: The tendency of an atom to acquire an outer most shell of two electrons is called duplet rule. OCTET RULE: The tendency of an atom to acquire an outermost shell of eight electrons is called the octet rule.
This type of cell contains a nucleus and organelles that are surrounded by membranes. A.prokaryotic B.eukaryotic C.unicellular D.bacteria
Answer:
b is the correct answer
1. _____ There are tracks from three different animals in the rock.
2. _____ One animal was chasing another animal.
3 _____. Two different animals died in this spot.
4. _____ When the animals walked here the ground was wet.
5. _____ One of the animals that died here had bony plates.
6. _____ One of the animals that died here had sharp teeth.
7. _____ The animal that had sharp teeth ate meat.
A. Observation
B. Inference
Answer:
1.Observation
2. Inference
3. Observation
4. Inference
5. Observation
6. Observation
7. Inference.