Answer:If we dissolve NaF in water, we get the following equilibrium:
text{F}^-(aq)+text{H}_2text{O}(l) rightleftarrows text{HF}(aq)+text{OH}^-(aq)
The pH of the resulting solution can be determined if the K_b of the fluoride ion is known.
20.0 g of sodium fluoride is dissolve in enough water to make 500.0 mL of solution. Calculate the pH of the solution. The K_b of the fluoride ion is 1.4 × 10 −11 .
Step 1: List the known values and plan the problem.
Known
mass NaF = 20.0 g
molar mass NaF = 41.99 g/mol
volume solution = 0.500 L
K_b of F – = 1.4 × 10 −11
Unknown
pH of solution = ?
The molarity of the F − solution can be calculated from the mass, molar mass, and solution volume. Since NaF completely dissociates, the molarity of the NaF is equal to the molarity of the F − ion. An ICE Table (below) can be used to calculate the concentration of OH − produced and then the pH of the solution.
Explanation:
Answer:
not sure if this is 100% correct but this is what i got first question: molarity=mol/L 5g*1mol/58.44g=5/58.44 =0.085558mol 4.8m=0.085558/L L=0.0178
jiujuan avatar
second question: pH = - log [H3O+] pH= -log [4.6*10^-9] = 8.33724216
Explanation:
how many moles are in 37.5 g nitrogen
How is chemical equilibrium achieved?
Question 15 options:
When the concentrations of reactants and products are constantly changing.
When the concentrations of reactants and products are constant.
When the concentrations favor the reactants.
When the concentrations favor the products.
Answer:
Explanation:
Equilibrium is achieved in a chemical reaction when there is a steady state with no change in concentrations.
So the answer is "When the concentrations of reactants and products are constant."
Which of the chemicals in the following chemical reaction is the acid?
HCO3- + H20 -->CO3^2- +H30+
A.) HCO3-
B.) co3²-
C.) H30+
D.) H20
A) HCO3- , carbonic acic
what is the ratio of calcium and oxygen?
Answer:
5:2
//answer was too short //
Answer:
The ratio by mass for calcium and oxygen in a calcium oxide is given by 5:2
hope it helps
a raindrop has a mass of 0.050g. how many moles of water does a raindrop contain
Answer:
The raindrops of mass 0.050g has 0.0028 moles of water
LOOK im girl and i like this girl and I KNOW " she is gay" NO IM PAN so ya but do i ask out this girl?
Answer:
Do it if you feel like its your chance! Good luck!
Explanation:
An ionic compound is what ?
Answer:
In chemistry, an ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding
Answer:
An Ionic compounds are compounds consisting of ions also held together by the attractive forces among the oppositely charged ions.
Explanation:
For example :
NaHCO3, sodium bicarbonate (baking soda; used in cooking)
NaCl, sodium chloride (common/ordinary salt)
A birthday balloon is filled with 6.4 L of Helium. The pressure changes to 0.87 atm and the balloon expands to occupy a volume of 20.5 L. What was the initial pressure exerted on the balloon in psi?
PLS HELP WITH WORK!!
Answer:
3.97 psiExplanation:
The new pressure can be found by using the formula for Boyle's law which is
[tex]P_1V_1 = P_2V_2[/tex]
Since we're finding the new pressure
[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]
We have
[tex]P_2 = \frac{6.4 \times 0.87}{20.5} = \frac{5.568}{20.5} \\ = 0.2716.... \\ \\ = 0.27 \: \: \: atm[/tex]
But
1 atm = 14.7 psi
Then 0.27 atm =
[tex] \frac{14.7 \times 0.27}{1} = 3.969 \\ [/tex]
We have the final answer as
3.97 psiHope this helps you
Answer:
3.97 psi
Explanation:
Why does increasing the temperature of water increase the rate of chemical reaction in the graph
Answer:
Explanation:
Increasing the temperature increases reaction rates because of the disproportionately large increase in the number of high energy collisions.
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Large objects that form dense gravity wells in space A. Galaxies B. Star C. Nebulae D. Black holes.
Answer:
D. Black Holes
Explanation:
Black holes are large objects that form dense gravity wells in space. Their gravitational pull is so strong that even light cannot escape it.
Large objects that form dense gravity wells in space are stars and blackholes. The correct answer is option B and D.
Gravity: it is referred to as force of attraction experienced by a body having mass, towards the center of Earth.
Both stars and black holes are massive objects that exert a significant gravitational force due to their mass. They create what is known as a gravity well, which is a region of space where the gravitational pull is strong enough to affect the motion of nearby objects.
On the other hand, Galaxies and nebulae, are not individual objects with sufficient mass to form dense gravity wells. Galaxies consist of a collection of stars, gas, and dust, and while they have a collective gravitational influence, it is not concentrated in a single massive object like a star or black hole. Whereas, Nebulae are interstellar clouds of gas and dust, which do not possess the mass required to create significant gravity wells.
Therefore, the correct options from the given list that form dense gravity wells in space are B. Star and D. Black holes.
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At what temperature does a gas at 1.00 atm and 20 degree Celsius have a pressure of 4.00 atm.
Please help thanks.
Answer:
P1 =4 atm
T1= 20°C
P2=1 atm
T2=?
According to Gay-Lussac's Law or Third Gas Law,
P1T2=P2T1
4×T2=1×20
T2= 20/4
T2= 5°C
Answer At 5°C temperature does a gas at 1.00 atm !
between 316 m/s and 1162 m/s, which has the faster speed
Answer:
1162m/s is the faster speed
Explanation:
The speed is a physical property defined as the distance travelled of an object in determined amount of time.
A speed of 316m/s means the object is travelling 316 meters per second transcurred.
In the same way, the speed of 1162m/s means the object is travelling 1162m per second.
As the second object is travelling more distance per second than the first,
1162m/s is the faster speedHow long does it take for fruit flies to develop from embryos to adults?
Faster-moving water can carry a greater load.
true or false
Answer:
That is false
Explanation:
Just because it moves faster doesn't mean that it can carry and bigger load.
Answer:
False
Explanation:
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What term describes the temperature at which a substance can change state from a liquid to a gas?
A. Boiling point
B. Melting point
C. Freezing point
D. Specific heat
Option A. Boiling point.
Explanation:
When you heat the water, the water gets converts into gaseous form.
As you know that water is in liquid form. So, when you heat the water, the water molecules absorbs the heat and get dispersed from one another molecules. i.e., molecules go far from the other molecules as they absorbed heat.
The term describes the temperature at which a substance can change state from a liquid to a gas, is boiling point. Therefore, option A is correct.
What is boiling point ?The temperature at which a liquid's vapor pressure equals the pressure around it and the liquid transforms into a vapor is known as the boiling point of a substance. A liquid's boiling point varies depending on the atmospheric pressure in the area.
Boiling point and saturation temperature are synonyms. Sometimes the measurement's pressure serves as a definition for the boiling point. The International Union of Pure and Applied Chemistry was founded in 1982.
The boiling point of a sample can be calculated using a number of techniques, such as distillation, reflux, and a Thiele tube. The simplest approach makes use of a Thiele tube and has the benefit of requiring less than 0.5mL of substance.
Thus, option A is correct.
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what happens to the wavelength as frequency increases
Explanation:
The higher the wavelength, the lower its frequency and energy
Answer:
As frequency increases wavelength decreases in size
Explanation:
The wavelength of the wave is inversely proportional to the frequency of the wave as the speed of the wave remains constant.
v = fλ ( v - speed, f - frequency, -wavelength)
[tex]\frac{v}{\lambda}[/tex] = f
Therefore at constant speed:
f ∝ [tex]\frac{1}{\lambda}[/tex] (inversely proportional)
What type of waves is produced by moving or vibrating objects
Answer:
Mechanical Sound Waves
A mechanical wave is a wave that depends on the oscillation of matter, meaning that it transfers energy through a medium to propagate. These waves require an initial energy input that then travels through the medium until the initial energy is effectively transferred. Examples of mechanical waves in nature include water waves, sound waves, seismic waves and internal water waves, which occur due to density differences in a body of water. There are three types of mechanical waves: transverse waves, longitudinal waves, and surface waves.
Why is sound a mechanical wave? Sound waves move through air by displacing air particles in a chain reaction. As one particle is displaced from its equilibrium position, it pushes or pulls on neighboring molecules, causing them to be displaced from their equilibrium. As particles continue to displace one another with mechanical vibrations, the disturbance is transported throughout the medium. These particle-to-particle, mechanical vibrations of sound conductance qualify sound waves as mechanical waves. Sound energy, or energy associated with the vibrations created by a vibrating source, requires a medium to travel, which makes sound energy a mechanical wave.
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What is the relationship of tissues to cells?
Tissues make cells.
Cells make up tissues.
Tissues are use for cell growth.
Cells help tissue grow.
How much energy is released if a sample loses 0.05 kg mass through
radioactive decay?
Answer:
4.5 × 1015 J
Explanation:
Energy was released through this form of mass.
The energy released if a sample loses 0.05 kg mass through
radioactive decay is 45 ×10¹⁴ J.
What is Energy?The ability to do work is called energy.
The Einstein's formula can be used to find the energy released. Energy is the product of mass and the velocity of light in a vacuum squared.
Given that the mass is 0.05 kg and speed of light in vacuum is 3×10⁸ m/s.
E = 0.05 × (3×10⁸)²
E = 45 ×10¹⁴ J
The energy is released if a sample loses 0.05 kg mass through
radioactive decay is 45 ×10¹⁴ J.
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The function of the cell wall is to
A.make a organism rigid
B.provide internal support for an animal
C.control substances going in and out of organisms
D.make a plant cell rigid
Answer:
D.make a plant cell rigid
Explanation:
Cell wall is present only in a plant cell. Option A, B & C are functions of the cell membrane not the cell wall.
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[tex]\huge{\textbf{\textsf{{\color{pink}{An}}{\red{sw}}{\orange{er}} {\color{yellow}{:}}}}}[/tex]
D.make a plant cell rigid
thanks hope it helps.find the average speed of a person who swims 105 m in 70 s
Answer:
v = 1.5 m/s
Explanation:
Given that,
Distance covered by a person, d = 105 m
Time taken, t = 70 s
We need to find the average speed of the person. We know that the average speed is given by :
[tex]v=\dfrac{d}{t}\\\\v=\dfrac{105\ m}{70\ s}\\\\v=1.5\ m/s[/tex]
So, the average speed of the person is equal to 1.5 m/s.
a bottle with a volume of 694 L contains how many moles of O2 gas at STP
Answer:
Solution given:
22.4 liter of O2=1 mole of O2
694litre of O2=[tex] \frac{1}{22.4} \times 694[/tex]
=30.98or 31 mole of O2
In nuclear fission reactions, what causes the atom's nucleus to become
unstable
Answer:
the forces i think
Explanation:
The absorption of a free moving neutron by the atoms nucleus
(A P E X)
Write the balanced nuclear equation.
263
1.
Sg
254 Rf + A He
106
104
4
2.
211
At
83
He
2
3.
248
96
Cm + He
4
-
235
U
92
+
He
4.
2
Answer:
pag pinag balik tad moyan tama magiging tama sagot nya promise jslsh
electronics configuration
Answer:
Electronic configurations describe each electron as moving independently in an orbital, in an average field created by all other orbitals.
Explanation:
A type of symbiosis where one organism benefits, while the other organism is neutral.
Mutualism
Parasitism
Commensalism
Predation
Answer:
Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected. One species typically uses the other for a purpose other than food.
what is the similar about the formula for hydrochloric acid and that for sodium chloride
Explanation:
Sodium Chloride is neutral whereas hydrochloric acid is an acid. 2. Sodium Chloride is solid while hyrdochloric acid is a gas.
What are the bronsted lowry acids in the following equilibrium reaction CN+H2O
Answer:
dbdbdbdjdbdjdb zbdjdjdjdirfjfjrjdudhdhdhd
The geometry of a ______________ makes it a very stable shape.
Answer:
triangles
Explanation:
Isotonic compound have high melting point. Why ? Name the ions present in CaS.
Pls answer fastly ..
Explanation:
Because a large amount of energy is required to break the strong inter-ionic attraction.
CaS => Ca2+ & S2-