Answers
Answer:
In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.
i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.
This type of reaction is called neutralization.
ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.
So, the color change of the mixture at the end point is from pink to colorless.
iii) same explanation from question i,
HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
iv) no. of moles = volume (in dm3) x concentration
hence,
no. of moles of NaOH used = 25/1000 x 0.1
= 0.0025 mol
From the equation in (iii), since the mole ratio of HCl : NaOH = 1:1, meaning 1 mole of HCl reacts completely with 1 mole of NaOH.
This also means that the no. of moles of NaOH reacted equals to the no. of moles of HCl needed to react with it, which is 0.0025 mol.
Given the concentration of HCl in solution P is 0.1 mol /dm3. (pls correct me if I misunderstood your comment),
if v is the volume of HCl needed,
0.0025 = 0.1 v
v = 0.025 dm3
also = 25 cm3
Answer:
In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.
i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.
This type of reaction is called neutralization.
ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.
So, the color change of the mixture at the end point is from pink to colorless.
Explanation:
Related Questions
Help ya girl out plz
Answers
Answer:
The correct option is B
Explanation:
just did it edg 2020.
Answer:
the answer is c
Explanation:
Na-23 has 12 neutrons. What is it’s atomic number?
Answers
Answer:
11 Protons
Explanation:
Na-23 shows the mass of the element as 23. Therefore subtract 12 neutrons from the mass to get # of protons which is = to atomic #.
The atomic number of 23-Na is 11. It can be calculated from the number of protons present in the nucleus of an atom.
The atomic number is a fundamental property of an element and represents the number of protons found in the nucleus of an atom. It uniquely identifies each element on the periodic table. In a neutral atom, the atomic number also indicates the number of electrons present in the atom, as the number of protons and electrons in an atom are equal.
For example, hydrogen has an atomic number of 1, indicating that it has one proton in its nucleus. Oxygen has an atomic number of 8, indicating that it has eight protons in its nucleus.
The atomic number determines the element's position in the periodic table and provides important information about its properties and behavior.
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For a system, H2(g) + I2(g) ⇌ 2 HI(g), Kc = 62.9 at 750 K. 2.80 moles of HI were placed in a 10.0-liter container, brought up to 750 K, and allowed to come to equilibrium. Which situation described below is true, at equilibrium?
a. [HI] = 2 × [H2]
b. [HI] = [H2]
c. [HI] < [H2]
d. [HI] > [H2]
e. [H2] > [I2]
Answers
Answer:
d. [HI] > [H2]
Explanation:
The explanation at equilibrium is shown below:-
Data provided [tex]H_2(g) + I(g) \rightleftharpoons 2HI_(g)[/tex]
Initial concentration - - [tex]\frac{2.80}{10}[/tex] = 0.280 M
At equilibrium x x 0.280 - 2x
[tex]K_c = \frac{(HI)^2}{(H_2)(I_2)} = 62.9[/tex]
[tex]= \frac{(0.280 - 2x)^2}{x^2} = 62.9\\\\4x^2 - 1.12x + 0.0784 = 62.9x^2[/tex]
After solve the above equation we will get
x = 0.0282 M
Therefore at equilibrium
[tex][H_2] = [I_2] = x = 0.0282M\\\\[/tex]
[tex][HI] = 0.280 - 2x = 0.2236 M[/tex]
Hence, the correct option is d.
The volume of a sample of pure HCl gas was 221 mL at 20°C and 111 mmHg. It was completely dissolved in about 50 mL of water and titrated with an NaOH solution; 18.7 mL of the NaOH solution was required to neutralize the HCl. Calculate the molarity of the NaOH solution.
Answers
Answer:
[tex]molarity =6.9\times 10^{-3}\ M\\[/tex]
Explanation:
We know that , the reaction of HCl and NaOH is given as follows
[tex]NaOH+HCl=NaCl +H_2O[/tex]
Given that
Pressure = 111 mm Hg
[tex]P=111\times 13.6\times 10^{-3}\times 9.81\times 1000=14.809\ kPa[/tex]
Temperature = 20°C
T=20+273=293 K
Volume= 221 m L
V=0.221 L
Number of moles of HCl is given as follows
[tex]n=\dfrac{P\times V}{R\times T}\\n=\dfrac{0.148\times 0.221}{0.821\times 293}=1.3\times 10^{-4}\ moles[/tex]
From the above reaction we can say that
Number of moles of HCl=Number of moles of NaOH
Volume of NaoH is given as follows
V=18.7 = 0.0187 L
Therefore molarity
[tex]molarity =\dfrac{n}{V_{NaOH}}\\molarity =\dfrac{1.3\times 10^{-4}}{0.0187}=6.9\times 10^{-3}\ M\\molarity =6.9\times 10^{-3}\ M\\[/tex]
What is the [tex]K_{c}[/tex] Expression for the following reaction [tex]C_{6}H_{12}O_{6} + O_{2} \ \ - \ \ \textgreater \ 6H_{2}O+6CO_{2}[/tex] NO ABSURD ANSWERS!
Answers
Answer:
[tex]\boxed{\mathrm{view \: explanation}}[/tex]
Explanation:
This is an irreversible reaction, we cannot derive any [tex]\mathrm{K_c}[/tex] expression for it. The [tex]\mathrm{K_c}[/tex] expression can only be derived for reversible reactions and not irreversible reactions. We cannot derive the [tex]\mathrm{K_c}[/tex] expression for this reaction.
When N2gas is passed through water at 293k.how many moles of N2 dissolve in 1litre water
Answers
Answer: 7 milimoles of [tex]N_2[/tex] dissolve in 1 litre water.
Explanation:
Given: [tex]N_2[/tex] gas is passed through water at 293K.
Assumption :[tex]N_2[/tex] exerts a partial pressure of 0.987 bar.
Take : Henry's constant [tex]p_N_2[/tex] = 76.8 Kbar
[tex]K_H=76800[/tex]
To find : Number of moles of [tex]N_2[/tex] gas dissolve in 1 litre water.
According to Henry's law,
[tex]p_N_2=K_HX_{N_2}[/tex]
[tex]\Rightarrow\ 0.987=76800X_{N_2}[/tex]
[tex]\Rightarrow\ X_{N_2}=\dfrac{0.987}{76800}=0.0000128515625\approx1.29\times10^{-5}[/tex]
moles in 1 liter of water = [tex]\dfrac{1000}{18}=55.56\ [\text{Molar mass of }H_2O=18\ g][/tex]
Let n= moles of nitrogen
Total moles = 55.56+n
So,
[tex]X_{N_2}=\dfrac{n}{55.56+n}=1.29\times10^{-5}\\\\\Rightarrow\ 55.56\times1.29\times10^{-5}+1.29\times10^5n=n\\\\\Rightarrow\ n- 1.29\times10^5n=0.000714033\\\\\Rightarrow\ 0.999987n=0.000714033\\\\\Rightarrow\ n\approx7\text{ milimoles}[/tex]
Hence, 7 milimoles of [tex]N_2[/tex] dissolve in 1 litre water.
What percentage of the total incoming radiation to the Earth reaches the ground? 20 30 40 70
Answers
Answer: 22.5 percent of incoming solar radiation goes directly to the surface of the Earth and is absorbed.
Explanation: Transfer of radiation through a planet's atmosphere. A planet and its atmosphere, in our solar system, can radiate back to space only as much energy as it absorbs from incoming solar radiation.
Answer:
Explanation:
I have the notes
"Only about 40 percent actually reaches the surface of the earth"
"our atmosphere and clouds reflect bout 40 percent of incoming solar radiation back into outer space"
"The remaining 60 percent is responsible for warming the earth"
"About 20 percent of this radiation is absorbed directly by the atmosphere"
A container initially holds 5.67 x 10^10-2 mol of propane and has a volume of V1. The volume of the container was increased by adding an additional 2.95 x 10^-2 mol of propane to the container, so that the container has a final volume of 1.93 L. If the temperature and pressure are constant, what was the initial volume of the container ,V1?
Answers
Answer:
The initial volume of the container was 1.27L
Explanation:
Avogadro's law states that under the same pressure and temperature, equal moles of gases occupies equal volume. The equation is:
V₁n₂ = V₂n₁
Where V is volume and n moles of 1, initial state and 2, final state.
In the problem, initial moles are 5.67x10⁻², final moles after the addition are:
5.67x10⁻² + 2.95x10⁻² = 8.62x10⁻² moles
And, after the addition, the volume is 1.93L.
Replacing in Avogadro's law:
V₁×8.62x10⁻² moles = 1.93L×5.67x10⁻² moles
V₁ = 1.27L
The initial volume of the container was 1.27LA climber is attached to a vertical rope that has a tension of 785 N. If the
climber has a mass of 85 kg, what is the net force on the climber?
O A. 48 N up
OB. 542 N up
O C. 700 N down
O D. 48 N down
SUBMIT
Answers
Answer:
D. 48 N down
Explanation:
Given that:
Mass of climber = 85 kg, Tension on rope = 785 N, acceleration due to gravity = 9.8 m/s²
To calculate the net force on the climber, we need to first calculate the weight of the climber. Since the climber is affected by the earth gravity, the weight of the climber is the product of his mass and the acceleration due to gravity, therefore:
Weight = mass × acceleration due to gravity = 85 kg × 9.8 m/s² = 833 N
The weight of the climber is acting downwards while tension on the rope is acting upwards, therefore:
Net force on the climber = 785 N - 833 N = - 48 N
This means that the net force on the climber is 48 N downwards
Answer:
48 N down
Explanation:
Ayepecks
Volume occupied 3.52x10^32 moluchles
of Mathane (CH4)
1) At STP
Answers
Answer:
volume = 13097674418.528dm³
Explanation:
n = (3.52)*10^32/(6.02)*10^23)
n = (584717607.97)
n = volume /molar volume
molar volume at stp = 22.4dm³
volume= 584717607.97 x 22.4
volume = 13097674418.528dm³
Based on my previous question I have posted.. Answer this.. It's the continuation
Table 7.3 is different
Answers
Answer:
We don't know what solvent X and solvent Y are, but from the chart, we can see that in solvent X, hydrochloric acid can conduct electricity (bulb lights up), and react with calcium carbonate.
So, we can say the electrical conductivity when HCl is dissolved in solvent X is high, and when HCl is dissolved in solvent Y, the electrical conductivity is low (because light bulb doesn't light up).
Additionally, in solvent X, HCl ionizes, this shows the property of acids: reacts with carbonates to give CO2 (because CO2 reacts with lime water to make it cloudy).
In solvent Y, HCl does not ionize, so there is no reaction between acid and calcium carbonate.
what is difference between vapourization and boiling point?
Answers
Answer:
Vaporization is basically just evaporation which does not require nearly as much heat and happens naturally however when it comes to boiling point this is the point where water has been heated enough to start bubbling and changing state slowly.
Explanation:
Who is john Dalton ?
Answers
Answer:
He is a English chemist physicist and meteorologist. He is best known for the atomic theory
Answer:
John Dalton was a scientist.
Explanation:
How many significant figures are there in 6.07x10^-15?
Answers
Answer:
3
Explanation:
6.07 has 3 digits and all are significant
Which type of river is similar to a mature river, but flows more slowly so has less power to change the landscape? Select one: a. Youthful River b. Mature River c. Old Age River
Answers
Answer:
The correct option is;
C. Old Age River
Explanation:
Among the three stages of the development of a river, which are the youthful, mature, and old age stages, the old age river is least dynamic
The water is very slow moving with a low gradient and lesser erosive power to alter the landscape which results in the appearance of flood planes
Examples of old age rivers include, lower Ganges, lower Nile, Indus, and Yellow rivers
Old age rivers are characterized by a broad shape, with a wide flood plane, a very gentle gradient and the water current is low.
Answer:c
Explanation:
old age river
The structures found in a living cell can be compared to the parts of a factory that produces cars. Which part of the factory is most similar to the nucleus of a living cell? *
Answers
The computers that help control the machines in the factory
pls help...
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. What step do you need to take next? A. Add ethanol B. Add restriction enzymes C. Add minisatellites D. Add radioactive probes
Answers
C. Add minisatellites
Explanation: hope this helps
Add minisatellites. Hence, option C is correct.
What is Electrophoresis?Electrophoresis is a laboratory technique used to separate DNA, RNA or protein molecules based on their size and electrical charge.
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. you need to add minisatellites.
Hence, option C is correct.
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Energy from a reaction was determined to be 3870 J using a water calorimeter, when burning 9.00 grams of H2. What is the total enthalpy of the reaction?
Answers
Answer:
860 J / mol
Explanation:
Enthalpy = Energy / no. of moles
no. of moles = mass / molar mass
Take the atomic mass of H = 1.0,
molar mass of H2 = 1.0 x 2
= 2.0
no. of moles of H2 = 9.00/2
= 4.5 mol
Hence,
Enthalpy = 3870 / 4.5
=860 J / mol
For reaction: 2 C + O2 --> 2 CO2 If 5.50 g C was reacted with enough O2, what would be the volume (in liter) of the CO2 generated at STP? (0 C and 1 atm)
Answers
Answer:
10.2 L of CO₂
Explanation:
Our reaction is:
2C + O₂ → 2CO₂
We convert the mass of C, to moles:
5.50 g / 12g/mol = 0.458 moles
Ratio is 2:2, so if 2 moles of C can produce 2 moles of CO₂ then 0.458 moles of C would produce 0.458 moles of gas.
By the Ideal Gases Law, we know that 1 mol of gas is contained in 22.4L, so:
0.458 mol . 22.4L / 1mol = 10.2 L
Si el elemento "X" tiene 8 protones y el elemento "Y" tiene 11 protones, al reaccionar ¿Qué tipo de enlace pueden formar? Seleccione una: a. Metálico. b. Covalente puro. c. Covalente polar. d. Iónico.
Answers
Answer:
D; Iónico
Explanation:
El elemento con 8 protones es oxígeno, mientras que el elemento con 11 protones es sodio.
El sodio es un metal alcalinotérreo, mientras que el oxígeno no es un metal.
En general, cuando tenemos un elemento metálico como el sodio, que se une con uno no metálico como el oxígeno, el tipo de enlace formado como resultado de la transferencia completa de electrones desde la capa de valencia del sodio a la capa de valencia del oxígeno para completar su propia configuración de octeto se denomina enlace electrovalente o, más generalmente, enlace iónico
How many atoms are in 10g of Al
Answers
Answer:
2.22 x 10²³
Explanation:
number of atoms = mole x 6 x 10²³first we have to find number of moles
moles = mass(g) / molar mass (Mr) (g/mol)mol = 10/27
mol= 0.37 mol
Now,
number of atoms = mole x 6 x 10²³
= 0.37 x 6 x 10²³
= 2.22 x 10²³
When Niels Bohr refined the model of an atom,what new idea did he include?
Answers
Answer:
Niels Bohr, refined the model of an atom by proposing a quantized shell structure atomic model in order to describe how the electrons are able to maintain stable orbits around the nucleus
Based on the predictions of classical mechanics the electron motion of the Rutherford model was unstable as the electrons where expected to have lost some energy during motion and thus having to come rest in the nucleus
According to the modification by Neils Bohr in 1913, electrons move in shells or orbits of fixed energy and emission of electromagnetic radiation takes place only when electrons changes the orbit in which they move
Explanation:
using equation of reaction mention 4 methods of preparation of hydrogen
Answers
Explanation:
1. Displacement of hydrogen from water by using metal
2. Electrolysis of water using the apparatus known as the HOFMAN VOLTAMETER
3. Cracking of petroleum
4. Action of steam on hot coke
The coefficients in a chemical equation represent
the
Select one:
a. masses, in grams, of all reactants and
products,
O b. relative numbers of moles of reactants and
products,
c. number of atoms in each compound in a
reaction.
O d. number of valence electrons involved in the
reaction
Answers
Answer:
the answer is C
''number of atoms in each compound in a reaction.''
Explanation:
its a fact
The coefficients in the chemical equation represent relative numbers of moles of reactants and products. Therefore, option B is correct.
What is the chemical equation?A chemical equation can be explained as the representation of a chemical reaction in terms of chemical symbols. A chemical equation exhibits reactants participating, formed products in the reaction, and an arrow representing the direction of the chemical reaction.
The chemical equation in which the number of atoms of each element is equal on both sides of the chemical equation is known as a balanced chemical equation.
The law of conservation of matter needed to be followed while balancing a chemical equation.
The total mass of all elements on the reactant side should be equal to the total mass of all elements on the product side in a balanced chemical equation. The coefficients represent a number of moles of reactants and products.
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A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion. B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion. C. If Assertion is true statement but Reason is false. D. If Assertion is false and Reason is true Assertion: .Formation of soluble products from insoluble ones is called precipitation. Reason : Precipitation involves formation of insoluble products from soluble ones
Answers
Answer:
D- Assertion is false and Reason is true
Explanation:
Precipitation is said to have occurred when an insoluble product is formed from soluble ones. Let us take an instance;
BaCl2(aq) + H2SO4(aq) -------> BaSO4(s) + 2HCl(aq)
The barium sulphate so formed is an insoluble product obtained from the reaction of soluble barium chloride and sulphuric acid. This is a typical example of a double replacement reaction as the both ions exchanged partners.
Thus, the assertion is false but the reason is true.
Which event is most likely occurring? diffusion because particles move from regions of high concentration to regions of low concentration diffusion because particles move from regions of low concentration to regions of high concentration effusion because there is a movement of a gas through a small opening into a larger volume effusion because there is a movement of a gas through a large opening into a smaller volume
Answers
Answer: c
Explanation: effusion because there is a movement of a gas through a small opening into a larger volume
What is the correct formula for the Ksp of the reaction MgF2(s) – Mg2+ (aq) + 2F (aq)?
Ksp = [Mg2+][F]
Ksp =[Mg2+][F]2
Ksp = 2[Mg2+][F]
Ksp = [Mg2+][F]
Answers
Answer:
Ksp = [Mg₂⁺][F⁻]²
Explanation:
Ksp is the equilibrium constant for a solid dissolving in an aqueous solution. The equilibrium constant for a reaction is always products over reactants.
MgF₂ (s) ⇒ Mg₂⁺(aq) + 2F⁻(aq)
The equilibrium constant would be K = [Mg₂⁺][F⁻]². Since MgF₂ is solid, it is not included in the equilibrium expression.
Therefore, Ksp would be the same as the equilibrium constant.
Ksp = [Mg₂⁺][F⁻]²
Hope this helps.
Answer:
Ksp = [Mg2+]3 × [PO43-]2
Explanation:
edge 2021
someone plz plz answer this hurry plz it
Answers
Answer:
b
Explanation:
A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. The titration curve above was obtained with pH at equivalence point of around 8. The unknown compound is ________.
Answers
Answer:
Weak acid
Explanation:
A titration curve is a graphical description of the change in pH of the solution in the conical flask as the reagent is added from the burette. A titration curve can be plotted for the different kinds of acid and base titrations. The volume of the titrant is always plotted as the independent variable and the pH of the solution as the dependent variable. The equivalence point is read off from the titration curve. A titration curve is very important because it shows the pH at various points during the titration.
A weak acid/strong base titration leads to an equivalence point above 7. From the question, we were told that the pH at equivalence point lies around 8. Hence the unknown substance must be a weak acid.
Why are the oxidation and reduction half-reactions separated in an
electrochemical cell?
Answers
Answer:
Electrochemical cells typically consist of two half-cells. The half-cells separate the oxidation half-reaction from the reduction half-reaction and make it possible for current to flow through an external wire.
Explanation: