Answer: The molality of this solution is 1.7 m
Explanation:
Depression in freezing point:
[tex]T_f^0-T^f=i\times k_f\times m[/tex]
where,
[tex]T_f[/tex] = freezing point of solution = [tex]-70.55^0C[/tex]
[tex]T_f^0[/tex] = freezing point of pure chloroform = [tex]-63.5^0C[/tex]
[tex]k_f[/tex] = freezing point constant of benzene = [tex]4.07^0Ckg/mol[/tex]
m = molality
i = Van't Hoff factor = 1 (for non-electrolyte)
[tex]-63.5-(-70.55)^0C=1\times 4.07^0Ckg/mol\times m[/tex]
[tex]7.05=1\times 4.07^0Ckg/mol\times m[/tex]
[tex]m=1.7[/tex]
Thus the molality of this solution is 1.7 m
Which of the following is a halogen?
O A. Neon (Ne)
B. Iodine (1)
O C. Oxygen (0)
O D. Potassium (K)
Answer:
[tex]\boxed{\mathrm{Iodine}}[/tex]
Explanation:
Halogens are elements in group 17 or 7 in the periodic table.
Iodine is a halogen.
Therefore, iodine, an Halogen
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what will happen if a candle will be covered with an inverted jar filled will nitrogen
Answer:
The flame will burn out
Explanation:
The oxygen will be kept out of the jar, without oxygen the flame cannot last long. The flame will eventually burn out. Nitrogen gas has no role to play in the burning. Nitrogen slows down the burning rate.
what are the property of electrons
Answer:
basically an atom consist of electons and protrons .
electrons have a negative charge and in a circut the charge of electorns is more.
Answer:
listed below.
Explanation:
Few properties of electrons include:
- Electrons are subatomic particles with an electric charge of -1.
- Electrons have mass of approximately 1/1836 that of the proton.
- Electrons revolve around the nucleus of the atom.
- Electrons spin around their own axis.
sodium has 11 protons 12 neutrons. what is the isotope nation
Answer:
these are two atoms which have the same number of protons but different number of neutrons
The table shows the conditions during two trials of a reaction.
Answer:
The correct option is;
The reaction pathway for the trials is different
Explanation:
The effect of a catalyst in a chemical reaction is to increase the rate of a reaction by changing the pathway or mechanism of the reaction and/or to lower the transition state's energy thereby lowering the activation energy of the reaction
The pathway of the reaction is changed by the catalyst by the formation of intermediate compounds by the catalyst which require lower activation energy to form the products than the original non-catalyzed reactants. In the process the catalyst is regenerated, thereby, not taking part in the reaction.
Name the hydro carbon.... I really need your help guyz
Answer:
The given hydrocarbon is Butanol
Why are the oxidation and reduction half-reactions separated in an
electrochemical cell?
Answer:
It makes the current viable enough to pass through an exterior wire.Explanation:
Electrochemical cells primarily comprise of two half-cells. These half-cells assist in isolating the oxidation and reduction half-reactions. These two reactions are linked by a wire which allows the current to move from one edge to the other. The oxidation at the anode and the reduction take place at the cathode and the addition of a salt bridge helps in completing the circuit and permits the current to flow and leads to the generation of electricity.
how many different d orbits are within the 3d sublevel
Answer:
Its 5
Explanation:
In heating and melting curves, what is the name of the heat associated with the solid-liquid phase? A. Heat of formation B. Heat of fusion C. Heat of sublimation D. Heat of vaporization
Answer:
C I believe not quite sure tho
In heating and melting curves, the name of the heat associated with the solid-liquid phase is Heat of fusion.
What is the Heat of fusion ?
The standard fusion enthalpy is the amount of thermal energy required for a single mole of a substance to change states from a solid to a liquid or vice versa is known as the heat of fusion or specific melting heat. The melting point is the temperature at which it takes place, and it is also known as the latent heat of fusion or the enthalpy change of fusion.The temperature of a liquid or solid goes down when thermal energy is taken away. The temperature rises when heat and energy are added. However, additional energy—the heat of fusion—is required at the melting point—the transition point between solid and liquid. The molecules of a substance need to become more organized in order to change from liquid to solid. They require the withdrawal of additional heat in order to maintain their solid state. In the opposite direction, additional heat is required to induce the disorder from the solid crystal to the liquid.The temperature of water as it freezes can be measured to observe the heat of fusion. When you place a closed container of room temperature water in a very cold environment, say 20 °C, the temperature will gradually fall until it is just below the freezing point. After that, the temperature rises and stays the same as the water crystallizes. The temperature will again fall steadily after it has completely frozen.The heat of fusion causes the temperature to stop falling at (or just below) the freezing point. Before the temperature can continue to fall, the energy from the heat of fusion must be removed—the liquid must transform into a solid.
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Two samples of sodium chloride were decomposed into their constituent elements. One sample produced 2.84 g of sodium and 4.37 g of chlorine. Which of the following could be the results of the decomposition of the other sample, being consistent with the law of constant composition (also called the law of definite proportions or law of definite composition)?
a) 4.17 g of sodium and 3.75 g of chlorine
b) 4.17 g of sodium and 6.42 g of chlorine
c) 4.17 g of sodium and 1.05 g of chlorine
d) 4.17 g of sodium and 12.1 g of chlorine
Answer:
The correct answer is b) 4.17 g of sodium and 6.42 g of chlorine
Explanation:
According to the law of definite proportions a chemical compound is composed always by the same elements in the same proportions by mass. In this case, the proportion of the elements by mass will be 4.37 g of chlorine (Cl) per 2.84 g of sodium (Na):
4.37 Cl/2.84 g Na= 1.54
We can calculate the proportions of the results in order to see which is the correct:
a) 3.75 g Cl/4.17 g Na = 0.899
b) 6.42 g Cl/4.17 g Na = 1.539 ⇒ ≅1.54
c) 1.05 g Cl/4.17 g Na = 3.971
d) 12.1 g Cl/4.17 g Na = 2.901
The option in which the proportion Cl/Na is equal to 1.54 is option b
Explain how temperature and volume of a gas are related and use that to make a prediction about
how you can use this information to calculate absolute zero.
Answer:
See explanation
Explanation:
Charles law gives the relationship between volume and temperature of a gas. Charles law States that, the volume of a given mass of gas is directly proportional to its temperature at constant pressure.
Theoretically, it is assumed that when the absolute zero temperature has been achieved, the volume of any ideal gas will be found to be equal to zero. If the volume of the gas is zero, it now implies that all molecular motion will be stopped. This does not happen in real gases as all gases are found to condense to solids or liquids when this temperature is exceeded.
When volume is plotted against temperature, volume of the gas approaches zero at t = −273.15 °C, which is the x-intercept of the Charles law graph. Below this temperature, we can only get negative values of volume which does not exist hence, −273.15 °C is the lowest attainable temperature also known as the absolute zero.
(Help please!! important test!!!) What property of matter are you measuring if you are using a triple beam balance? (2 points)
volume,
gravity,
mass, or
size
Answer:
mass
Explanation:
The triple beam balance is an instrument used to measure mass very precisely.
Label the chemical equation.
2 Mg(s) + O2(g) → 2 MgO(s)
Label the chemical equation.
2 Mg(s) + O2(g) → 2 MgO(s)
Answer:
Kindly check Explanation
Explanation:
Given the chemical equation:
2 Mg(s) + O2(g) → 2 MgO(s)
2 molecules of Magnesium + Oxygen gas (Reactant)
→ ( yield)
2 molecules of magnesium oxide (product)
2 in Mg and MgO (coefficients)
2 in Oxygen gas (subscript)
Solid (s) - physical state of Reactant Mg
Gas (g) - physical state of Reactant O2
Solid (s) - physical state of product 2MgO
True or False a. Sodium chloride is the main salt found in sea water. ……………………………………………………………………. b. Potassium bromide salt is not found in sea water ……………………………………………………………………. c. Both evaporation and electric conduction techniques prove that sea water contain the dissolved salts. …………………………………………………………………….. d. The amount of fresh water is greater than 5% of the total Earth water. …………………………………………………………………….. e. In water treatment process, filter membrane is used to remove fine particles and other impurities from water. …………………………………………………………………………....
Answer:
A is true NaCl
B is false K2Br
C is true
D false its only 0.03 percent
E is true
During which two minute time period is the temperature of the water changing fastest? Select one: a. 0-2 minutes b. 2-4 minutes c. 4-6 minutes d. 6-8 minutes Clear my choice
Answer:
b. 2-4
Explanation:
Look at the slope of the line, between 0-2 and 4-6 the slope is only 10, but between 2-4 the slope is 20, so that's when the temperature is changing the fastest. In the same time it took for the water to increase by 20 degrees between 0-2 and 4-6, the temperature of the water increased by 40 degrees between 2-4 so that's when the change is the fastest.
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?
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 1.27Lformula of sodium bicarbonate
please help me with this
Answer:
NaHCO₃
Explanation:
Sodium bicarbonate (baking soda) is a chemical compound with the formula NaHCO₃.
How did Bohr describe the arrangement of particles within an atom?
A. Protons and electrons form the nucleus, with neutrons
orbiting it.
O B. Neutrons make up the atom's nucleus, with electrons and
protons orbiting it.
c. Protons make up the atom's nucleus, with electrons and
neutrons orbiting it.
O D. Protons and neutrons form the nucleus of the atom, with
electrons orbiting it.
Bohr describe the arrangement of particles within an atom by: O D. Protons and neutrons form the nucleus of the atom, with electrons orbiting it.
Who is Niels Bohr?This hypothesis states that the atom's core is a small, compact, positively charged nucleus. Protons which have a positive charge and neutrons which are neutral are both found in the nucleus.
Specific energy levels or electron shells are where the negatively charged electrons orbit the nucleus. Due to the quantization of these energy levels, only a limited number of discrete energy states are accessible to electrons.
Therefore the correct option is D.
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what is heat energy in science
Answer:
Heat energy is the result of the movement of tiny particles called atoms, molecules or ions in solids, liquids and gases. Heat energy can be transferred from one object to another. the transfer or flow from one object to another is called heat.
hopefully this helped :3
Seawater is highly saline, which means it contains large amounts of dissolved salt. When seawater freezes and icebergs form, the water in the iceberg doesn’t take the salt with it. What effect will this phenomenon have on the concentration of salt in the water around the iceberg?
Answer:
Because the amount of liquid water decreases and the amount of dissolved salt remains constant, the concentration of salt in the liquid water around the iceberg will increase.
Explanation:
Answer:
Because the amount of liquid water decreases and the amount of dissolved salt remains constant, the concentration of salt in the liquid water around the iceberg will increase.
Explanation:
PLATO exact answer
If the external vapor pressure is 2.0 atm , what is the vapor pressure of the water at its boiling point?
Answer:
22
Explanation:
22
A 2.00L flask was filled with 4.00 mol of HI at a certain temperature and given sufficient time to react. At equilibrium the concentration of H2 was 0.400 M. Find the equilibrium concentrations of I2 and HI and then find the Keq at this temperature.
Answer:
The equilibrium concentration of I₂ is 0.400 M and HI is 1.20 M, the Keq will be 0.112.
Explanation:
Based on the given information, the equilibrium reaction will be,
2HI (g) ⇔ H₂ (g) + I₂ (g)
It is given that 4.00 mol of HI was filled in a flask of 2.00 L, thus, the concentration of HI will be,
= 4.00 mol/2.00 L
= 2.00 mol/L
Based on the reaction, the initial concentration of 2HI is 2.00, H₂ is 0 and I₂ is O. The change in the concentration of 2HI is -x, H₂ is x and I₂ is x. The equilibrium concentration of 2HI will be 0.200-x, H₂ is x and I₂ is x.
It is given that at equilibrium, the concentration of H₂ or x is 0.400 M.
Now the equilibrium concentration of HI will be,
= 2.00 -2x
= 2.00 - 2 × 0.400
= 1.20 M
The equilibrium concentration of I₂ will be,
I₂ = x
= 0.400 M
The equilibrium constant (Keq) will be,
Keq = [H₂] [I₂] / [HI]²
= (0.400) (0.400) / (1.20)²
= 0.112
Thus, the Keq of the reaction will be 0.112.
Who is john Dalton ?
Answer:
He is a English chemist physicist and meteorologist. He is best known for the atomic theory
Answer:
John Dalton was a scientist.
Explanation:
The concentration of phenylephrine hydrochloride in a prefilled syringe is 10 mg/mL. What is the percentage concentration (w/v) of phenylephrine in the injection. (Answer must be numeric; no units or commas; round the final answer to the nearest WHOLE number.)
Answer:
The percentage concentration (w/v) of phenylephrine in the injection is 1 %.
Explanation:
The percentage concentration in w/v of the phenylephrine hydrochloride can be calculated as follows:
[tex]\%^{w}/_{v} = \frac{m}{V} \times 100[/tex]
Where:
m: is the mass of the solute in grams
V: is the volume of the solution in milliliters
The concentration of the phenylephrine hydrochloride is 10 mg/mL, so the percentage concentration is:
[tex]\%^{w}/_{v} = \frac{m}{V} \times 100[/tex]
[tex]\%^{w}/_{v} = \frac{10 \cdot 10^{-3} g}{1 mL} \times 100[/tex]
[tex]\%^{w}/_{v} = 1 \%[/tex]
Therefore, the percentage concentration (w/v) of phenylephrine in the injection is 1 %.
I hope it helps you!
How many electrons can the n = 4 shell hold? 8 16 32 64
Answer:
32Explanation
n = 4
Now,let's find the number of electrons:
[tex]2 {n}^{2} [/tex]
plug the value
[tex] = 2 \times {4}^{2} [/tex]
Evaluate the power
[tex] = 2 \times 16[/tex]
Multiply the numbers
[tex] = 32[/tex]
Hope this helps...
best regards
Electrons are the sub-particles present in atomic shells. The (Principal Quantum Number) n = 4 shell of the atom can hold 32 electrons in it. Thus, option c is correct.
What is Principal Quantum Number?Principal Quantum Number (n) is defined as the distance of the electron from the nucleus and its energy in the atom. It can also be said to know the position of the electron in the energy level along with the orbital size.
The Principle Quantum Number, n = 4 depicts the fourth shell or energy level of the atom that can hold a specific number of electrons in it.
The electrons present in the shell or the energy level are determined by,
2n²
Here, n = 4
Substituting the values above,
= 2 (4)²
= 2 (16)
= 32
Therefore, the n = 4 energy shell can contain 32 electrons.
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anne added a sample of hydrochloric acid to water and determined the pH to be 1.79. what is the poH of the solution?
Answer: 12.21
Explanation:
It is well known that the sum of pH + pOH = 14.
To get the pOH of the solution, we subtract 1.79 from 14.
pH + pOH = 14
pOH = 14 - 1.79 = 12.21
pOH = 12.21
What is the freezing point of a solution of 1.43 g mgcl2 in 100 g of water? Kf for water is 1.86°c/m for water.
Answer:
Change in T = i x m x kf. Where i is the number of particles the compound dissociates, m is the molality, and kf is the constant specific to water. MM of MgCl2 = 95.21 g/mol
MgCl2 will form three atoms....i = 3......1Mg + 2Cl
kf = 1.86
moles of MgCl2 = 1.43g/95.21 = 0.015
m = moles solute/ kg solvent = 0.015/.1kg = .15m
Change in T = (3)(.15)(1.86) = .838
This is the depression of the freezing point of water, it is negative because the water's new freezing point is its normal freezing point minus the change in T.
0 - .838 = -.838
Explanation:
Match each term below with its definition or description.
1 The point in a titration when the added amount of standard reagent is equal to the amount of analyte being titrated.
2 The analyte is titrated with the standard reagent and the volume of standard solution required to complete the reaction is measured.
3 A reagent that is pure and stable, which can be used directly after weighing.
4 The analyte that is being analyzed in the titration.
5 Standard reagent is added in excess to ensure complete reaction with the analyte. The excess reagent is then titrated with a second standard reagent.
6 A solution, whose concentration is known, often made from a reagent of known purity.
7 The standard reagent of known concentration that is added from a buret to the analyte solution.
8 The analyte does not react directly with the titrant so it is converted to another form which will react with the titrant.
9 The point in a titration when a change in the analyte solution is observed, indicating equivalency.
10 It is added to the analyte solution and aids in the observation of the completion of the reaction.
a) End Point
b) Indicator
c) Direct Titration
d) Back Titration
e) Indirect Titration
f) Primary Standard
g) Standard Solution
h) Titrand
i) Equivalence Point
j) Titrant
Answer:
1. Equivalence point
2. Direct titration
3. Primary standard
4. Titrand
5. Back titration
6. Standard solution
7. Titrant
8. Indirect titration
9. End point
10. Indicator
Explanation:
1. The equivalence point is the tiration point at which the quantity or moles of the added titrant is sufficient or equal to the quantity or moles of the analyte for the neutralization of the solution of the analyte.
2. Direct titration is a method of quantitatively determining the contents of a substance
3. A primary standard is an easily weigh-able representative of the mount of moles contained in a substance
4. A titrand is the substance of unknown concentration which is to be determined
5. The titration method that uses a given amount of an excess reagent to determine the concentration of an analyte is known as back titration
6. A standard solution is a solution of accurately known concentration
7. A titrant is a solution that has a known concentration and which is titrated unto another solution to determine the concentration of the second solution
8. Indirect titration is the process of performing a titration in athe reverse order
9. The end point is the point at which the indicator indicates that the equivalent quantities of the reagents required for a complete reaction has been added
10 An indicator is a compound used to visually determine the pH of a solution.
The titration has been the neutralization reaction in which the titrand and the titrant react to form the salt and the water and help in the determination of the qualitative and quantitative properties.
What is an Endpoint?In a titration reaction, the endpoint has been the point at which the equivalent amount of reagent has been completely neutralized.The Indicator has been the chemical that changes to indicate the endpoint of the reaction.Direct titration involves the reaction for the quantitative determination of the substances.The back titration can be given as the reaction in which the excess reagent is used to titrate the second standard reagent in the reaction.Indirect titration can be given as the reaction of the analyte to convert to another form and then the analysis with the titrant.The primary standard has been the known concentration of the pure and stable weighing reagent.The standard solution has been the solution of the known concentration in the reaction.Titrand has been the unknown sample that has to be analyzed.The equivalence point is the concentration point at which the quantity of titrant added to the titrand has been equal.Titrant has been the known concentration of sample that has been added to equivalent the unknown sample.Learn more about titration here:
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hello:)!! for the preparation of salts , I don’t really understand the part where acids react with insoluble bases. do I just memorise it? :) thanks!
Answer:
I think if u will clear your topic it would be more helpful.
But if u r unable to do it, then u can just memorise it.
See, i will try to help u.
Salts are formed when acids react with bases.
and this reaction is called neutralisation reaction.
e.g. HCl+NaOH=NaCl+H2O.
It is very easy.
Other examples:
H2SO4+Mg(OH)2=MgSO4+2H2O.
There may be some other reactant with acid like u have mentioned above.
hope it helps u....
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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
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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