Answer:
1.62
Explanation:
From the given information:
number of moles of benzamide [tex]=\dfrac{70.4 \ g}{121.14 \ g/mol}[/tex]
= 0.58 mole
The molality = [tex]\dfrac{mass \ of \ solute (i.e. \ benzamide )}{mass \ of \ solvent }[/tex]
[tex]= \dfrac{0.58 }{0.85 }[/tex]
= 0.6837
Using the formula:
[tex]\mathbf {dT = l \times k_f \times m}[/tex]
where;
dT = freezing point = 27
l = Van't Hoff factor = 1
kf = freezing constant of the solvent
∴
2.7 °C = 1 × kf × 0.6837 m
kf = 2.7 °C/ 0.6837m
kf = 3.949 °C/m
number of moles of NH4Cl = [tex]\dfrac{70.4 \ g}{53.491 \ g /mol}[/tex]
= 1.316 mol
The molality = [tex]\dfrac{1.316 \ mol}{0.85 \ kg}[/tex]
= 1.5484
Thus;
the above kf value is used in determining the Van't Hoff factor for NH4Cl
i.e.
9.9 = l × 3.949 × 1.5484 m
[tex]l = \dfrac{9.9}{3.949 \times 1.5484 \ m}[/tex]
l = 1.62
What is the difference between stored energy and usable energy
answer:
In biology, the energy that is stored in the bonds between compounds is termed as the chemical energy. This chemical energy is released and converted into different forms according to the functions of the body.
Potential energy can be described as the energy that is stored in an object. In physics, the energy that an object possesses while at rest is termed as the potential energy.
The energy that can be used during work is termed as the kinetic energy. In physics, kinetic energy can be described as the energy that an object possesses while in motion.
-- please mark the brainliest and click the thanks button if correct :)
Answer: The stored energy is termed as potential energy while the working energy is termed as kinetic energy. The electricity used in our homes is also a form of energy because it is a form of usable power. The places from which the different energies are obtained are known as energy sources.
What is the value of 4.698 after rounding it down to 3 significant figures?
Many compressed gases come in large, heavy metal cylinders that are so bevy that they need a special cart to move them around. An 80.0-L tank of nitrogen gas pressurized to 172 arm atm is left in the sun and heats from its normal temperature of 20.0 degrees Celsius to 140.0 degrees Celsius. Determine (a) the final pressure inside the tank and (b) the work, heat, and delta U of the process. assume that behavior is ideal and the heat capacity of diatomic nitrogen is 21.0 j/molk.
Answer:
a) final pressure inside the tank is 242.4 atm
b)
Work = 0
heat q = 1440.85 kJ
DU = 1440.85 kJ
Explanation:
Given that;
Pressure P1 = 172 atm
Volume V = 80 L
Temperature T1 = 20°C = ( 273.15 + 20) = 293.15 K
Temperature T2 = 140°C = ( 273.15 + 140) = 413.15 K
we know that, gas constant R = 0.0821 atm.L/mol.K
from the Ideal Gas equation;
pV = nRT1
n = pV/RT1
we substitute
n = (172 × 80) / (0.0821 × 293.15)
n = 13760 / 24.067615
n = 571.72 moles
now
P2 = nRT2/V2
P2 = (571.72 × 0.0821 × 413.15) / 80
P2 = 19392.5222 / 80
P2 = 242.4 atm
Therefore, final pressure inside the tank is 242.4 atm
b)
we know
w = -∫[tex]P_{ext}[/tex] dv
now, since there is no change in volume; dv = 0
so
w = 0
Work = 0
dU = cVDT
Cv = nCr,m
Cv = 571.72 × 21.0
Cv = 12007.12 J/k
DU = CvΔT
DU = 12007.12 × (413.15 - 293.15)
DU = 1440854.4 J
DU = 1440.85 kJ
DU = q + w
1440.85 = q + 0
heat q = 1440.85 kJ
Please help with whatever this is and go in number order
Dale is speaking to a group of students about the importance of extracurricular activities. He provides specific scenarios to show the audience how the information presented will affected them directly. Dale is fulfilling which goal of informational speaking?
to enhance understanding
to be heard
to maintain interest
to be remembered
Sally does the work in 2.3 hours and Pete does 2.5
Which of the following contains a polyatomic ion?
sodium iodide
carbon monoxide
Iron II oxide
ammonium chloride
Answer:
i think its oxide not too sure
Answer:
Its should be ammonium chloride.
A picture to help you with another question like this
What is the maximum mass of ammonia (NH3) that can be produced from the synthesis reaction of 781 g of nitrogen and 656 g hydrogen?
HINT: You will need to write a balanced chemical equation and perform 2 calculations before you can determine the answers.
How many molecules are there in 42gms of Na?
Why reaction of lead with dilute acid Cannot liberate hydrogen
Answer:
Copper does not reacts with dilute sulphuric acid, liberating hydrogen because copper is lower in the electromotive series than hydrogen. ... The metals above hydrogen in the activity series react with dilute sulphuric acid and dilute hydrochloric acid to liberate hydrogen.
Heat is most closely related to which kind of energy?
Answer:
radial energy because it's a heat energy!
Explanation:
There are more types but that's the closest in my opinion!!
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Thermal Energy
Explanation:
known as heat energy produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.
Classify the following compounds as binary ionic, ternary ionic, or molecular.
Answer:bro u already have an answer why are you asking?
Explanation:
An ionic compound has a generic formula of QR2.
Which elements could the Q and R represent?
Once you choose an answer, check it by plugging those elements into the QR2 formula to see if it looks right.
Q= Sodium R= Oxygen
Q= Magnesium R= Chlorine
Q= Oxygen R= Sodium
Q= Chlorine R= Magnesium
Answer:
Q= Magnesium R= Chlorine
Explanation:
The element Q should be magnesium and R is chlorine.
An ionic compound is a compound that is formed by the combination of a metal and non-metal. Such bonds forms when there is a transfer of electrons from the metals to the non-metals. This leaves a net positive charge on the metal and a negative charge on the non-metal.
The electrostatic attraction leads to the formation of the bond.
To solve this problem, the hypothetical compound is QR₂
Mg Cl
2 8 2 2 8 7
So, Mg transfers 2 electrons to two atoms of chlorine.
This leads to the formation of the compound MgCl₂
What is the amount of heat required to complete MELT a 200 gram sample of H2O(s)
Answer:
66800 J
Explanation:
From the question given above, the following data were obtained:
Mass (m) = 200 g
Heat (Q) required =?
The heat required to melt the 200 g sample of water can be obtained as:
Mass (m) = 200 g
Latent heat of water (L) = 334 J/g
Heat (Q) required =?
Q = mL
Q = 200 × 334
Q = 66800 J
Thus, 66800 J of heat energy is required to melt the sample of water.
Answer:
66800 J
Explanation:
How many cells are a result of Meiosis?
Answer:
2
Explanation:
Cells divide and reproduce in two ways, mitosis and meiosis. Mitosis results in two identical daughter cells, whereas meiosis results in four sex cells.
Conduction happens as energy flows from a warmer object to a cooler object. Which of the following is evidence of conduction?
Explanation:
Conduction is a form of heat transfer between one body and another. It usually occurs when a warmer object is in contact with a cooler one. Heat generally flows from a region of high temperature to a place at a lower temperature.
Conduction is very pronounced in solid bodies. The heat transfer causes a net transfer of the average kinetic energy of one body to the other. Some examples are: heating of iron by a hotter metallic body, the pot hand getting hotter as cooking continues, cooling of ice by touching it.Which of the following choices is not evidence supporting the theory of plate tectonics?
Answer:
B
Explanation:
According to bond energy tables, the triple bond of N2 is 946 kJ/mol while the bond of I2 is 151 kJ/mol. Based on simple chemical ideas about what molecular properties lead to activation energies, it is reasonable to expect that the reaction of H with N2 will have a higher activation energy than the reaction of H with I2.
1. Yes, I2 is heavier than N2.
2. No, bond energies do not matter much; lone pairs are crucial.
3. Yes, in both cases the reactant bond must be stretched by collisions and more energy is required for the stronger bond.
4. Yes, in both cases the reactant bond must be broken before the H can bond.
5. No, activation energies have nothing to do with bond energies.
Answer:
Yes, in both cases the reactant bond must be broken before the H can bond.
Explanation:
Let us remind ourselves of the basics of the collision theory. According to this theory, chemical reaction occurs because of the collision of particles of substances in a chemical reaction system.
This means that the bond between reactants must first be broken and new bonds formed in products. Activation energy is the minimum energy required for a reaction to occur. This energy goes into the rearrangement of reactant bonds to enable them to recombine and form products.
Since the N2 bond energy is far higher than the I2 bond energy, a greater degree of energy is needed overcome the energy barrier in the reaction of H2 with N2 compared to the reaction of H2 and I2 . Therefore, the activation energy for the reaction of H2 and N2 is much higher than the activation energy for the reaction of H2 with I2.
Given the equation:
4Al2O3 + 9Fe --> 3Fe3O4 + 8Al
If 27.5 g of Al2O3 reacted with 8.4 g of Fe, how many of Fe 3O4 are formed?
a) Calculate the limiting reactant
b) Calculate the number of grams of Al produced.
c) Calculate the number of grams of Fe3O4 produced.
d) Calculate the percent yield if 10g of Fe O4 were obtained?
Answer: a) [tex]Fe[/tex] is the limiting reagent
b) 3.59 g
c) 11.6g
Explanation:
[tex]4Al_2O_3+9Fe\rightarrow 3Fe_3O_4+8Al[/tex]
To calculate the moles :
[tex]\text{Moles of} Al_2O_3=\frac{27.5g}{102g/mol}=0.27moles[/tex]
[tex]\text{Moles of} Fe=\frac{8.4g}{56g/mol}=0.15moles[/tex]
According to stoichiometry :
a) 9 moles of [tex]Fe[/tex] require= 4 moles of [tex]Al_2O_3[/tex]
Thus 0.15 moles of [tex]Fe[/tex] will require=[tex]\frac{4}{9}\times 0.15=0.067moles[/tex] of [tex]Al[/tex]
Thus [tex]Fe[/tex] is the limiting reagent as it limits the formation of product and [tex]Al[/tex] is the excess reagent.
b) As 9 moles of [tex]Fe[/tex] give = 8 moles of [tex]Al[/tex]
Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{8}{9}\times 0.15=0.133moles[/tex] of [tex]Al[/tex]
Mass of [tex]Al=moles\times {\text {Molar mass}}=0.133moles\times 27g/mol=3.59g[/tex]
c) As 9 moles of [tex]Fe[/tex] give = 3 moles of [tex]Fe_3O_4[/tex]
Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{3}{9}\times 0.15=0.05moles[/tex] of [tex]Fe_3O_4[/tex]
Mass of [tex]Fe_3O_4=moles\times {\text {Molar mass}}=0..05moles\times 231.5g/mol=11.6g[/tex]
Why is this image a good model for the Law of Conservation of Mass?
Answer:
The Law of Conservation of Mass states that mass is neither created nor destroyed in chemical reactions. Since the number and type of atoms in the reactant side of the chemical equation are the same as on the product side, the Law of Conservation of Mass has been demonstrated.
Explanation:
In the answer.
The two main postulates that was given by Antoine Lavoisier are, oxygen play an important role in combustion and the other is mass of the reactant and product is conserved. Therefore, the given image is a good model for the Law of Conservation of Mass.
What is law of conservation of mass?According to Law of conservation of mass, mass can neither be created nor be destroyed. Mass can only be transformed from one form to another. The law of conservation of mass was given by Antoine Lavoisier.
Every reaction in nature follow the law given by Antoine Lavoisier that is mass is always conserved. Another postulated that was given by Antoine Lavoisier is the role of oxygen in combustion reaction. Combustion can not happen without presence of oxygen.
The image is a good model for the Law of Conservation of Mass as number and type of atoms on the reactant side and product side are the same.
Therefore, the given image is a good model for the Law of Conservation of Mass.
To know more about law of conservation of mass, here:
https://brainly.com/question/28711001
#SPJ2
Why do organisms eat food? Be sure to explain your answer.
Answer:
Organisms need to take food to get energy and perform life processes. A living organism undergoes many life processes like nutrition, respiration, digestion, transportation, excretion, circulation of blood, and reproduction. To perform all these life processes the organism needs energy and nutrients.
Explanation:
nnastarannnn his idea
which section from the article most emphasizes the role of technological development in the discovery of cells
Answer:
B. The microscope paved the way
Explanation:
This section from the article, "History of the Cell: Discovering the Cell", that emphasizes the role of technological development in the discovery of cells, is the subheading, "The microscope paved the way". In this subheading, the author narrated how Robert Hooke improved the existing microscope, and was able to discover the cell through it.
Further improvement of the simple microscope by Antonie van Leeuwenhoek led to the discovery of bacteria and protozoa.
Gluons carry
a
the weak force
b
gravity
c
Bosons
d
the strong force
e
electromagnetic force
Answer:
the answer is d
hope this helpssss
Define degree of hardness of water? Mention different units.
Answer:
Degree of hardness is defined as the number of parts of calcium carbonate or equivalent to various calcium and magnesium salts present in a million parts of water by mass.
Explanation:
General guidelines for classification of waters are: 0 to 60 mg/L (milligrams per liter) as calcium carbonate is classified as soft; 61 to 120 mg/L as moderately hard; 121 to 180 mg/L as hard; and more than 180 mg/L as very hard. Lime scale buildup inside a water pipe
Units: mg/l , ppm , kg/[tex]m^{3}[/tex] , ppb , g/L
Three resonance structures of the given anion are possible. One is given, but it is incomplete. Complete the given structure by adding nonbonding electrons and formal charges. Draw the two remaining resonance structures (in any order), including nonbonding electrons and formal charges. Omit curved arrows.
Answer:
Explanation:
The missing incomplete resonance structure is attached in the image below. From there, we can see the addition of the nonbonding electrons and its' formal charge which makes the resonance structure a complete resonance structure. The others two resonance structure that can be derived from the complete structure is also shown in the image. Out of these three structures, the structure that contributes most to the hybrid is the structure with the negative charge on the oxygen.
What is the function of the chloroplast? A. Breaks down sugar to make energy B. To hold the cell together C. To make animals green D. Uses sunlight to create glucose (sugar)
Answer:
D. Uses sunlight to create glucose (sugar)
Explanation:
The function of the chloroplast is that it uses sunlight to create glucose.
The chloroplast allows for light to be trapped which is used for the synthesis of glucose from carbon dioxide and water.
The chloroplast is a rich in a pigment called the chlorophyll. This chlorophyll is a green pigment which allows for the trapping of solar energy
This solar energy is used to carryout the photosynthetic reaction.
A desert that contains plants and animals that have been there a long time is
an example of
Please help me thanks so much!?!?!?
Answer:
Lighting the stove and cooking the meat are both chemical changes.
Explanation:
Both fire and cooking are chemical changes.
Answer:
the second one
Explanation:
definition of solubility
(science)
Answer:
th relative ability of a solute to devolve into a solvent
what divided by 700000 equals 4