Answer:
[tex]\Delta H_{f,C_3H_4}=276.8kJ/mol[/tex]
Explanation:
Hello!
In this case, since the equation we use to model the heat exchange into the calorimeter and compute the heat of reaction is:
[tex]\Delta H_{rxn} =- m_wC_w\Delta T[/tex]
We plug in the mass of water, temperature change and specific heat to obtain:
[tex]\Delta H_{rxn} =- (35000g)(4.184\frac{J}{g\°C} )(2.316\°C)\\\\\Delta H_{rxn}=-339.16kJ[/tex]
Now, this enthalpy of reaction corresponds to the combustion of propyne:
[tex]C_3H_4+4O_2\rightarrow 3CO_2+2H_2O[/tex]
Whose enthalpy change involves the enthalpies of formation of propyne, carbon dioxide and water, considering that of propyne is the target:
[tex]\Delta H_{rxn}=3\Delta H_{f,CO_2}+2\Delta H_{f,H_2O}-\Delta H_{f,C_3H_4}[/tex]
However, the enthalpy of reaction should be expressed in kJ per moles of C3H4, so we divide by the appropriate moles in 7.00 g of this compound:
[tex]\Delta H_{rxn} =-339.16kJ*\frac{1}{7.00g}*\frac{40.06g}{1mol}=-1940.9kJ/mol[/tex]
Now, we solve for the enthalpy of formation of C3H4 as shown below:
[tex]\Delta H_{f,C_3H_4}=3\Delta H_{f,CO_2}+2\Delta H_{f,H_2O}-\Delta H_{rxn}[/tex]
So we plug in to obtain (enthalpies of formation of CO2 and H2O are found on NIST data base):
[tex]\Delta H_{f,C_3H_4}=3(-393.5kJ/mol)+2(-241.8kJ/mol)-(-1940.9kJ/mol)\\\\\Delta H_{f,C_3H_4}=276.8kJ/mol[/tex]
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Sally does the work in 2.3 hours and Pete does 2.5
How many moles of water can be formed from 0.57 moles of hydrogen gas?
Answer:
0.57 water
Explanation:
To solve this problem, we need to write the reaction expression first.
The reactants are oxygen gas and hydrogen gas.
They react to give a product of water
2H₂ + O₂ → 2 H₂O
Given that;
Number of moles of hydrogen gas = 0.57moles
From the balanced reaction expression;
2 moles of hydrogen gas produces 2 moles of water
So;
0.57mole of hydrogen gas will also produce 0.57 water
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.In Part III, the methyl orange indicator is used to monitor the equilibrium shifts of the acetic acid/acetate ion system. The methyl orange equilibrium established with water is Hmo(aq)(orange-red) H2O(l) H3O (aq) mo-(aq)(yellow). You compared the color of the solutions in three test tubes that initially contained 3 mL of 0.1 M acetic acid and a few drops of methyl orange indicator. In the first test tube, you added 1.0 M NaC2H3O2 drop wise. What color change was observed and what did this color change indicate about the shift in the methyl orange equilibrium
Answer:
See explanation
Explanation:
Let us look at the situation closely, the undissociated Hmo is red in colour while the mo^- is yellow in colour.
This means that an acidic solution will appear red while a basic solution will appear yellow in colour.
NaC2H3O2 is a basic salt. When it is introduced, the acetate ion pulls a proton from water forming CH3COOH. CH3COOH is a weak acid and largely does not dissociate, it means that the undissociated acid remains in the solution leaving only the OH^- ions floating around thereby making the solution basic.
The colour of the system now changes to yellow.
Consider the equilibrium;
CH3COO^-(aq) + H2O(l) ------> CH3COOH(aq) + OH^-
Addition of NaC2H3O2 causes the equilibrium of this system to shift to the right.
The methyl orange water equilibrium also shifts towards the position where more mo^-(yellow) is produced.
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
water is a unique material in that the density of the solid is lower than the density of the liquid (which is why ice forms at the top of a pond and why ice floats in our drinks). if the density for ice at 0C is .917g/mL and the density for water at 0C is .999 g/mL, what is the calculated free space (as %) for each of these materials. you will need to estimate the volume of water as the sum of 2 H atoms and 1 O atom with radii 37 and 66 pm respectively. note that you will also have to assume a quantity of water to perform this exercise
Answer:
% Free space in water = [tex]\frac{9.945* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.45%
% Free space in ice = [tex]\frac{9.98* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.8%
Explanation:
As given ,
Density for ice at 0⁰C = 0.917 g/ml
Density for water at 0⁰C = 0.999 g/ml
Radii of H atoms = 37 pm
Radii of O atoms = 66 pm
Now,
Consider 1 ml of water = 1 cm²
As , we know that mass of water in 1 cm² = 0.999 g
Moles of water = [tex]\frac{0.999}{18} = 0.056[/tex]
Volume of H₂O = 1.624×[tex]10^{-31}[/tex] m²
Now,
Volume occupied by water = 0.056×6.022×[tex]10^{23}[/tex]× 1.624×[tex]10^{-31}[/tex] m²
= 5.48×[tex]10^{-9}[/tex] m²
⇒Volume occupied by water = 5.48×[tex]10^{-9}[/tex] m²
Now,
Free space = 1×[tex]10^{-6}[/tex] - 5.48×[tex]10^{-9}[/tex] = 9.95×[tex]10^{-7}[/tex] m²
% Free space = [tex]\frac{9.945* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.45%
Now,
Consider 1 ml of ice = 1 cm²
S.I unit of ice = 1×[tex]10^{-6}[/tex] m²
As , we know that mass of water in 1×[tex]10^{-6}[/tex] m² = 0.917 g
Moles of ice = [tex]\frac{0.917}{18} = 0.012[/tex]
Volume of H₂O = 6.022×[tex]10^{23}[/tex] ×0.012
Volume of ice unit = [tex]\frac{4}{3} \pi (37*10^{-12})^{3} *2 + \frac{4}{3} \pi (66*10^{-12})^{3} = 1.624*10^{-31}m^{3}[/tex]
Now,
Volume occupied by water = 0.012×6.022×[tex]10^{23}[/tex]× 1.624×[tex]10^{-31}[/tex] m²
= 1.17×[tex]10^{-9}[/tex] m²
⇒Volume occupied by water = 1.17×[tex]10^{-9}[/tex] m²
Now,
Free space = 1×[tex]10^{-6}[/tex] - 1.17×[tex]10^{-9}[/tex] = 9.98×[tex]10^{-7}[/tex] m²
% Free space = [tex]\frac{9.98* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.8%
Question 6 / 20
Which statement is always true about conservation of matter?
A. The mass of a system does not change during a chemical reaction
B. If a solid forms, the mass of a system increases
C. If a gas forms, the mass of a system decreases
D. The mass of a system changes when a substance changes from liquid to gas, but it does not change in
a chemical reaction
Select an answer
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Answer:
i gussss D is the answer may be
Answer:
A. The mass of a system does not change during a chemical reaction
Explanation:
Correct Answer
calculate the number of atoms in 0.25 mole of uranium.
Answer: 0.25 mol × (6.02214 × 1023 /mol) = 1.5 × 10
Explanation: Hope that helps
Answer the given question: use Chapter 1 of notebook
How many formula units are there in 3.20x 102 moles of LICI? (2pts.)
Conversion factor: 1 mole LICI=
_formula of LICI
Students, draw anywhere on this slide!
Answer:
1.93 x 10²⁶ formula units
Explanation:
Given parameters:
Number of moles of LiCl = 3.2 x 10² moles = 320moles
Unknown:
Number of formula units in this compound = ?
Solution:
The mole is used a reference to determine the number of substances matters contain.
A mole contains the Avogadro's number of particles.
So;
1 mole of a substance contains 6.02 x 10²³ formula units;
320 moles of LiCl will contain 320 x 6.02 x 10²³ = 1.93 x 10²⁶ formula units
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
What is aspartame? EXPLAIN
Answer:
it's an artificial non-saccharide sweetener 200 times sweeter than sucrose, and is commonly used as a sugar substitute in foods and beverages. it's a methyl ester of the aspartic acid/phenylalanine dipeptide with the trade names NutraSweet, Equal, and Canderel
Explanation:
Answer:
Aspartame is some type of very sweet substance that is used as an artificial sweetener, and chiefly in low-calorie products. It is a derivative of aspartic acid and phenylalanine.
Explanation:
Use what you have learned to match the parts of the
Someone help!!!!FAST
sentences.
The mantle
is both solid and molten.
The core
is the outermost layer.
The part that includes land and water
is called the crust.
The crust
is under the crust.
Answer:
the crust is the outermost layer
Explanation:
the mantle is under the crust, the core is the innermost layer
land and water.is for crust-mantle. contain semi-molten iron and nickel please make the question clear
Answer:
answer in picture
Explanation:
Suppose that you are given a mixture of proteins with their properties provided in the following chart.
Isoelectric point PI Molecular weight
Protein A 4.1 80
Protein B 9.0 81
Protein C 8.8 37
Protein D 3.9 172
Choose one combination of techniques that can be used to isolate Protein B from Proteins A, C, and D.
a. gel filtration chromatography and ultracentrifugation
b. dialysis and ultracentrifugation
c. dialysis and ion exchange chromatography
d. ion exchange chromatography and gel filtration chromatography
Answer:
The correct option is d. ion exchange chromatography and gel filtration chromatography
Explanation:
The mixture contains proteins with different isoelectric points and molecular weights. Ion exchange chromatography separates the proteins with different electric charges, which depend on the isoelectric point. At certain pH of the aqueous medium, the proteins will have a certain electric charge and they will be retained differently in the stationary phase. Proteins A and D have similar isoelectric points (around 4.0) and maybe they cannot be efficiently separated by this method; the same occurs with protein B and C (with an isoelectric point around 9.0). To separate proteins A from D and protein B from C, it could be used gel filtration chromatography. This separation method is based on differences in molecular weights. So, at the end of the process, we will obtain the proteins A, B, C, D separated one from each other.
Is caffeine additive?
Explain
Answer:yes anything can be addictive
Explanation:
Answer:
While caffeine produces a small rise in dopamine, it does not cause the large surge that unbalances the reward circuits in the brain and is necessary for an addiction. So even though the word “addiction” is often used casually, caffeine is not addictive (scientifically speaking).
What is the value of 4.698 after rounding it down to 3 significant figures?
Please help with whatever this is and go in number order
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.
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]
What are the correct products for the following reaction? ---->
K2SO4 + MgF2 ---->
Question 3 options:
2KF + MgSO4
F2SO4 + K2Mg
No reaction will occur
K2SO4 + F2Mg
Answer:
2KF+MgSO4
Explanation:
The correct product of the reaction above is 2KF + MgSO4.
What is a chemical reaction?A chemical reaction is a reaction in which the reactants or reacting substances react or combine together to produce the products.
Therefore, The correct product of the reaction above is 2KF + MgSO4.
Learn more about chemical reactions below.
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Explain what would happen to the air temperature at Riverdale School over the course of the
day if the groundwater system were used.
Answer:
Air temperature increases.
Explanation:
The air temperature at Riverdale School increases if the groundwater system were used because this system uses very huge amount of water than the other system. By using more molecules having the same temperature, the thing with more molecules has more total kinetic energy or thermal energy than the thing with fewer molecules so that's why air temperature of the school is increases.
An atom has 81 electrons, 84 neutrons, and 82 protons. What element is this atom?
Answer:
Lead
Explanation:
The subatomic particles within an atom can be used to know the atom or element given.
Of particular interest is the number of protons within the atom.
The periodic table is based on the atomic number of atoms. This atomic number is the number of protons within an atomic space.
So; If we know the number of protons within an atom, we can know the element.
The number of protons given is 82, the element is therefore lead.
Answer:
The atomic number of polonium is 84. The atomic number lead is 82.
Explanation:
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:
1. How many molecular orbitals can be built from the valence shell orbitals in O2?
Answer:
Atomic oxygen has 6 valence electrons and 4 valence orbitals (2s, 2px, 2py, and 2pz). We can draw a Lewis structure of molecular oxygen with a double bond between the oxygen atoms and 2 non-bonding pairs of electrons on each atom.
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
what divided by 700000 equals 4
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
15.0 g of Fe and 25.0 g of sand are added to 250.0 g of water. a. Determine the percent mass of Fe, sand, and water in the mixture. b. Create a flow chart illustrating how you could separate each of the mixture’s components. c. Explain which step of the separation is likely to have the highest amount of error.
Answer:
A. percentage mass of iron = 5.17%
percentage mass of sand = 8.62%
percentage mass of water = 86.205%
B. (Iron + sand + water) -------> ( iron + sand) ------> sand
C. The step of separation of iron and sand
Explanation:
A. Percentage mass of the mixtures:
Total mass of mixture = (15.0 + 25.0 + 250.0) g =290.0 g
percentage mass of iron = 15/290 * 100% = 5.17%
percentage mass of sand = 25/290 * 100% = 8.62%
percentage mass of water = 250/290 * 100% = 86.205%
B. Flow chart of separation procedure
(Iron + sand + water) -------> separation by filtration using filter paper and funnel to remove water --------> ( iron + sand) -----------> separation using magnet to remove iron ------> sand
C. The step of separation of iron and sand by magnetization of iron will have the highest amount of error because during the process, some iron particles may not readily be attracted to the magnet as they may have become interlaced in-between sand grains. Also, some sand particle may also be attracted to the magnet as they are are borne on iron particles.
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.
According to the Michaelis-Menten equation, when an enzyme is combined with a substrate of concentration s (in millimolars), the reaction rate (in micromolars/min) is
Answer:
The answer is "A"
Explanation:
Please find the complete question in the attachment file.
[tex]\to R(s)= \frac{As}{K+s}[/tex]
when the s in the approach, that is infinity R(s) tends
[tex]\to \frac{A}{\frac{K}{s}+1} \\\\ \to\frac{A}{0+1} \\\\ \to\frac{A}{1} \\\\ \to A[/tex]
2. Each cart below is pushed across a room with the same amount of force. Which cart will result in the greatest change in speed?
A )A 15 kg cart being pushed with a 200 N force
B ) A25 kg box being pushed with a 200 N force
C )A 45 kg cart being pushed with a 200 N force
D )A 35 kg box being pushed with a 200 N force
Answer: A 15 kg cart being pushed with a 200 N force.
Explanation:
The 15 kg cart is the lightest, so it has the least amount of friction on the ground.
The cart that will result in the greatest change in speed is the cart with a mass of 15 Kg
The correct answer to the question is Option (A) A 15 kg cart being pushed with a 200 N force
Acceleration is defined as the change in velocity of an object with time.
Acceleration is also related to force and mass according to the following equation:
Acceleration (a) = Force (F) / mass (m)
a = F / m
To answer the question given above, we shall determine the acceleration of the cart in each option.For Option A:
Mass (m) = 15 Kg
Force (F) = 200 N
Acceleration (a) =?a = F / m
a = 200 / 15
a = 13.33 m/s²For Option B:
Mass (m) = 25 Kg
Force (F) = 200 N
Acceleration (a) =?a = F / m
a = 200 / 25
a = 8 m/s²For Option C:
Mass (m) = 45 Kg
Force (F) = 200 N
Acceleration (a) =?
a = F / m
a = 200 / 45
a = 4.44 m/s²For Option D:
Mass (m) = 35 Kg
Force (F) = 200 N
Acceleration (a) =?a = F / m
a = 200 / 35
a = 5.51 m/s²From the illustrations made above, we can see that the cart with a mass of 15 Kg has the greatest acceleration (i.e change in speed)
Therefore, the correct answer to the question is Option (A) A 15 kg cart being pushed with a 200 N force
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