Answer:
Answer if yourself Kempner student.
Explanation:
xD
The number of atoms in exactly 12 grams of carbon-12 is called
The number of atoms which are present exactly in 12 grams of carbon-12 is called Avogadro's number.
What is Avogadro's number?Avogadro's number is the number of atoms which are present in 1 mole of any substance and it is equal to 6.022×10²³.
And moles will be calculated as:
n = W/M, whereW = given massM = molar massMoles of Carbon-12 = 12g / 12g/mol = 1mole
In 1 mole of Carbon-12 = 6.022×10²³ atoms are present.
Hence, the number of atoms in exactly 12 grams of carbon-12 is called Avogadro's number.
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Calculate the pH of a solution having the following ion concentrations at 298 K. [H+] = 4.6 × 10^-2 M
Answer:
The pH of the solution is 1.34, being an acidic pH.
Explanation:
pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance. The acronym pH stands for hydrogen potential.
The pH scale ranges from 0 to 14. Values less than 7 indicate the acidity range and those greater than 7 indicate alkalinity or basicity. Value 7 is considered neutral. Mathematically, pH is the negative logarithm of the molar concentration of hydrogen or proton ions (H⁺) or hydronium ions (H₃O⁺).
pH= - log [H⁺] = - log [H₃O⁺]
In this case, [H⁺]= 4.6*10⁻² M. Replacing:
pH= - log 4.6*10⁻²
Solving:
pH= 1.34
The pH of the solution is 1.34, being an acidic pH.
Complete the table:
Mass Solute Mass Solvent Mass Solution Mass Percent
2.65 g 26.0 g _____ _____
_____ 46.8 g _____ 4.0 %
1.68 g _____ 26.2 g _____
26.7 g _____ _____ 5.9 %
Answer:
1.
Mass solution = 28.65 g
Mass percent = 9.14 %
2.
Mass solute = 1.95 g
Mass solution = 48.75 g
3.
Mass solvent = 24.52 g
Mass percent = 6.41 %
4.
Mass solution = 476.8 g
Mass solvent =450.1 g
Explanation:
Hello,
In this case, we define the mass percent as:
[tex]\%m/m=\frac{m_{solute}}{m_{solute}+m_{solution}} *100\%[/tex]
Wherein we use the mass of the solute and the mass of the solvent in order to compute it, thus, for each case we have:
1.
Mass solution: 2.65 g + 26.0 g = 28.65 g
Mass percent: 2.62 g / (2.65 g + 26.0 g) x 100% = 9.14 %
2.
Mass solute: 4.0 % x 46.8 g / (1 - 4.0 %) = 1.95 g
Mass solution: 1.95 g + 46.8 g = 48.75 g
3.
Mass solvent: 26.2 g - 1.68 g = 24.52 g
Mass percent: 1.68 g / (1.68 g + 24.52 g) x 100% = 6.41 %
4.
Mass solution: 26.7 g / 5.6 % = 476.8 g
Mass solvent: 476.8 g - 26.7 g =450.1 g
Best regards.
Answer:
20.9
Explanation:
What is the molarity of a solution containing 0.05 moles of solute in 0.25L of solution?
Answer:
0.2 M
Explanation:
The molarity is the number of moles per liter:
(0.05 moles)/(0.25 liter) = 0.2 moles/liter = 0.2 M
By means of a schematic diagram show how a bacteria cell applied to the region of a cowpea root can end up by becoming a nitrate ion which can be absorb by a subsequent crop.
Answer:
Nitrifying bacterium such as nitrosomonas or nitrobacter, whe applied to the soil, convert free ammonia or nitrogen to nitrates through oxidation. They are a group of aerobic bacteria playing an important role in the nitrogen cycle as producers of energy from inorganic source.
The schematic diagram attached summaries the action of such bacteria.
In the
Preparation of ethene from ethanol and
tetraoxosulphate (vi) acid, state
the concentration of the acid.
Answer:
The acid must be a concentrated acid
Explanation:
Ethene is prepared in the laboratory by heating ethanol with excess concentrated tetraoxosulphate VI acid at 170°C . The reactionoccursc in two stages;
1) when the ethanol and sulphuric acid are mixed in a ratio of 1:2, ethyl hydrogentetraoxosulpate VI is formed
2) The compound formed in the first step is heated in the presence of excess concentrated sulphuric acid to give ethene and sulphuric acid.
The overall reaction can be perceived as the dehydration of ethanol. The gas produced (ethene) is usually passed through sodium hydroxide solution to remove any gaseous impurities present.
concentrated sulphuric acid is used in this process since it is a good dehydrating agent.
What diffuses faster: a gas sample into a vacuum container, or a gas sample into an air filled container?
Answer:
A gas sample into a vacuum diffuses faster than a gas sample into an air-filled container.
Explanation:
Diffusion
When a gas is introduced into a closed space, the molecules of the gas move freely and spread throughout the closed space.
The gas molecules tend to move from higher concentration to lower concentration area so that the concentration of gas throughout the closed space comes in equilibrium. This happens because higher concentration spaces have a greater number of gas molecules and vice-versa. In other words, gas molecules move towards the spaces having less concentration, i.e., they have a smaller number of gas molecules, and hence, can accommodate additional gas molecules.
This process of dispersion of gas molecules, as a result of difference in concentration, is called diffusion. The speed of diffusion is affected by the collisions suffered by the gas molecules.
When the molecules of gas disperse in any space, they have a tendency to travel in a straight line. In this process, they hit the molecules of other gases in the same space which causes a decrease in the speed of the molecules of gas hence, slowing the process of dispersion or diffusion.
Diffusion in air-filled container
When a gas is introduced into a closed container which is already filled with air, the molecules of the newly-introduced gas, as per their tendency, tend to move throughout the closed container irrespective of the concentration gradient.
Diffusion in a vacuum container
Whereas, in vacuum, the molecules of the introduced gas do not face any collisions with any molecules of other gas. The molecules of gas move freely until they collide with the sides of the container. The only collision occurring in a vacuum container is when the molecules hit the containers. Hence, gas diffusion takes place faster in a closed container having vacuum than a closed container which is already filled with air.
Base your answers on the graph below, which represents uniform cooling of a sample of a pure substance, starting as a gas. The boiling point of the substance is
Answer:
120
Explanation:
Because it starts as gas at from A to B, B to C is gas and liquid equilibrium, so in order to go to boiling point (point where it goes from liquid to gas) it happens at 120 because after that you see that steep slope which represents the gas being formed.
The transition from liquid to gas, or the boiling point, occurs at 120 because after that you see that steep slope, which symbolizes the gas being formed. This is because the transition from liquid to gas, or the boiling point, occurs at 120 because it starts as a gas at A to B, B to C is gas and liquid equilibrium.
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 material. A liquid's boiling point changes according on the atmospheric pressure in the area.
A cooling curve is a line graph that depicts the transition of matter from one phase to another, usually from a liquid or gas to a solid. Time is an independent variable (X-axis), while temperature is a dependent variable (Y-axis).
Thus, the boiling point of the substance is 120° c.
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Question 1 When of alanine are dissolved in of a certain mystery liquid , the freezing point of the solution is lower than the freezing point of pure . On the other hand, when of iron(III) chloride are dissolved in the same mass of , the freezing point of the solution is lower than the freezing point of pure . Calculate the van't Hoff factor for iron(III) chloride in . Be sure your answer has a unit symbol, if necessary, and round your answer to significant digits.
Answer:
See explaination
Explanation:
please kindly see attachment for the step by step solution of the given problem
HURRRYYYY
Based on the chemical equation, use the drop-down menu to choose the coefficients that will balance the chemical equation:
()CaSO4 → ()O2 + ()CAS
Answer:
1, 2, 1
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
Answer:
1,2,1
Explanation:
just did the assigment
CHEM EXPERT NEEDED***
A volume of 150.0 mL of H2O is initially at 24.00 °C. A chilled steel rod at 2.50 °C is placed in the water and the final temperature of the system is 21.20 °C.
Specific heat of water = 4.184 J/(g⋅∘C) and the specific heat of steel = 0.452 J/(g⋅∘C)
Write the equation and calculate the mass of the rod.
Answer:
1. m₁C₁ΔT₁ + m₂C₂ΔT₂ = 0
2. 207 g
Explanation:
This is a problem in calorimetry — the measurement of the quantities of heat that flow from one object to another.
It is based on the Law of Conservation of Energy — Energy can be transformed from one type to another, but it cannot be destroyed or created.
If heat flows out of one object, the same amount of heat must flow into another object.
Since there is no change in total energy,
Heat₁ + heat₂ + heat₃+ … = 0
The symbol for the quantity of heat transferred is q, so we can rewrite the word equation as
q₁ + q₂ + q₃ + … = 0
The formula for the heat absorbed or released by an object is
q = mCΔT, where
m = the mass of the sample
C = the specific heat capacity of the sample, and
ΔT = T_f - T_i = the change in temperature
1. Equation
There are two heat flows in this problem,
Heat from steel rod + heat absorbed by water = 0
q₁ + q₂ = 0
m₁C₁ΔT₁ + m₂C₂ΔT₂ = 0
2. Data:
m₁ = ?; C₁ = 0.452 J°C⁻¹g⁻¹;T_f = 21.20 °C; T_i = 2.50 °C
V₂ = 150.0 mL; C₂ = 4.184 J°C⁻¹g⁻¹; T_f = 21.20 °C; T_i = 24.00 °C
3. Calculations
(a) m₂
The density of water is 0.9982 g/mL, so
m₂ = 150.0 mL × 0.9982 g/mL = 149.7 g
(b) Temperature changes
[tex]\Delta T_{1} = T_{\text{f}} - T_{\text{i}} = 21.20 \, ^{\circ}\text{C} - 2.50 \, ^{\circ}\text{C} = 18.70 \, ^{\circ}\text{C}\\\Delta T_{2} = T_{\text{f}} - T_{\text{i}} = 21.20 \, ^{\circ}\text{C} - 24.00 \, ^{\circ}\text{C} = -2.80 \, ^{\circ}\text{C}[/tex]
(c) q₁
q₁ = m₁C₁ΔT₁ = m₁ × 0.452 J°C⁻¹g⁻¹ × 18.70 °C = 8.452m₁ J·g⁻¹
(d) q₂
q₂ = m₂C₂ΔT₂ = 149.7 g × 4.184 J°C⁻¹g⁻¹ × (-2.80 °C) = -1754 J
(e) m₁
[tex]\begin{array}{rcl}q_{1} + q_{2} & = & 0\\8.452m_{1} \, \text{J}\cdot\text{g}^{-1} + (-\text{1754 J}) & = & 0\\8.452m_{1}\,\text{g}^{-1} - 1764 &=& 0\\m_{1} & = & \dfrac{1764}{8.452 \,\text{g}^{-1}}\\\\ & = & \textbf{207 g}\\\end{array}\\\text{ The mass of the steel rod is $\large \boxed{\textbf{207 g}}$}[/tex]
In a solution at 25 degrees Celsius the H is 3.5 x 10^-6 M. What is the OH
Answer:
Explanation:
[ H⁺] = 3.5 x 10⁻⁶ M .
[ H⁺] [ OH⁻] = 10⁻¹⁴
[ OH⁻] x 3.5 x 10⁻⁶ = 10⁻¹⁴
[ OH⁻] = 2.857 x 10⁻⁹ M .
Identify the conjugate base in each pairs
1)RCOOH. RCOO
2)H2PO+. H2PO4
3)RNH2.RNH3+
4)H2CO3.HCO3-
Answer: 1) [tex]RCOO^-[/tex]
2) [tex]H_2PO_4^-[/tex]
3) [tex]RNH_2[/tex]
4) [tex]HCO_3^-[/tex]
Explanation:
According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.
1) [tex]RCOOH\rightarrow RCOO^-+H^+[/tex]
Here, [tex]RCOOH[/tex] is loosing a proton, thus it is considered as an acid and after losing a proton, it forms [tex]RCOO^-[/tex] which is a conjugate base.
2) [tex]H_3PO_4\rightarrow H_2PO_4^-+H^+[/tex]
Here, [tex]H_3PO_4[/tex] is loosing a proton, thus it is considered as an acid and after losing a proton, it forms [tex]H_2PO_4^-[/tex] which is a conjugate base.
3) [tex]RNH_3^+\rightarrow RNH_2+H^+[/tex]
Here, [tex]RNH_3^+[/tex] is loosing a proton, thus it is considered as an acid and after losing a proton, it forms [tex]RNH_2[/tex] which is a conjugate base.
4) [tex]H_2CO_3\rightarrow HCO_3^-+H^+[/tex]
Here, [tex]H_2CO_3[/tex] is loosing a proton, thus it is considered as an acid and after losing a proton, it forms [tex]HCO_3^-[/tex] which is a conjugate base.
calculate the number of chloride ions in 6.8 g of zinc chloride
Answer:
The correct answer is 0.300 * 10^23 ions.
Explanation:
Based on the given question, there is a need to find the number of chloride ions in the mentioned 6.8 grams of zinc chloride compound.
The moles of zinc chloride (ZnCl2) is,
= mass of zinc + 2 mass of chlorine
= 65.38 + 2 (35.45)
=65.38 + 70.90
= 136.28 grams (The molecular mass of zinc is 65.38 and the molecular mass of chlorine is 35.45)
Thus, 136.28 g of ZnCl2 contains 70.90 grams of chlorine
Therefore, 6.8 grams of ZnCl2 will comprise = (70.90/136.28) * 6.8
= 3.537 g of chlorine
70.90 g of Cl comprise 6.022*10^23 chlorine, thus, 3.537 g of Cl will comprise (6.022*10^23/70.90) * 3.537
= 0.300 * 10^23 ions of chlorine.
How could weathering by release of pressure affect the amount of weathering by freezing and thawing?
The amount of weathering by the freezing and thawing process of water is the most effective weathering.
What is weathering?Weathering is a process in which breaking or dissolving of rocks and minerals present on the earth surface.
Freezing and thawing weathering is a kind of physical weathering in which water goes down to the pores of rock and gets freeze and expands and causes breaking of rocks.Release of pressure also result in the weathering of the underlying rocks.Weathering by the freezing effect of water causes more effect on the breaking as compare to the pressure release weathering.
Hence Freezing & thawing weathering is most powerful weathering.
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what structural units make up iconic solids
Answer:
the structural units are anions and cations bonded together by strong, non-directional ionic bonds
where does the chemical reaction take during photosynthesis
Answer:
in all green plants and most algae
We now consider three moles of ideal gas at the same initial state (3.0 L at 273 K). This time, we will first perform an isobaric compression, then an isothermal expansion to bring the gas to the final state with the same volume of 3.0 L, and at temperature 110 K. Hint (a) How much work (in J) is done on the gas during the isobaric compression? Wcompression = J (b) How much work (in J) is done on the gas during the isothermal expansion? Wexpansion = J
Answer:
Explanation:
check the image
a)
The workdone on the gas during during the isobaric compression
W = pΔV
= nRΔT
= 2 * 8.314 * (273-110)
=2710J
b) The workdone on the gas during during the isothermal expansion
[tex]W= nRT_fIn(\frac{V_f}{V_i} )\\\\2*8.314*110In\frac{110}{273} \\\\=-1662.6J[/tex]
Answer:
a) The work done during the isobaric compression is 4060.91 J.
b) The work done during the isothermal expansion is 2489.58 J.
Explanation:
a) Here we have two different processes. We calculate the work done during the isobaric compression using the following formula:
[tex] W= -P. (V₂ - V₁) [/tex]
Since the process is isobaric, the pressure is constant. First we need to find this value. In order to do that, we use the ideal gas equation:
[tex] p.V= n.R.T [/tex]
[tex] p= [n.R.T] ÷ V = [3 mol × 0.082 (L.atm÷mol.K) × 273 K] ÷ 3 L [/tex]
p = 22.39 atm
Now, we need to find V₂. We do this using Charles' law:
[tex] V₁/T₁ = V₂/T₂ [/tex]
[tex] V₂ = V₁/T₁ × T₂ = 3 L ÷ 273 K × 110 K [/tex]
V₂ = 1.21 L
Now we are in condition to calculate the work done during the isobaric compression:
[tex] W= -P. (V₂ - V₁) [/tex]
[tex] W= -22.39 atm. (1.21 - 3) L [/tex]
W= 40. 07 L.atm
We multiply this value by 101.325 to convert it to joules: W= 4060.91 J
b) To calculate the work done during the isothermal expansion, we use the following equation:
[tex] W = n.R.T. ln (V₂/V₁) [/tex]
[tex] W = 3 mol ×0.082 (L.atm/mol.K) × 110 K × ln (3L / 1.21 L) [/tex]
W= 24.57 L.atm
We convert this value to joules: W= 2489.58 J
if 84.9 grams of solid iron reacts with oxygen gas, how many molecules of oxygen will react
Answer:
Molecules of oxygen [tex]= 6.86 * 10^{23}[/tex]
Explanation:
The balanced equation of reaction between iron and oxygen is
4 Fe + 3 O2 → 2 Fe2O3
4 moles of iron react with 3 moles of oxygen.
Mass of one mole of iron is 55.845
number of iron moles in 84.9 grams of solid iron is equal to
[tex]\frac{84.9}{55.845} \\= 1.52[/tex]
Now 1 mole of iron will react with [tex]\frac{3}{4} = 0.75[/tex] mole of oxygen
Thus 1.52 moles of iron will react with [tex]0.75 * 1.52 = 1.14[/tex] moles of oxygen
Number of atoms of oxygen in 1.14 moles
[tex]1.14* 6.02 * 10^{23}\\[/tex]
[tex]= 6.86 * 10^{23}[/tex]
The British gold sovereign coin is an alloy of gold and copper having a total mass of 7.988 g, and is 22-karat gold.
(a) Find the mass of gold in the sovereign in kilograms using the fact that the number of karats = 24× (mass of gold)/ total mass.
(b) Calculate the volumes of gold and copper, respectively, used to manufacture the coin.
(c) Calculate the density of the British sovereign coin.
Answer:
(a) [tex]m_{gold}=7.322g[/tex]
(b)
[tex]V_{gold}=0.379cm^3[/tex]
[tex]V_{copper}=0.122cm^3[/tex]
(c) [tex]\rho _{coin}=15.94g/cm^3[/tex]
Explanation:
Hello,
(a) In this case, with the given formula we easily compute the mass of gold contained in the sovereign as shown below:
[tex]m_{gold}=\frac{m_{tota}*karats}{24}=\frac{7.988g*22}{24}=7.322g[/tex]
(b) Now, by knowing the density of gold and copper, 19.32 and 8.94 g/cm³ respectively, we compute each volume, by also knowing that the rest of the coin contains copper:
[tex]V_{gold}=\frac{m_{gold}}{\rho_{gold}} =\frac{7.322g}{19.32g/cm^3}=0.379cm^3[/tex]
[tex]m_{copper}=7.988g-7.322g=1.09g\\V_{copper}=\frac{m_{copper}}{\rho_{copper}}=\frac{1.09g}{8.94g/cm^3} \\\\V_{copper}=0.122cm^3[/tex]
(c) Finally, the volume is computed by dividing the total mass over the total volume containing both gold and copper:
[tex]\rho _{coin}=\frac{m_{total}}{V_{gold}+V_{copper}}=\frac{7.988 g}{0.379cm^3+0.122cm^3}\\ \\\rho _{coin}=15.94g/cm^3[/tex]
Best regards.
Answer:
a
The mass of gold is [tex]L = 7.322 *10^{-3} \ kg[/tex]
b
The volumes of gold and copper is [tex]V_g = 3.794 *10^{-7} \ m^3[/tex] , [tex]V_c = 7.426 *10^{-8} \ m^3[/tex]
c
The density of the British sovereign coin
[tex]\rho = 17.593*10^{3} \ kg/m^3[/tex]
Explanation:
From the question we are told that
The total mass of the gold is [tex]K = 7.988 \ g = 7.988 * 10^{-3} \ kg[/tex]
The karat of the British gold sovereign is [tex]z = 22[/tex]
Let the mass of gold in the alloy be L
Now we are told that
[tex]z = 24 * \frac{L}{K}[/tex]
substituting value
[tex]22 = 24 * \frac{L}{7.988 * 10^{-3}}[/tex]
So [tex]L = \frac{22}{24} * 7.899*10^{-3}[/tex]
[tex]L = 7.322 *10^{-3} \ kg[/tex]
The volume of the gold coin is mathematically represented as
[tex]V_g = \frac{L}{\rho_g }[/tex]
Where [tex]\rho_g[/tex] is the density of the gold which a constant with value
[tex]\rho_g = 19.3 *10^{3} \ kg /m^3[/tex]
So
[tex]V_g = \frac{7.322 *10^{-3}}{19.3 *10^{3} }[/tex]
[tex]V_g = 3.794 *10^{-7} \ m^3[/tex]
The mass of copper is mathematically evaluated as
[tex]m_c = K - L[/tex]
[tex]m_c = 7.988*10^{-3} - 7.322 *10^{-3}[/tex]
[tex]m_c = 6.657 *10^{-4} \ kg[/tex]
Volume of the copper is
[tex]V_c = \frac{m_c}{\rho_c}[/tex]
Where [tex]\rho_c[/tex] is the density of the copper which a constant with value
[tex]\rho_c = 8.92 * 10^{3} \ kg/m^3[/tex]
So
[tex]V_c = \frac{6.657 *10^{-4}}{8.92 *10^{3}}[/tex]
[tex]V_c = 7.426 *10^{-8} \ m^3[/tex]
The total volume of the British gold sovereign coin is \
[tex]V = V_g + V_c[/tex]
substituting values
[tex]V = 3.7939 *10^{-7} + 7.4626 *10^{-7}[/tex]
[tex]V = 4.54 *10^{-7} \ m^3[/tex]
The density of the British gold sovereign coin is
[tex]\rho = \frac{K}{V}[/tex]
substituting values
[tex]\rho = \frac{7.988 *10^{-3}}{4.54 *10^{-7}}[/tex]
[tex]\rho = 17.593*10^{3} \ kg/m^3[/tex]
For many purposes we can treat propane as an ideal gas at temperatures above its boiling point of . Suppose the temperature of a sample of propane gas is lowered from to , and at the same time the pressure is decreased by . Does the volume of the sample increase, decrease, or stay the same? increase decrease stays the same If you said the volume increases or decreases, calculate the percentage change in the volume. Round your answer to the nearest percent.
Answer:
See explaination
Explanation:
please kindly see attachment for the step by step solution of the given problem
Which of the following atoms is the smallest?
Be
Ne
O
Li
B
Answer:
Li
Explanation:
The element, Neon (Ne), is the smallest among the given elements
From the question,
We are to determine which of the given elements is the smallest.
The given elements are
Be - Beryllium
Ne - Neon
O - Oxygen
Li - Lithium
B - Boron
From the periodic table, we can observe that all of the given elements belong to period 2.
Using the trend of atomic size on the periodic table,
We know that, atomic size decreases across the period.
This means, the atomic sizes of the elements will decrease in the order
Li > Be > B > O > Ne
Hence, the element, Neon (Ne), is the smallest among the given elements
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Balance the equation below, using the smallest whole-number coefficients. ____Fe(s) + ____ O2(g) + ____ H2O(l) → ____Fe(OH)2(s)
Answer:
2Fe(s) + O₂(g) + 2H₂O(l) → 2Fe(OH)₂(s)
Explanation:
Balanced equation willl be:
[tex]2Fe(s) + O_2(g) + 2H_2O(l) - > 2Fe(OH)_2[/tex]
What is balance equation with example?A balanced chemical equation occurs when the number of the atoms involved in the reactants side is equal to the number of atoms in the products side. In this chemical reaction, nitrogen (N2) reacts with hydrogen (H) to produce ammonia (NH3). The reactants are nitrogen and hydrogen, and the product is ammonia.
What is the rule of balance?On a separate sheet of paper, make a claim in which you mathematically state the rule of balance - that is, the rule that one must use to determine if two weights placed on opposite sides of the fulcrum will balance each other.
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Some building materials contain small capsules filled with paraffin wax to improve the insulating properties of the materials. The melting and freezing of paraffin inside the capsules in the material helps to regulate temperature. Paraffin wax begins to melt at 37°C37°C.(a) While the wax is melting, is the net flow of thermal energy from the wax to the surroundings or from the surroundings to the wax? Justify your answer.(b) Calculate the amount of thermal energy, in kJkJ, that is required to melt 15.215.2 grams of solid paraffin wax when the temperature of the surroundings is above the melting point of paraffin. (The molar mass of paraffin is 282.62g/mol282.62g/mol, and its molar heat of fusion is 48.78kJ/mol)(c) When paraffin wax melts, its density decreases. Provide a particle-level explanation of this observation.
Answer:
(a)
From surrounding to wax
(b)
Q = 2.62 KJ
(c)
Density of a substance is defined as the no. of particles of the substance, that occur in a unit volume. So, when the substance melts, the inter-molecular attractive forces and bonds between molecules or atoms are weakened. This, increases the distance between the molecules or atoms. Hence, the no. of particles in a unit volume is decreased. As, a result of this, the density of the substance also decreases.
Explanation:
(a)
During the melting process, the solid material or substance requires energy, in order to break the bonds between its molecules or atoms.
Therefore, while the wax is melting, the net flow of thermal energy is from surrounding to the wax.
(b)
The amount of energy required to melt solid paraffin wax is given by the formula:
Q = nC
where,
Q = amount of energy
C = Molar Heat of Fusion = 48.78 KJ/mol
n = No. of Moles = Mass in gram/Molar Mass = (15.2 g)/(282.62 g/mol)
n = 0.0538 mol
Therefore,
Q = (0.0538 mol)(48.78 KJ/mol)
Q = 2.62 KJ
(c)
Density of a substance is defined as the no. of particles of the substance, that occur in a unit volume. So, when the substance melts, the inter-molecular attractive forces and bonds between molecules or atoms are weakened. This, increases the distance between the molecules or atoms. Hence, the no. of particles in a unit volume is decreased. As, a result of this, the density of the substance also decreases.
(a) During the melting of wax, the flow of thermal energy has been from the surroundings to the wax.
(b) The amount of heat requires for the melting of 15.215 grams of solid paraffin has been 2.62 kJ.
(c) The density decreases due to a decrease in the number of molecules per unit volume.
(a) Melting results in the conversion of solid-state to the liquid state. This step requires energy. Thus, the flow of energy has been from the surroundings to the wax.
(b) Amount of heat requires (Q) can be given by:
Q = nC
Where, n = moles of the sample, and C = heat of fusion
Moles of paraffin = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of paraffin = [tex]\rm \dfrac{15.215}{286.62}[/tex]
Moles of paraffin = 0.0538 moles
Q = 0.0538 [tex]\times[/tex] 48.78 kJ/mol
Q = 2.62 kJ.
The amount of heat requires for the melting of 15.215 grams of solid paraffin has been 2.62 kJ.
(c) The density has been the mass or number of particles present per unit volume. The melting of wax results in a weaker intermolecular force. The resulting liquid will have fewer molecules present in the unit volume.
Thus, the density decreases due to a decrease in the number of molecules per unit volume.
For more information about the heat of fusion, refer to the link:
https://brainly.com/question/14053504
Use the periodic table to correctly describe the arrangement of electrons in an oxygen atom. Check all of the
boxes that apply.
Answer:
second option and last option
Explanation:
Know how to do an electron configuration. This is correct because it adds up to 8 and is in the correct order.
All valence electrons are in the last shell. In this case, 2p is the last shell.
Answer:
It's the second and the second to last
Explanation:
What is the difference between a strong electrolyte and a weak electrolyte
Answer:
One will give you more energy and the other will make you tired!
Explanation:
Olivia, a Latina student, is told that she can check only two books out of the library at a time, but Leann, a white student, is told that she can check out as many books as she wants. The best way for a white person to help end this type of white privilege is to say:
A. that this difference in treatment should stop now .
B. that it's better than it used to be
C. that it's worse in other countries
D. that people of color are overly sensitive .
Answer:
a
Explanation:
the others are rude, and rather support this, while a helps to support the ending of white privlige
Answer:
A. Definitely!
Explanation:
If everyone says that in other country that's worst and let it go, racism will never stop! Saying that people of color are overly sensitive is also racist because everyone can be sensitive. There color of skin change nothing! They are humans like everyone and if they want to defend themself, they have the right! Racism still exist and it needs to stop after all these years of sufferance and pain. White people are not better that people of color. Everyone deserve to be equal. Thank you.
why do we need to standardize EDTA in determination of water hardness?
Answer:
a specific amount edta is added to a specific amount of distilled water
Explanation:
what is the mass of oxygen in 10g of water
Answer:
8.90g
Explanation:
2×O=2×16.00=32.00g
mass=0.278×32.00g=8.90g
At which electrade in a voltaic cell does redaction always occar?
Answer:cathode
Explanation:It is also known as the galvanic cell or electrochemical cell. In the voltaic cell, the oxidation occurs at an anode which is a negative electrode and the reduction occurs at the cathode which is a positive electrode.