What is the delta H when 72.0 grams H2O condenses at 100.00C?
Here are some constants that you MAY need.
specific heats heat of fusion heat of vaporization
H2O(s) = 2.1 J/g0C 6.01 kJ/mole 40.7 kJ/mole
H2O(L) = 4.18 J/g0C
H2O(g) = 1.7 J/g0C
2930 kJ
163 kJ
-163 kJ
-2930 kJ
Answer: The value of [tex]\Delta H[/tex] is -163 kJZ
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
We are given:
Given mass of water = 72.0 g
Molar mass of water = 18 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of water}=\frac{72.0g}{18g/mol}\\\\\text{Moles of water}=4mol[/tex]
Calculating the heat released for the condensation process:
[tex]\Delta H=n\times \Delta H_{(vap)}[/tex] ......(2)
where,
[tex]\Delta H[/tex] = amount of heat released
n = number of moles of water = 4 moles
[tex]\Delta H_{(vap)}[/tex] = specific heat of vaporization = -40.7 kJ/mol
Negative sign represents the amount of heat released.
Putting values in equation 2:
[tex]\Delta H=4mol\times (-40.7kJ/mol)=-163kJ[/tex]
Hence, the value of [tex]\Delta H[/tex] is -163 kJ
Matter takes up _____.
(a) Space and temperature
(b) Space and heat
(c) Space and mass
(d) Heat and temperature
Joelle is a manager at a construction company, and she is interested in the chemistry behind the materials they use. She has begun studying the materials used to fill walls. She knows that to keep the temperature inside a room steady the material must be a thermal insulator, and she predicts that materials should not be acidic or else they would dissolve too easily in water.
Which of these is a molecular ingredient that could be used in a wall-filling material ?
C27H36N2O10
Na6Ba6
NeNa
HCl
Answer:
a
Explanation:
A molecular ingredient that could be used in a wall-filling material is C₂₇H₃₆N₂O₁₀, is not a good thermal insulator, hence option A is correct.
The big molecule C₂₇H₃₆N₂O₁₀ is a poor thermal insulator. Since NeNa is a relatively reactive chemical, it would probably dissolve in water far too quickly. The acidic molecule HCl would dissolve far too quickly in water.
Not a good thermal insulator is C₂₇H₃₆N₂O₁₀. It is a big molecule composed of a lot of hydrogen atoms. Since hydrogen atoms are excellent heat conductors, they would be ineffective in stopping heat from passing through a material used to fill a wall.
Thus, the option (A) C₂₇H₃₆N₂O₁₀ is correct.
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1. In 1996 a meteor crashed into the Earth near Steelsville, Ontario. The resulting meteorite was found to contain 5,790 g of Molybdenum Chloride having a formula of Mo2Cl9. How many molecules of Mo2Cl9 are present in the 5,790 g meteor?
Answer:
6.38×10²¹ molecules
Explanation:
Formula for molybdenum chloride is:
Mo₂Cl₁₀
Molar mass is : (Molar mass for Mo) . 2 + (Molar mass for Cl) . 10
95.94 . 2 + 35.45 . 10 = 546.38 g/mol
We determine moles that are contained in 5.790 g of Mo₂Cl₁₀
5.790 g . 1 mol /546.38 g = 0.0106 moles
We count the molecules: 0.0106 mol . 6.02×10²³ molecules / mol =
6.38×10²¹ molecules
Remember that 6.02×10²³ is also called Avogadro's number (NA) which is the number of particles of anything, that are contained in 1 mol.
Which of the following best describes an electron transition?
A. An electron gains or loses energy and moves between continuous
energy levels.
B. An electron gains or loses charge and changes into a proton or a
neutron.
C. An electron gains or loses energy and moves between quantized
energy levels.
D. An atom gains or loses an electron and becomes an ion.
Answer:
A. An electron gains or loses energy and moves between continuous
energy levels.
What happens when an unstable nucleus undergoes radioactive decay?
A. Electrons change energy levels to balance the nucleus.
B. Energy is absorbed by the nucleus to make it more stable.
O C. Particles or electromagnetic radiation are emitted.
D. The nucleus increases in mass through radioactive decay.
how does evelyn hear music?
Which of these is true about a pH meter?
It is inexpensive to use.
It measures pH indirectly.
It does not require calibration.
It can be used in any acid-base titration.
Answer:
That is, a pH meter is useful in detecting or knowing the acidity (due to ions) or alkalinity (due to ions) of a solution. Thus, we can conclude that out of the given options it is true about a pH meter that it can be used in any acid-base titration
Answer: D. It can be used in any acid-base titration.
Explanation:
A carbon atom that is surrounded by four hydrogen atoms has a _____ molecular geometry. This geometry results from the arrangement of the _____ hybrid orbitals around the carbon atom. They are formed when the s-orbital and ______ -orbitals mix, or hybridize.
Answer:
Tetrahedral, sp3, p
Explanation:
C has 4 bonds and hence its tetrahedral shape with 109.5 degrees. since there are 4 bonds, it is sp3
Answer:
A carbon atom that is surrounded by four hydrogen atoms has a
✔ tetrahedral
molecular geometry.
This geometry results from the arrangement of the
✔ four sp3
hybrid orbitals around the carbon atom.
They are formed when the s-orbital and
✔ three p
-orbitals mix, or hybridize.
Explanation:
Use mathematics to prove that the 5.50 grams of salicylic acid (C7H6O3) used in this experiment is equal to 0.04 mol.
Answer:
Please find the answer to the question below
Explanation:
In chemistry, the following mathematical formula is used to calculate the number of moles contained by a substance:
mole = mass of substance (g)/molar mass of substance (g/mol)
Molar mass of salicylic acid (C7H6O3) = 12(7) + 1(6) + 16(3)
= 84 + 6 + 48
= 138g/mol
Mass = 5.50grams
mole = 5.5/138
mole = 0.039
Approximately, the number of moles of 5.5grams of salicylic acid is 0.04moles. This is in accordance with the mole value (0.04) given in this question.
Por qué razón se fomenta la inmigración Europea?
Hola aquí va la respuesta!
Se fomentó la inmigración europea porque la economía no era buena y vinieron a Paraguay para mejorar su situación.
Hola aquí va la respuesta!
Se fomentó la inmigración europea porque la economía no era buena y vinieron a Paraguay para mejorar su situación.
Given the structural formula: This compound is classified as an
Answer:
A.) aldehyde is the answer
From the given structural formula, the compound is ethanamide and thus, belongs to the group of amides. Thus, the correct option is B.
Amide is a functional group of organic compounds having an acyl group (R-C=O) linked to amine group (-NR¹R² where R¹ and R² are hydrogen atoms or alkyl groups). The amide functional group is given as -CON= (not double bond with N, but two distinct single bonds).
Amides can be classified into the following types depending on the moiety attached to nitrogen other than the carbonyl carbon:
1. Primary amides - amide in which the nitrogen atoms is attached to two hydrogen atoms
2. Secondary amides - in which the nitrogen atom is attached to one hydrogen and one alkyl group.
3. Tertiary amides - in which the nitrogen atom is attached to two alkyl groups.
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How much heat is required to raise the temperature of 16.0 grams H2O from 5.000C to 75.00C? Below is a list of constants.
specific heat for H2O(s) = 2.1 J/g0C
specific heat for H2O(L) = 4.18 J/g0C
specific heat for H2O(g) = 1.7 J/g0C
\bigtriangleup H△Hvap = 40.7 kJ/mol
\bigtriangleup H△Hfus = 6.01 kJ/mol
5.34 J
260 J
4680 J
2350 J
Answer:
The amount of heat required is 4681.6 J.
Explanation:
mass, m = 16 g = 0.016 kg
initial temperature, T = 5 C
final temperature, T' = 75 C
specific heat, c = 4.18 J/g C
The amount of heat required is
H = m c (T'- T)
H = 16 x 4.18 x (75 - 5)
H = 4681.6 J
If the pH = 6.5, what is the [H+]? *
3.16 x 10-7
3.16 x 10-6
O
3.16 x 10-5
Answer:
Key Concepts
The hydrogen ion concentration in a solution, [H+], in mol L-1, can be calculated if the pH of the solution is known.
pH is defined as the negative logarithm (to base 10) of the hydrogen ion concentration in mol L-1 pH = -log10[H+] ...
[H+] in mol L-1 can be calculated using the equation (formula): [H+] = 10-pH
More items...
Explanation:
Answer:
[tex]pH = - log[H {}^{ + } ] \\ 6.5 = - log[H {}^{ + } ] \\ [H {}^{ + } ] = {10}^{ - 6.5} \\ [H {}^{ + } ] = 3.16 \times {10}^{ - 7} \: mol {dm}^{ - 3} [/tex]
Use the equation below to answer the following question
2NaHCO3(aq) + Ca(H2PO4)2 (aq) → Na2HPO4 (aq) + CaHPO4 (aq) + 2002 (8) + 2H20 (0)
The theoretical yield of CHPO, is 10 g. If 8 g of CaHPO4 are produced from the reaction shown above, what is the percent yield of CHPO ?
Answer:
Percent Yield = 80%
Explanation:
Percent yield of a reaction is defined as one hundred times the ratio between the actual yield and the theoretical yield. That is:
Percent yield = Actual Yield / Theoretical Yield * 100
Where theoretical yield of CaHPO4 is 10g and actual yield is 8g
Replacing:
Percent yield = 8g / 10g * 100
Percent Yield = 80%22)When iron rusts in air, iron(III) oxide is produced. How many moles of oxygen will react
with 2.4 mol of iron ?
4Fe(s) + 3O2(g) → 2Fe2O3(s)
A)1.2 mol
B)1.8 mol
C)2.4 mol
D)3.2 mol
E)4.8 mol
show work
Answer:
B
Explanation:
)When iron rusts in air, iron(III) oxide is produced. How many moles of oxygen will react
with 2.4 mol of iron ?
B)1.8 mol
Calculate the total amount of energy required in calories to convert 50.0 g of ice at 0.00 degrees Celsius to steam at 100. degrees Celsius.
Specific heat capacity of water is 1.00 cal/g OC
Hfusion = 80 cal/g OC and Hvap = 540 cal/g OC
Write the complete equation you will use. 1 point
Substitute the values in the equation in step 1. 1 point
Report the math answer with 3 sig figs and the correct unit. 1 point
Answer:
HFusion*mass + Spec.Heat*mass*ΔT + HVap*mass
80cal/g*50.0g + 1.00cal/g°C*50.0g*(100°C-0°C) + 540cal/g*50g
3.60x10⁵cal
Explanation:
Using the HFusion we can find the heat needed to convert the ice to liquid water.
With specific heat capacity we can find the heat needed to increase the temperature of water from 0 to 100°C.
With HVap we can find the heat to convert the liquid water into steam.
The equations are:
HFusion*mass + Spec.Heat*mass*ΔT + HVap*massComputing the values:
80cal/g*50.0g + 1.00cal/g°C*50.0g*(100°C-0°C) + 540cal/g*50g36000cal =
3.60x10⁵calWhat is the pH of a solution?
O A. A measure of the strength of the acid
B. A measure of the buffering ability of the solution
O c. A measure of the hydrogen gas concentration
O D. A measure of the acidity of the solution
Answer:
D. A measure of the acidity of the solution
Explanation:
pH is a measure of how acidic or basic a solution is, and is measured on a scale from 0-14, where 7 is neutral, anything less than 7 is acidic, and anything more than 7 is basic.
The metric system is also known as the
Answer:
THE answer is all of above
Explanation:
A + 2 B + 4 C → products is known to be second order in A, first order in B and independent of the concentration of C. What is the value of the rate constant for this reaction if its rate is 0.783 M · s−1 when [A] = 5.00 M, [B] = 7.00 M, and [C] = 3.00 M? −2 −1 Answerinunitsof M ·s .
Answer:
4.47 × 10⁻³ M⁻² s⁻¹
Explanation:
Let's consider the following generic equation.
A + 2 B + 4 C → products
This reaction is known to be second order in A, first order in B and independent of the concentration of C (zero order in C). The rate law is:
rate = k × [A]² × [B] × [C]⁰
rate = k × [A]² × [B]
where k is the rate constant
When the rate is 0.783 M/s, [A] = 5.00 M, [B] = 7.00 M, and [C] = 3.00 M, the rate constant is:
k = rate / [A]² × [B]
k = 0.783 M/s / (5.00)² × (7.00) = 4.47 × 10⁻³ M⁻² s⁻¹
Which of the following correctly ranks the following bonds in order from most to least polar?
C-H, N-H, O-H, F-H
a)
O-H > F-H > N-H > C-H
b)
F-H > N-H > O-H > C-H
c)
C-H > N-H > O-H > F-H
d)
F-H > O-H > N-H > C-H
Answer:
O-H F-H N-Hy
Explanation:
C-H N-H O-H F-H
Which question would most likely be studied by a biologist?
A.
How can a drug that treats cancer be synthesized?
B.
How can cancer-causing substances be regulated?
C.
How much ultraviolet radiation passes through the atmosphere?
D.
What causes cancer cells to grow uncontrollably?
Answer:
The correct answer would be - D. What causes cancer cells to grow uncontrollably?
Explanation:
A Biologist is a person that studies living organisms and the study of living organisms and their process called biology. Biology is a very vast field that involves many branches such as zoology, botany, biochemistry, immunology, biophysics, anatomy, ecology and many more.
So, given all are can be an example of the study biology wanted to do, however, the question most likely studied by a biologist would be What causes cancer cells to grow uncontrollably as it deals with an organism and their biological process.
Which sequence of steps describes the life cycle of a lake?
A. Runoff fills a depression - sediments build up - water becomes
increasingly shallow
B. Runoff fills a depression - sediments are eroded - water becomes deeper
C. Runoff fills a depression - sediments build up
- water rises continuously
D. Runoff fills a depression - sediments are eroded - water spreads over a wider area
Answer:
The actual sequence of steps which describe the life cycle of a lake is given below:
C. Runoff fills a depression - sediments build up
- water rises continuously
Explanation:
This is because, the water which builds up as a result of the runoff water accumulating on the depression helps towards building up. When it must have accumulated greatly, it ends up forming a lake.
Please help I’ll give brainliest
Answer:
N2, O2 and Br2
Explanation:
N2, O2 and Br2 are formed of two atoms, so they are diatomic
This is a list of the seven diatomic elements. The seven diatomic elements are:
Hydrogen (H2)
Nitrogen (N2)
Oxygen (O2)
Fluorine (F2)
Chlorine (Cl2)
Iodine (I2)
Bromine (Br2)
You will not measure the enthalpy of the reaction of ______ in the coffee cup calorimeter because this reaction involves gases. Instead, you will use a well-known published value.
HCI and MgO
HCI and Mg
H2 and O2
Answer:
H2 and O2
Explanation:
A coffee cup calorimeter is basically a type of calorimeter that operates at constant pressure. The heat measured in the calorimeter is equal to the change in enthalpy of the reaction.
This type of calorimeter is apt for reactions involving solutions where there is little or no change in volume.
It is not generally applicable to gas phase reactions such as the reaction between H2 and O2.
Answer:
You will not measure the enthalpy of the reaction of
✔ H2 and O2
in the coffee cup calorimeter because this reaction involves gases. Instead, you will use a well-known published value.
C. H2 and O2
Is Correct
show using dots to illustrate high population density and low population density in the boxes provided in answer to guide questions
Answer:
Just add a plenty of dots in the first one and very few dots in the second one
An area with high population density will have many dots while areas will low population density will have few dots when using dots to illustrate population density.
What is population density?Population density is the ratio of the total number of organisms found in a given area to the total of the area of that place or habitat.
Population density = total number of organisms/total areaAn area with high population density indicates that more organised ate found per unit area than an area with low population density.
Therefore, using dots to illustrate population density, an area with high population density will have plenty dots while areas will low population density will have few dots scattered over.
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Briefly explain why adding insulation to an attic helps reduce heating costs.
Answer:
Insulation reduces the exchange of heat through a surface such as a wall, attic, duct or roof. In a well-insulated home, less warm air escapes from the house during the winter, and less cool air escapes during the summer, reducing the amount of energy needed for heating and cooling
Elias read a book about California earthquakes. He then wrote a three-
paragraph report about the book. Which of the following active reading
strategies did Elias use?
A. Making mental images
B. Drawing inferences
C. Summarizing
D. Making predictions
an engineer chooses to use bamboo as a building material because it grows quickly and needs little space to grow. This is an example of?
Answer:
A) This is an example of Green Design
Explanation:
Describe the four states of matter.
