Answer:
Q = 44.5 kJ
Explanation:
Given that,
Mass of water, m = 112 g
Water at 50.0°C cools to form ice at −45.0°C
We need to find the total amount of heat released. The formula for heat released is given by :
[tex]Q=mc\Delta T[/tex]
c is the specific heat of water, c = 4.184 J/g°C
So,
[tex]Q=112\times 4.184 \times (-45-50)\\\\Q=-44517.76\ J[/tex]
or
Q = -44.5 kJ
So, 44.5 kJ of heat is released.
If 1.546 g of copper was used by a student at the start of the lab, and 0.732 g of copper were obtained at
the end of the series of reactions, what was the percent recovery? Briefly explain how you found your
answer.
Answer: Percent recovery is 47.34 %
Explanation:
Percent yield is defined as the ratio of experimental yiled to theoretical yield in terms of percentage.
[tex]{\text{ percent yield}}=\frac{\text{amount recovered}}{\text{total amount}}\times 100[/tex]
Putting in the values we get:
[tex]{\text{ percent yield}}=\frac{0.732}{1.546}\times 100=47.34\%[/tex]
Therefore, the percent recovery is 47.34 %
What does not affect the strength of an electromagnet?
Answer:
Unlike a permanent magnet, an electromagnet can be turned on and off using electrical current. Many variables affect the strength of this electromagnet, and there are some variables that do not affect the strength. ... Making the nail longer will not make the magnet stronger, unless you also add more turns to the coil.
electromagnet can be turned on and off using electrical current. Many variables affect the strength of this electromagnet, and there are some variables that do not affect the strength
A purified protein is in a HEPES buffer at pH 7.0 with 600 mM NaCl. A 1 mL sample of the protein solution is dialyzed against 1.0 L of the same HEPES buffer with 0 mM NaCl. Once the dialysis has come to equilibrium, what is the concentration (in mM) of NaCl in the protein sample
Answer:
Explanation:
Using the dilution formula to determine the final concentration of NaCl in the protein sample.
[tex]M_1V_1 = M_2V_2[/tex]
[tex]600 \ mM \times 1 \ mL= M_2 \times ( 1000\ mL + 1 \ mL)[/tex]
[tex]M_2= \dfrac{600 \ mM \times 1 \ mL}{ ( 1001\ mL)}[/tex]
[tex]M_2= 0.599 \ mM[/tex]
However, when dialysis attains equilibrium, it implies that the sample was dialyzed twice, SO:
[tex]M_2 = \dfrac{600 \ mM\times 1 \ mL}{201 \ mL} = 2.97 \ mM[/tex]
Now, take the concentration as 2.97 mM
Then:
[tex]M_f = \dfrac{2.985 mM \times 1 mL}{201 \ mL}[/tex]
[tex]M_f = 0.01485 \ mM[/tex]
[NaCl] = 0.01485 mM
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
Today, ammonia is synthesized through a series of reactions (called the Haber-Bosch process) that take place between methane, air (which is four parts N2, one part O2), and potassium carbonate:
7 CH4(g) + 8 N2(g) +2 O2(g) + 17 H2O(g) + 7 K2CO3(s) ?? 16 NH3(g) + 14 KHCO3(s)
What is the equilibrium expression for the Harber-Bosch process?
Answer:
K = [NH₃]¹⁶ [KHCO₃]¹⁴ / [CH₄]⁷ [N₂]⁸ [O₂]² [H₂O]¹⁷ [K₂CO₃]⁷
Explanation:
The equation for the reaction is given below:
7CH₄(g) + 8N₂(g) +2O₂(g) + 17H₂O(g) + 7K₂CO₃(s) —> 16NH₃(g) + 14KHCO₃(s)
Equilibrium constant (K) =..?
Equilibrium constant, K for a reaction is simply defined as the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.
Thus, the equilibrium expression for the Harber-Bosch process for the synthesis of ammonia can be written as shown below:
K = [NH₃]¹⁶ [KHCO₃]¹⁴ / [CH₄]⁷ [N₂]⁸ [O₂]² [H₂O]¹⁷ [K₂CO₃]⁷
Riboflavin is one of the B vitamins It is also known as B6 and is made up of carbon, hydrogen, nitrogen and oxygen atoms. When 10.0 g of vitamin B6 is burned in oxygen, 19.88 g of CO2 and 4.79 g of H2O are obtained. Another experiment shows that vitamin B6 is made up of 14.89% of N. What is the simplest formula for vitamin B6
Answer:
C₁₇H₂₀N₄O₆
Explanation:
First, we need to determine the percentage of the atoms in the molecule. Then, assuming a basis of 100 we must convert the mass of each atom to moles. Simplest formula is the simplest ratio of atoms presents in the molecule:
%C:
19.88g CO2 * (12.01g/mol C / 44.01g/mol CO2) = 5.425g C
5.425g C / 10.0g * 100 = 54.25% C
%H:
4.79g H2O * (2*1.01g/mol / 18.015g/mol) = 0.537g H
0.537g H / 10.0g * 100 = 5.37%
%N:
14.89%
%O:
100 - 14.89% - 54.25% - 5.37% = 25.49%
Moles of each atom in a basis of 100g:
C: 54.25g * (1mol / 12.01g) = 4.517moles
H: 5.37g * (1mol / 1.01g) = 5.317 moles
N: 14.89g * (1mol / 14.01g) = 1.063 moles
O: 25.49g * (1mol / 16g) = 1.593 moles
Dividing each amount of moles in the lower number of moles (moles N):
C = 4.517mol / 1.063mol = 4.25
H = 5.317mol / 1.063mol = 5
N = 1.063mol / 1.063mol = 1
O = 1.593mol / 1.063mol = 1.5
This ratio multiplied 4 times to obtain whole-numbers:
C = 4.25*4 = 17
H = 5*4 = 20
N = 1*4 = 4
O = 1.5*4 = 6
The simplest formula for vitamin B6 is:
C₁₇H₂₀N₄O₆helppp nowwww plsssss!!
Answer:
The sun will appear to rise and set more slowly
have a nice day! (^o^)
What is the charge is the ion when lithium reacts with chlorine
Will measuring the melting point of your product tell you that your product is relatively pure?
Answer and Explanation:
Yes. The determination of melting point is used to analyze if a solid compound is pure or impure. The melting point of a pure solid product does not vary in a narrow range, whereas if impurities are present the solid melts in a broad range of temperatures. For this reason, this technique is generally used to determine the identity and purity of the products obtained in chemical reactions.
In a laboratory setting, concentrations for solutions are measured in molarity, which is the number of moles per liter (mol/L). Concentrations are often converted to more common units on the labels of household products. For a particular brand of bleach, the concentration of sodium hypochlorite (NaClO) is reported on the bottle as 7.25% by mass. The following information can thus be used to calculate the molarity of NaClO in the bleach:
• 1L of bleach has a mass of 1,100 grams.
• 7.25% of the mass of bleach is NaClO.
• 1 mol of NaClO has a mass of 74.44 grams.
What is the molarity (mol/L) of NaClO in the bleach?
A.0.097
B.0.93
C.1.07
D.79.75
Answer:
its C
Explanation:
1/74.44 * 79.75 = 1.07
The molarity (mol/L) of NaClO in the bleach, given the data is 1.07 mol/L (Option C)
What is molarity?Molarity is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:
Molarity = mole / Volume
How to determine the mass of NaClO in the bleachMass of bleach = 1100 gPercentage of NaClO = 7.25%Mass of NaClO = ?Mass of solute = percent × mass of solution
Mass of NaClO = 7.25% × 1100
Mass of NaClO = 0.0725 × 1100
Mass of NaClO = 79.75 g
How to determine the mole of NaClO Mass of NaClO = 79.75 gMolar mass of NaClO = 74.44 g/moleMole of NaClO =?Mole = mass / molar mass
Mole of NaClO = 79.75 / 74.44
Mole of NaClO = 1.07 mole
How to determine the molarity Mole of NaClO = 1.07 moleVolume = 1 L Molarity of NaClO =?Molarity = mole / Volume
Molarity of NaClO = 1.07 / 1
Molarity of NaClO = 1.07 mol/L
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When a substance undergoes a chemical change, its identity does not change.
O True
O False
Answer:
False
Explanation:
Chemists make a distinction between two different types of changes that they study—physical changes and chemical changes. Physical changes are changes that do not alter the identity of a substance. Chemical changes are frequently harder to reverse than physical changes.
How can you model the cycling of matter in the Earth system?
Answer:
The cycling of matter is important to many Earth processes and to the survival of organisms the existing matter must cycle continuously for this planet to support life Water, carbon, nitrogen, phosphorus, and even rocks move through cycles If these materials did not cycle, Earth could not support life.
Explanation:
Earth activities depend on matter cycling, and for organisms to survive, this planet's surface must cycle with the flow of matter.
What is Earth system?Rocks, as well as water, carbon, nitrogen, and phosphorus, go through cycles. The planet Earth could not support life if these materials did not cycle.
Subsystems exist within the Earth system. These subsystems include the exosphere, atmosphere, hydrosphere, lithosphere and geosphere, also referred to as the lithosphere, and the living environment (biosphere).
These systems are powered by energy that comes from both the Sun and the interior of the Earth. Through processes known as biogeochemical cycles, nutrients and elements also move through these systems along with energy.
Therefore, Earth activities depend on matter cycling, and for organisms to survive, this planet's surface must cycle with the flow of matter.
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Enter your answer in the provided box. Muriatic acid, an industrial grade of concentrated HCl, is used to clean masonry and cement. Its concentration is 11.7 M. For routine use, a diluted solution of 3.50 M is prepared. How many milliliters of 3.50 M muriatic acid solution contain 32.8 g of HCl
Answer:
257 mL
Explanation:
Step 1: Given data
Concentration of the muriatic acid solution used (C): 3.50 M (3.50 mol/L)Mass of HCl (m): 32.8 gStep 2: Calculate the moles (n) corresponding to 32.8 g of HCl
The molar mass of HCl is 36.46 g/mol.
32.8 g × 1 mol/36.46 g = 0.900 mol
Step 3: Calculate the volume (V) of solution required
We will use the following expression.
C = n/V
V = n/C
V = 0.900 mol/(3.50 mol/L)
V = 0.257 L = 257 mL
ASAP I WILL GIVE BRAINLIEST The diagram shows a lever. What is the mechanical advantage of the lever? O 2 03 3 m 6 m mi 0 9
Answer:
A) 2
Explanation:
Answer:
2, i got it right thanks to the other user :) <3
Explanation:
Which statement gives a disadvantage of multicellular organisms?
A. They need small amounts of energy
B. They reproduce slower than unicellular organisms
C. They can perform more functions
D. Cells are able to provide support
Answer: B. They reproduce slower than unicellular organisms
Explanation:
In unicellular organisms there is a single cell which performs all the functions like digestion, respiration, and reproduction. The cell reproduce by cell division. The single parent cell divides into two identical daughter cells. But multicellular organisms exhibit multiple cells and their reproduction is complex. They reproduce by sexual mode of reproduction in which separate sex cells are produced when they fuse form zygote which is the precursor of new organism. This process is slower than that of the cell division and production of progeny by the unicellular organisms. Thus reproduction is slower in multicellular organism this is the disadvantage in multicellular organisms.
Answer:
B. they reproduce slower than unicellular organisms
Explanation:
is C5H10 ionic or covalent?
The 10x SDS gel electrophoresis buffer contains 250mM Tris HCl, 1.92M Glycine, and 1% (w/v) SDS. Buffers are always used at 1x concentration in the lab (unless specified otherwise in the protocol), so you will have to dilute the 10x buffer to 1x before use. What is the concentration of Tris and SDS in the 1x buffer
Answer:
25 mM Tris HCl and 0.1% w/v SDS
Explanation:
A 10X solution is ten times more concentrated than a 1X solution. The stock solution is generally more concentrated (10X) and for its use, a dilution is required. Thus, to prepare a buffer 1X from a 10X buffer, you have to perform a dilution in a factor of 10 (1 volume of 10X solution is taken and mixed with 9 volumes of water). In consequence, all the concentrations of the components are diluted 10 times. To calculate the final concentration of each component in the 1X solution, we simply divide the concentration into 10:
(250 mM Tris HCl)/10 = 25 mM Tris HCl
(1.92 M glycine)/10 = 0.192 M glycine
(1% w/v SDS)/10 = 0.1% w/v SDS
Therefore the final concentrations of Tris and SDS are 25 mM and 0.1% w/v, respectively.
Please help me thanks so much?!?!?
Answer:
color
Explanation:
Answer:
D
Explanation:
The five conditions of chemical change: color chage, formation of a precipitate, formation of a gas, odor change, temperature change and the others are just physical changes that would happen if you change containers, or let it evaporate.
Which equation shows how to solve for enthalpy of solution based on the information in tables?
Answer: B. triH sol Mgl2= -triHlat+ triHhydr Mg^2+ 2triHhydr^l-
Explanation:
Just did it and it was right
When preparing for work in the fume hood, be sure to gather all necessary tools, glassware, and chemicals _________ to minimize the number of times the hood sash is raised and lowered. Work as much as possible in the _________ of the work surface to keep the area tidy and promote air flow. If you need to step away from the experiment to obtain another item, _________ the sash during this time.
Answer:
In advance
middle
lower
Explanation:
These are the safety precautions needed when carrying out duties in the fume hood.
When planning and preparing to work in a fume hood (a locally designed area to reduce exposure to hazardous fumes). It is advisable to make all equipment readily available at your disposal in advance to reduce and minimize the raising and lowering of the hood sash at intervals.
It is also pertinent to understand that working in the middle of the work surface helps to promote the movement of air and keeps the area neat and tidy.
However, if any case where there is a need to get a new tool or equipment during the process of working in a fume hood, it is advisable to lower the sash at that point in time.
a dragster in a race accelerated from rest to 60 m/s by the time it reached the finish line. the dragster moved the distance from start to finish in 8.3 seconds. what is the dragsters acceleration?
i’ll mark brainliest!!
Answer:
7.23m/s²
Explanation:
Given parameters:
Initial velocity = 0m/s
Final velocity = 60m/s
Time taken = 8.3s
Unknown:
Acceleration of the dragsters = ?
Solution:
Acceleration is defined as the rate of change of velocity with time taken.
So;
Acceleration = [tex]\frac{Final velocity - Initial velocity }{time}[/tex]
Acceleration = [tex]\frac{60 - 0}{8.3 }[/tex] = 7.23m/s²
What role do wolves play in the tundra?
Answer:
predator
Explanation:
Wolves, arctic foxes, and snowy owls are predators in the tundra.
Describe the relationship between kinetic energy and the states of matter?
PLS HELP I DONT SCIENCE HELP ASAP HELP
Answer:
The kinetic molecular theory of matter states that: Matter is made up of particles that are constantly moving. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.
Explanation:
Find the mass in grams of 1.38 moles of Sr
Answer:
116.78 grams.
Explanation:
1 mol of Strontium (Sr) = 87.62 grams
1.38 mol of Strontium = x
Cross Multiply
1 * x = 1.38 * 87.62
x = 116.78 grams
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.
3.
What do we call materials
that let heat pass through
them easily?
Thermal conductors
Thermal insulators
Transparent
4.
Which of these is a good
thermal conductor?
Plastic
Wood
Steel
5.
Which of these is a good
thermal insulator?
Steel
Iron
Polystyrene
6.
To save on heating bills, do
you think the roof of a
building should be lined with...
a thermal conductor
a thermal insulator
nothing
7.
How does heat travel?
From cold things to hotter things
From hot things to colder things
Between things of the same temperature
Answer:
thermal conductors
steel
polystyrene
thermal insulator
between things of the same temp?
sorry to ask but if its ok with you, may i get brainly, i need to rank up all i need is two more, if not its fine. thank you and yours truly golden
Plz help ASAP i will give brainlists
2AgNO3 + BaCl2 + 2AgCl + Ba(NO3)2
How many grams of silver chloride are produced from 15.0 g of silver nitrate reacting with an excess of barium chloride?
A)9.44 g Agci
B)16.4 g Agci
C)12.7 g Agci
D)0 20.1 g Agci
An scientist located a nugget of an unknown substance. However, he determined that this nugget has a
mass of 63 g and a volume of 9 cm^3. What is the density of this nugget?
Answer: The density of this nugget is [tex]7\text{ g cm}^{-3}[/tex] .
Explanation:
We are given that,
Mass of nugget = 63 g
Volume = [tex]9\ cm^3[/tex]
The computation of density of a substance is given by :-
[tex]\text{Density}=\dfrac{\text{Mass}}{\text{Volume}}\\\\\Rightarrow\ \text{Density}=\dfrac{63}{9}\text{ g cm}^{-3}[/tex]
[tex]\Rightarrow\ \text{Density =}7\text{ g cm}^{-3}[/tex]
Therefore, the density of this nugget is [tex]7\text{ g cm}^{-3}[/tex] .
Experiments were done on a certain pure substance X to determine some of its properties. There's a description of each experiment in the table below. In each case, decide whether the property measured was a chemical or physical property of X, if you can. If you don't have enough information to decide, choose can't decide in the third column.
Property P: A small sample of X is dissolved in water. Drops of another solution, containing dissolved sodium hydroxide, are slowly added, and a pH indicator is used to determine when the sodium hydroxide has completely reacted with X. From the amount of sodium hydroxide needed, the value of P may be calculated.
Property D: A sample of X is carefully weighed and put inside a vented flask. Water is added to the flask until it just covers the sample, and the volume of sample and water is recorded. Then the sample is removed and the volume of water alone recorded. From the mass of the sample and the difference in volumes, the value of R may be calculated.
Property V: Sample of X is melted and put into a reservoir from which a very thin tube leads down. The rate at which X flows out of the tube is measured, and from this rate the value of V may be calculated.
Answer:
The property P measured, was a chemical property of X; its acidity
The property D measured, was a physical property of X; its density
The property V measured, was a physical property of X; it's viscosity probably.
Explanation:
1. The property V that was measured is the acidity of X. The acidity of X is a measure of the concentration of hydrogen ions present in it. When drops of another solution, containing dissolved sodium hydroxide, are slowly added, and a pH indicator is used to determine when the sodium hydroxide has completely reacted with X, the procedure determines the concentration of X that would neutralize the base, sodium hydroxide.
2. The property of X determined in the step is the density of X, a physical property. First the volume of X was determined by the displacement method. Then the density of X is calculated from its mass and volume.
3. Since during the determination of the property V, there was no alteration done to the chemical constitution of X, the property thus determined is a physical property. Melting of the sample is a physical change and likewise its flow rate through a very thin tube.
The octet rule states that atoms in molecules share electrons in such a way that each atom has a full valence shell. Determine whether each structure has the correct number of electrons and obeys the octet rule. Classify structures that have the correct number of electrons and obey the octet rule as valid, and those that do not as invalid. valid structure invalid structure
Answer:
Their must be a picture with this question so we can answer it
Explanation:
According to octet rule the bonded valence shells are completely filled. All the compounds except the first one, CH₃CH₃O is invalid since H does not obey the rule and invalid.
What is octet rule?Octet rule says that an atoms become stable when it completes its valence shell to 8 electrons or 2 electrons for K-shell. Thus bonded shells have to completely filled to be stable.
Each atom shares its electrons based on its valency. For example carbon have a valency of 4 and it forms for bonds and oxygen and sulfur have two and hydrogen forms only one bonds.
In the first compounds CH₃CH₃O, where one H forms two bonds which is not possible and invalid.
In the second compound CONH, all the atoms satisfies its valency including nitrogen having a valency of three forms three bonds. Similarly in CH₂F₂, one fluorine forms one bond and the structure is valid.
In the case of Br₂ , each bromine shares one electron with the other and complete their octet to eight electrons. In NH₃, SCO and COCl₂ all the atoms satisfies their valency and the structures are valid.
Therefore the only invalid structure is first compound, remaining all are valid.
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Your question is incomplete. But most probably your complete question was as in the uploaded image.