Answers
Answer:
- 65 kJ
Explanation:
Hess's Law of Constant Heat Summation (or just Hess's Law) states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes
A+2B + B + 2C ===> C +D + 2C+ D
-20kJ -45 kJ ===> 3C + 2D
-65 kJ
Related Questions
The volume of a gas collected when the temperature is 11. 0°c and the pressure is 710 mm hg measures 14. 8 ml. What is the calculated volume of the gas at 20. 0°c and 740 mm hg?.
Answers
Answer:
Original: P₁ = 710 mmHg, V₁ = 14.8 mL, T₁ = (273.2 + 11.0) K = 284.2 K
New: P₂ = 370 mmHg, V₂ = ? mL, T₂ = (273.2 + 20.0) K = 293.2 K
Combined gas law: P₁V₁/T₁ = P₂V₂/T₂
Then, V₂ = V₁ × (P₁/P₂) × (T₂/T₁)
Calculated new volume, V₂ = (14.8 mL) × (710/370) × (293.2/284.2) = 29.3 mL
Answer ASAP! Will award brainleist if correct!!
Answers
Let's see
M1V1=M2V21x=15(2)1x=30x=30mlOption D
How many different consitutional isomers are there for a compound having the molecular formula C3H6O
Answers
Answer:
that make 11 isomers....
What is science? Write a definition for the word
Answers
Answer:
make me brainliest pls :)
Explanation:
Science is both a body of knowledge and a process. In school, science may sometimes seem like a collection of isolated and static facts listed in a textbook, but that's only a small part of the story. Just as importantly, science is also a process of discovery that allows us to link isolated facts into coherent and comprehensive understandings of the natural world.
Science is exciting. Science is a way of discovering what's in the universe and how those things work today, how they worked in the past, and how they are likely to work in the future. Scientists are motivated by the thrill of seeing or figuring out something that no one has before.
Science is useful. The knowledge generated by science is powerful and reliable. It can be used to develop new technologies, treat diseases, and deal with many other sorts of problems.
Science is ongoing. Science is continually refining and expanding our knowledge of the universe, and as it does, it leads to new questions for future investigation. Science will never be "finished."
Science is a global human endeavor. People all over the world participate in the process of science. And you can too!
When liquid bromine is cooled to form a solid, which of the following types of solid would it form?.
Answers
Answer:
If liquid bromine is cooled to form a solid, which type of solid does it form? Brass is made by melting copper and zinc and physically mixing them. As this alloy is cooled, it forms a solid where the copper and zinc are not chemically bonded together.
Explanation:
Describe how you would make 6.0 L of a 0.100 M KCl solution from a 4.0 M stock KCl solution.
Answers
Answer:
0.15 l of 4.0 m stock KCl solution should betaken
Explanation:
N1V1=N2V2
6*0.1=V2*4
V2=0.15L
what are the ways to manage wastes.
Answers
Explanation:
1. Measure your waste
It is easier to manage and track your improvement on something that is measured. Start by recording the types and quantities of waste materials generated within your business.
This could just be a quick visual assessment and estimation of amount and types of waste per week. As you change how you manage your waste, you can compare and see what difference your changes make to the amount of waste disposed to landfill.
2. Reduce
To reduce the amount of waste going to landfill, consider:
can waste be avoided or reduced by the way you procure goods and services or by changing your business operations?
does another local business have a use for the waste materials produced by your business?
what materials can be targeted for recycling?
3. Recycle
Find out what options are available locally for business recycling.
4. Collection services
It is a good idea to find out how levy fees will be managed by your waste service provider, and find out more about your waste collection services—how it impacts your ability to recycle and what options are available to you.
5. Separating waste
It’s important to ensure that waste is correctly separated for recycling. Putting the wrong waste in contaminates the recycling. Check out the free-to-download recycling signage to help businesses communicate correct recycling and waste separation behaviours.
The _______ is the part of the neuron that carries information away from the cell body.
cell body
axon
dendrite
nucleus
Answers
it is where electrical impulses from the neuron travel away to be received by other neurons!
Answer:
b
Explanation:
What are some downsides to fossil fuels? (Select all that apply.) pls help im timed
They are expensive to extract compared to other forms of energy.
They release large amounts of carbon dioxide when burned.
They do not replenish themselves.
They are in a limited supply.
Answers
Answer:
B, C and D
Explanation:
Fossil fuels include coal, petroleum, natural gas, oil shales, bitumens, tar sands, and heavy oils. When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the air.
Although fossil fuels are continually formed by natural processes, they are classified as non-renewable resources because they take millions of years to form.
fossil fuels, are called nonrenewable, which means they have a limited supply and are not continuously being made or they are made very slowly
A chemist wants to make 750mL of a 6M NaOH solution. What mass (in grams) of NaOH will they need?
Answers
Answer:
180 g NaOH
Explanation:
Step #1 : Use the molarity equation to find moles. The volume is needed in liters, so convert the milliliters to liters.
Molarity (M) = moles (mol) / liters (L) ---->
Molarity (M) x liters (L) = moles (mol)
750 mL NaOH 1 L
x ---------------- = 0.75 L NaOH
1,000 mL
(6 M NaOH) x (0.75 L NaOH) = ? mol
= 4.5 mol NaOH
Step #2 : Find the mass using the moles and the molar mass of the solution. The molar mass can be calculated using the values of the elements on the periodic table.
Molar Mass (g/mol) = grams (g) / moles (mol) --->
Molar Mass (g/mol) x moles (mol) = grams (g)
? g/mol = (22.99 g/mol Na) + (15.999 g/mol O) + (1.008 g/mol H)
? g/mol = 39.997 g/mol NaOH
(39.997 g/mol NaOH) x (4.5 mol NaOH) = ? g
= 179.99 g NaOH
= 180 g NaOH (2 sig figs)
= 200 g NaOH (1 sig fig)
The activity of a radioisotope is 3000 counts per minute at one time and 2736 counts per minute 48 hours later. What is the half-life, in hours, of the radioisotope
Answers
The activity of a radioisotope is 3000 counts per minute at one time and 2736 counts per minute 48 hours later, then the half life time is 365 hours.
How do we calculate the half life time?Half life time for the first order reaction will be calculated by uisng the below equation as:
k = 0.693/t, where
t = half life time
k is the rate constant and its value will be calculatedy using the below equation as:
ln(No/N) = kT, where
No = initial concentration of radioisotope = 3000
N = remaining contentration of radioisotope = 2736
T = time require for above change = 48 hours
On putting these values on above equation, we get
k = ln(3000/2736) / 48 = 0.0019
Now putting this value in the first equation, we get
t = 0.693/0.0019 = 364.7 = 365 hours
Hence half life time is 365 hours.
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Which of these solutions is the most basic?
Your answer:
[OH-] = 4.3 x 10-9 M
[OH-] = 2.8 x 10-11 M
[OH-] = 6.7 x 10-10 M
[OH-] = 1.0 x 10-5 M
Answers
Which of these solutions is the most basic?
[OH-] = 4.3 x 10-9 M
[OH-] = 2.8 x 10-11 M
[OH-] = 6.7 x 10-10 M
[OH-] = 1.0 x 10-5 M
Answer↷[OH-] = 1.0 x 10-5 M ✓ Solution↷[OH-] = 4.3 x 10-9 M
[OH-] = 4.3 x 10^-9 MpOH = - log [OH^1-]pOH = - log [4.3 x 10^-9]pOH = 8.36pH = 14- 8.36pH = 5.64_______________________________________
[OH-] = 2.8 x 10-11 M
[OH-] = 2.8 x 10^-11 MpOH = - log [OH^1-]pOH = - log [2.8 x 10^-11 ]pOH = 10.55pH = 14-10.55pH = 3.45_______________________________________
[OH-] = 6.7 x 10-10 M
[OH-] = 6.7 x 10^-10 MpOH = - log [OH^1-]pOH = - log [6.7 x 10^-10]pOH = 9.17pH = 14-9.17pH = 4.83_______________________________________
[OH-] = 1.0 x 10-5 M
[OH-] = 1.0 x 10-5 M pOH = - log [OH^1-]pOH = - log [1.0 x 10^-5 ]pOH = 5pH = 14-5pH = 9_______________________________________
we know that , the solution with pH > 7 is termed as basic and more the pH ,more the basicity, hence ,the solution with the highest pH would be the strongest base out of these all which is
[OH-] = 1.0 x 10-5 M with pH = 9
_______________________________________
Note the rule
pOH=-log[OH-]And we can find the answer through logarithm rules basic
loga^b=blogaSo
-log10^-n=nHigher the n higher the pOH
But
pH=14-pOHLesses pOH=Higher pH i.e basic HighAs we can see
Option D has least n (5)
Hence D is more basic
What are the spectator ions in the
following reaction?
NiS (s) + 2HCl(aq)
NiCl₂(aq) + H₂S(g)
B
S²-
CIT
Answers
Answer:
S
Explanation:
~cosmic snowball ~orbits our Sun ~frozen gases, rock and dust ~may have brought water to Earth ~dust and gases form a tail that stretches away from the Sun The prompt above is describing what celestial body?
Answers
Answer:
A comet
Explanation:
Comets travel so fats through the solar system that they melt which give them their glowy tail
Plan an investigation to explore the evidence that an electric current produces a magnetic field, and that a changing magnetic field produces an electric current.
Answers
Answer:
Give evidence for the existence of a magnetic field near a current carrying wire. If you hold a compass near a wire through which current is flowing, the needle on the compass will be deflected.
Sulfur burns in the air to form 33.6L of sulfur dioxide. (S = 32, O =16, 64g of sulfur dioxide has 22.4L, 32g of oxygen has 22.4L)
find mass of reacted oxygen
find mass of required oxygen
Answers
The mass of oxygen reacted/required in this reaction is obtained as 48g.
What is stoichiometry?The term stoichiometry has to do with mass- volume or mass - mole relationship which ultimately depends on the balanced reaction equation.
Now, we have the reaction; S + O2 ------>SO2
If 1 mole of sulfur dioxide contains 22.4 L
x moles of sulfur dioxide contains 33.6L
x = 1.5 moles of sulfur dioxide.
Since the reaction is 1:1, the number if moles of oxygen required/reacted is 1.5 moles.
Mass of oxygen required/reacted = 1.5 moles * 32 g/mol = 48g
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What is the concentration, in molarity, of a solution that contains 19g of NaOH dissolved into water to make 500 mL of solution?
Answers
Answer:
The molar concentration of NaOH in the final diluted solution is 0.056 M
Explanation:
How many hydrogen molecules are in 1.2 moles of hydrogen?
7.2 x 10^23
0.19 x 10^23
1.9 x 10^24
4.8 x 10^23
Answers
Answer:
7.2 x 10^23
Explanation:
Currently in Chemistry class
A sample of oxygen occupies a volume of 250. liters at 375 K. Predict the volume of the sample, when the temperature drops to 280. K with constant pressure.
A. 164 L
B. 187 L
C. 223 L
D. 352 L
Answers
Answer:
187 L
Explanation:
its the correct answer on smartsparrow.
What is the empirical formula of a compound that is 41.4% Strontium, 13.24%
Nitrogen, and 45.3696 Oxygen
Answers
Empirical Formula StepsN2O6Sr Strontium Nitrate
Explanation:
Proponents of breast feeding often cite the passing of antibodies to the infant as a benefit. This type of immunity would be considered
artificial active immunity.
natural active immunity.
natural passive immunity.
vaccination.
artificial passive immunity.
Answers
Answer:
Natural passive immunity
Explanation:
Breatsfeeding is natural....
antibodies passes from the parent to the infant...
The infant gets nutrition in which later antibodies will be formed by the nutrients..
Will give brainliest
What is the second quantum number of a 1s2 electron in phosphorus, 1s22s22p63s23p3?
Answers
freshwater is distributed in both time and space
Answers
Unevenly
Explanation:
Fresh water is distributed unevenly in both time and space.
What aspect of water makes it favorable to use in steam distillation?.
Answers
Answer:
The low molecular weight of water makes water a favorable liquid for steaming
The overall equation for the electrolysis of aluminium oxide is:
2Al2O3
4Al + 302
Calculate the mass of oxygen produced when 2000 kg of aluminium oxide is
completely electrolysed.
Relative atomic masses (A):
O = 16
Al = 27
Answers
941539.2 g of mass of oxygen is produced when 2000 kg of aluminium oxide is completely electrolysed.
What is electrolysis?Electrolysis is the process by which electric current is passed through a substance to effect a chemical change.
The mass of aluminium oxide Al₂O₃ = 2000 kg = 2000 000 g
Molar mass of Al₂O₃ = 101.96 g/mol
no of moles = [tex]\frac{mass }{ molar \;mass}[/tex]
no of moles of Al₂O₃ = [tex]\frac{2000 000 g}{101.96 g/mol}[/tex]
no of moles of Al₂O₃ = 19615.4 mol
From the reaction:
4Al + 3O₂ ⇒ Al₂O₃
To determine the moles of O₂ in Al₂O₃:
Then;
19615.4 mol X [tex]\frac{3}{2}[/tex] mol of O₂ = 29423.1
The mass of oxygen now = 29423.1 × 32 g
= 941539.2 g
Hence, 941539.2 g of mass of oxygen is produced when 2000 kg of aluminium oxide is completely electrolysed.
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A beaker filled with freshwater has a p h balance of 6.65. geraldo wants to model the effect of acids on the ph of water for a group of students. which pollutant should geraldo add to the water? what will the ph reading be after geraldo adds the pollutant?
Answers
Geraldo can add a pollutant with slightly basic nature so he will have a solution of neutral pH of 7.
What is pH?The pH of a solution is the negative logarithm to base ten of the hydrogen ions concentration of the solution.
The pH of 6.5 means that the solution is acidic.
By adding a pollutant which is slightly basic in nature, Geraldo will have a solution of neutral pH which is a pH of 7.
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Answer:
1.pesticide
2.less than 6.65
Explanation:
Explain the relationship by between society and the Technologies of using earths resources
Answers
Answer:
We used coal for electricity, water for steam engines when we used them, natural fossil fuels for gasoline and oil and we use earths oxygen/nitrogen gases to breathe
Explanation:
Hope this helps:)....if not then sorry for wasting your time and may God bless you:)
A sample of radon gas has a volume of 1.53 L, a pressure of 1.15 atm, and a temperature of 305 K. What is the new pressure if the new volume is 1.78 and the new temperature is 325 K
Answers
Answer: 0.813 L
Explanation:
Ideal gas law is valid only for ideal gas not for vanderwaal gas. Combined Boyle's and Charles' gas law is used here. Therefore the new pressure of helium gas is 5.63 atm.
What is ideal gas equation?Ideal gas equation is the mathematical expression that relates pressure volume and temperature.
Mathematically the relation between Pressure, volume and temperature can be given as
PV=nRT
where,
P = pressure of radon gas
V= volume of radon gas
n =number of moles of radon gas
T =temperature of radon gas
R = Gas constant = 0.0821 L.atm/K.mol
Combining Boyle's and Charles' gas law
P₁V₁/T₁ = P₂V₂/T₂
{ (1.15 atm) (1.53 L)} ÷305 K ={ (P2) ( 1.78)} ÷325 K
P2 = 7.55÷1.34 = 5.63 atm
Therefore the new pressure of radon gas is 5.63 atm when the temperature is changed to 325K and volume is decreased to 1.78liter.
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For a given voltaic cell, you double the concentrations of all soluble components to 2.0 M instead of the standard 1.0 M. All other conditions are standard. What happens to the cell emf
Answers
If the concentration of the solutions are doubled then the cell EMF is also doubled.
Nernst equationAccording to the Nernst equation, the concentration of the species determines the cell EMF as we can see form the formula;
Ecell = E°cell - 0.0592/nlogQ.
Hence, if the concentration of the solutions are doubled then the cell EMF is also doubled.
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Is a pearl a mineral? Explain your answer thoroughly. Read the description in the reference image to help you determine the answer.
HELP!! IM SO BAD AT SCIENCE!! PLEASE ANSWER AS SOON AS POSSIBLE
Answers
Answer:
A pearl is not a mineral
Explanation:
Even though a pearl is made up of a few little overlapping platelets of certain minerals such as aragonite, which is the stable form of calcium carbonate which is a necessary component for sealife. Why is a pearl not a mineral though? Yes a pearl is made up of mineral compounds, but its organic origins take away its ability to be included as a mineral. Pearls do not have distinctive crystal structures and are formed by living organisms.