Answer:
39.7%
Explanation:
To obtain the percentage composition of chromium (Cr) in Na₂Cr₂O₇, do the following:
Molar mass of Na₂Cr₂O₇ = (23×2) + (52×2) + (16×7)
= 46 + 104 + 112
= 262 g/mol
Mass of Cr in Na₂Cr₂O₇ = 2 × 52 = 104 g
Percentage composition of Cr = mass of Cr / Molar mass of Na₂Cr₂O₇ × 100
= 104 / 262 × 100
= 39.7%
Thus, the percentage composition of chromium (Cr) in Na₂Cr₂O₇ is 39.7%
What’s this answer help me out
Draw the structures of organic compounds A and B. Indicate stereochemistry where applicable The starting material is ethyne, a carbon carbon triple bond where each carbon is bonded to a hydrogen. Step 1 is N a N H 2 followed by 1 equivalent of C H 3 C H 2 C H 2 B r to form compound A. Compound A reacts with hydrogen and lindlar's catalyst to form compound B. COmpound B reacts with H 2 O and H 3 O Plus to form a 5 carbon chain with a hydroxy substituent on carbon 2.
Answer:
See explanation below
Explanation:
In this case we have the starting reactant which is the ethine, In the first step reacts with NaNH₂, a strong base. This base will substract the hydrogen from one of the carbon of the ethine, and form a carbanion. This will react with the propane bromide, displacing the bromine and forming a 5 carbon chain with the triple bond on the carbon 1 and 2.
In the second step, reacts with the lindlar catalyst to do a reduction, and form a double bond between carbon 1 and 2. In essence, compound A is similar to compound B.
Finally B reacts with water in acid and makes a addition reaction, and form an alcohol.
The whole process can be seen in the picture below.
Hope this helps
What is the mass of 2.2 moles of magnesium chloride? With work shown
A student dissolves 14.8 g of ammonium nitrate (NH4NO2) in 300. g of water in a well-insulated open cup. He then observes the temperature of the water fall from 20.0°C to 15.0°C over the course of 4.3 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction:
NH4NO3(s) → NH4+(aq) + NO3^- (aq)
Required:
a. Is this reaction exothermic, endothermic, or neither?
b. If you said the reaction was exothermic or endothermic, calculate the amount of heat that was released or absorbed by the reaction in this case.
Answer:
a. Endothermic
b. 6586J are absorbed.
Explanation:
a. When the reaction occurs, the temperature is decreasing from 20.0°C to 15.0°C, that means the reaction is absorbing heat and is endothermic.
b. To find the heat absorbed we must use:
Q = -m*ΔT*C
Where Q is change in heat,
m is the mass of solution (300g + 14.8g = 314.8g)
ΔT is change in temperature (15.0°C - 20.0° = -5.0°C)
And C is specific heat of the solution (4.184J/g°C assuming is the same heat than the heat of pure water).
Replacing:
Q = -314.8g*-5.0°C*4.184J/g°C
Q =
6586J are absorbed
A heterogeneous ore mixture contains 35.0 % In2O3 by mass. How many tons of the ore must be mined to provide 325.0 kg of indium metal? (2000 lb = 1 ton, assume exact)
Answer:
1.2375 ton of ore
Explanation:
Mass of indium = 325
Formula = In2O3
Molar mass = 277.64 g/mol
Molar mass of indium = (2*114.8)g
229.6 indium is in 277.64 of In2O3
Mass of In2O3 required = 277.64/229.6 x 325
= 392.94kg
35 % In2O3 in ore
For 35 kg = 100 kg required
For 392.94,
100/35 x 392.94
= 1122.686 kg
1122.68 x 2.2
= 2469.9 pounds
2469.9/200
= 1.235 tons of ore
What kind of questions do scientists ask?
A. Ones that there are no right answers to
B. Ones that only deal with scientific issues
C. Ones that deal with matters of opinion
D. Ones that are answered through observing
ones that are answered through observing :)
Answer: D.
Explanation:
ones that are answered through observing.
The spot on the fault where the pressure first releases is called the
Answer:
This movement releases energy and generates seismic waves that can be recorded by specialized instruments used by scientists. The point on a fault at which the first movement or break occurs during an earthquake is called the earthquake's hypocenter
Explanation:
Danielle is designing a system to help race cars slow safely and rapidly at her local racetrack. The racetrack is a straight, 1,000-meter stretch of asphalt. Half of the track is devoted to races and the other half is designed to let cars decelerate after crossing the finish line.
Danielle has designed a pair of small parachutes that are automatically released out the back of a car once it crosses the finish line. When her system works properly, the race car driver does not need to apply the brakes to bring the car to a stop before running out of track.
When Danielle tests a prototype of her design, it brings a race car to a stop 275 meters behind the finish line. After taking some measurements, she decides that her design causes the driver to experience too much force. To correct this, she could
A.
make the parachutes larger in order to increase the drag forces on the car and bring it to a stop 200 meters after crossing the finish line.
B.
add a third parachute in order to increase the drag forces on the car and bring it to a stop 175 meters after crossing the finish line.
C.
make the parachutes smaller in order to decrease the drag forces on the car and bring it to a stop 400 meters after crossing the finish line.
D.
remove one of the parachutes in order to decrease the drag forces on the car and bring it to a stop 550 meters after crossing the finish line.
Answer:
The answer is C
Explanation:
She should make the parachutes smaller in order to decrease the drag forces on the car and bring it to a stop 400 meters after crossing the finish line.
Many inland areas around Florida contain extinct marine fossils. Which of the following statements best describes how this might have occurred?
Answer:
D
Explanation:
strong winds carried marine organisms inland where they were buried and fossilized under layer of sediment
Answer:
Strong winds carried marine organisms inland where they were buried and fossilized under layers of sediment.
Explanation:
The image shown here is a good illustration of which law?
Answer:
A.) Newton's First Law
Explanation:
I'm pretty sure, I'm sorry if I'm wrong, I just looked it up on G o o g l e
Why do particles with different masses have the same kinetic energy when at the same temperature?
Answer: Because Kinetic energy depends on temperature and not mass
Explanation:
Average kinetic energy is defined as the average of the kinetic energies of all the particles present in a system. It is determined by the equation:
[tex]K.E=\frac{3RT}{2}[/tex]
where K.E = Kinetic energy
R= gas constant
T= temperature in kelvin
It is visible that kinetic energy is dependent on the temperature of the system and not on the mass of the system. Thus particles with different masses have the same kinetic energy when at the same temperature
How did the Hale-Bopp comet get its name?
O The name refers to the comet's shape.
O It was named after the first people to see it.
O A committee of astronomers named it after ancient astronomers.
O The name was at the top of the IAU's comet-naming list
Answer:
it was named after the first people to see it
Explanation: I took the quiz
Hale - Bopp comet get its name after first people to see it.
What is Hale - Bopp comet?Comet is a small body of a solar system, which release gases due to getting hot when passes closer from the sun. It looks like icy illusion structure. Comet - hunter Alan Hale and Thomas Bopp first time spotted a faint comet between Jupiter and Saturn. So, the Hale - Bopp comet get its name after its co - discovers.
Hence, option second is correct i.e. it was named after the first people to see it.
To know more about Hale - Bopp comet, visit the below link:
https://brainly.com/question/22791791
At STP, in the equation C(g) + O2(g) --> CO2(g), one liter of O2 yields how many liters of CO2?
Answer:
3 I think but ask someone else too
Write the equation for the acid dissociation, write the Ka expression, solve for Ht concentration, then do an ICE chart. Put the values into the Ka expression (the one you solved for Ht and find Ht, convert to pH and input that to 2 decimal place. Or use the Henderson-Hasselbalch equation:
pH = pka, + log ( Base/Acid)
Calculate the pH of a buffer solution consisting of 0.39 M HA (Ka = 8.8 x 10^-6) and 0.2 M NaA.
Answer:
The pH of the buffer is 4.77
Explanation:
Using Henderson-Hasselbalch equation we can solve the pH of the buffer:
pH = pKa + log [A⁻] / [HA]
Where pH is the pH of the buffer
pKa is -log Ka = 5.056
[A⁻] = [NaA] = 0.2M
[HA] = 0.39M
Replacing:
pH = 5.056+ log [0.2] / [0.39]
pH = 4.77
The pH of the buffer is 4.77
How are scientists trying to use a plant catalyst to create solar fuels? Someone please answer?
Answer:
plants can be used as fuel because plants can be burned so they compose the plants to make a liquid
I need help ASAP pls
Answer:
A should be the swer n
Explanation:
Determine if the bond between atoms in each example below is nonpolar covalent, polar covalent, or ionic a. H-H b. P-Cl c. F-F d. Na-Br e. N-F f. Mg-O g. C-H h. H-Cl
Answer:
a nonpolar covalent
b polar
c nonpolar
d ionic
e. polar
f. ionic
g polar
h polar
Explanation:
What are some positive and negative things about living near a volcano?
of nitrogen gas)?
How many grams of H2 are needed to produce 71.1 g of ammonia (NH3) (assuming unlimited availability
3 H2+ N2 + 2NH3
Provide the answer with 3 or more significant figures.
Answer:
[tex]m_{H_2}=12.6gH_2[/tex]
Explanation:
Hello there!
In this case, given the reaction:
[tex]3 H_2+ N_2 \rightarrow 2NH_3[/tex]
It is possible to compute the necessary grams of hydrogen which produce 71.1 g of ammonia, given the 3:2 mole ratio and their molar mass as shown below:
[tex]m_{H_2}=71.1gNH_3*\frac{1molNH_3}{17.04gNH_3}*\frac{3molH_2}{2molNH_3} *\frac{2.02gH_2}{1molH_2}\\\\m_{H_2}=12.6gH_2[/tex]
Best regards!
balance kclo3-kcl+02
Which of the following is not something that should be considered when creating a debt payment plan?
a. In general, the larger the debt, the longer you should plan to take to pay it off.
b. Higher interest rates create more cost than lower interest rates on a similar debt.
C. Making a payment larger than required or expected will help pay off the debt sooner.
d. The longer you take to pay off your debt, the more you will be paying in interest and other
fees
Answer:
a. In general, the larger the debt, the longer you should plan to take to pay it off.
When paying off debt consider the interest rates. C., and D. are just facts.
In general, the larger the debt, the longer you should plan to take to pay it off. The correct option is a.
What is debt payment plan?A debt payment plan is a way to pay off debts gradually. It usually entails consistent payments toward the balance due on each loan.
The total amount of debt, interest rates, minimum payments, and the time frame for repayment should all be taken into account while making a debt payment plan.
You can lower the amount of interest you pay over time by making a payment that is greater than what is required or anticipated in order to assist you pay off the debt sooner.
The longer it takes you to pay off your debt, the more vital it is to bear in mind.
In general, when making a debt payment plan, you shouldn't take into account the fact that the debt will take longer to pay off the larger it is.
Thus, the correct option is a.
For more details regarding payment plan, visit:
https://brainly.com/question/13981679
#SPJ6
what is valence electron configuration for group 4A (14)
Answer:
The group 14 elements all have ns2np2 valence electron configurations. All form compounds in which they formally lose either the two np and the two ns valence electrons or just the two np valence electrons, giving a +4 or +2 oxidation state, respectively
Explanation:
Answer:
The group 14 elements all have ns2np2 valence electron configurations. All form compounds in which they formally lose either the two np and the two ns valence electrons or just the two np valence electrons, giving a +4 or +2 oxidation state, respectively.
Explanation:
Determine whether each practice is recommended to keep a micropipette clean and functioning properly.
1. Use a new tip any time you change solutions.
A. Recommended.
B. Not recommended.
2. Turn the micropipette upside down after loading with liquid.
A. Recommended.
B. Not recommended.
3. Save tips after removal to reuse them later.
A. Recommended.
B. Not recommended.
4. Place the micropipette on a rack after using it.
A. Recommended.
B. Not recommended.
5. Place the micropipette on the bench between uses.
A. Recommended.
B. Not recommended.
Answer:
1. A
2. B
3. B
4. A
5. B
Explanation:
1. Recommended. That way cross-contamination is prevented.
2. Not recommended. The inner mechanism of the micropipette should not come in contact with any liquid whatsoever.
3. Not recommended. It contradicts statement 1.
4. Recommended. That way the micropipette remains completely vertical, minimizing the risks of being decalibrated.
5. Not recommended. If it lays on the bench it will be horizontal, thus contradicting statement 4.
Answer:
1. A
2. B
3. B
4. A
5. B
Explanation:
plzzzzzzz help asap its just one question plzzzzz its in the file <3
Answer:
There are 6 atoms of oxygen in 2Ca(NO3)2
To date, scientific tests of astrology have never found that its predictive methods work.
True
False
true______________________
i have to match the word lithosphere to life, sky/air, land and water which one?
Answer:
The answer is air
Explanation:
This is from the web:
"The lithosphere is located below the atmosphere, which is the air that surrounds the planet, and above the asthenosphere."
Hope this helps and answers your question! Have a great day/night!
Explain three types eye protection and their appropriate uses
Answer:
safety glasses, safety goggles, face shield, they protect your eyes from harmful liquids, bright lights
In Universe L , recently discovered by an intrepid team of chemists who also happen to have studied interdimensional travel, quantum mechanics works just as it does in our universe, except that there are four d orbitals instead of the usual number we observe here. Use these facts to write the ground-state electron configurations of the third and fourth elements in the first transition series in Universe L .
Answer:
See explanation
Explanation:
The third element in the first transition series is Vanadium
The fourth element in the first transition series is chromium
Given that we have four d orbitals in universe L instead of five as we have on earth;
The electronic configuration of Vanadium in universe L is;
Ar 3d3 4s2
The electronic configuration of chromium in universe L is;
[Ar] 3d4 4s2
What does cellular respiration do?
Break down sugar and release energy for an
organism to use
Create sugar filled with energy
Deter predators
Form glucose from hydrogen, oxygen, and carbon
:D
help asap
which acide will have more strength
out of two acids of pH
value 2
and 5 why
Ph 2 will ahve more strength due to the fact that its more acidic compared to pH 5.
the lower the number of a pH, the more it is heading towards being acidic, but the higher the number, the more it heads towards being an alkali. here is a ppt i made along time ago. hope it can help you . have a nice day