True or False
A sphere is a group of parts that work together as a whole.
False is the correct answer.
A photon of 498nm was emitted from a silicon atoms. Calculate the energy of all the atomic levels of silicon and show that the atomic levels are quantized.
The Energy of a photon in an atomic level, E = hc / λ
where
h=Planck's constant =6.626 × 10^{−34}Js
c=speed of light=3×10^8m/s
λ = photon's wavelength (metres),
E={6.626×10^{-34}Js × 3× 10^{8}m/s / {498}m/s
E= 3.99×10^{-28}J
Because all the energy levels of electrons in an atom are quantized,and cannot exist on different values of energies between them. So, when an electron moves from one energy level to another, it would release or absorb a specific and same amount of energy. Therefore, the energy of all the atomic levels of silicon must be E= 3.99×10^{-28}J
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A mixture of copper sulfate and water is heated, leaving a residue of copper sulfate in the container. Which method was used to separate the mixture?
A. evaporation
B. chromatography
C. distillation
D. filtration
Evaporation.
Also, it is not set to be a certain letter as for abcd
b. Chlorophenol has three isomers. Draw the skeletal formula for these three isomers and the structural
formula for one of them.
(4 marks)
Answer:
Explanation:
The image ending 1318 is 2-chlorophenol. The image ending 1725 is 3-chlorophenol and the image ending 1917 is 4-chlorophenol
compared to those
5. Electrons farther away from the nucleus in an atom have
closer to the nucleus.
O A. lower energy
OB. higher energy
O C. the same energy
O D. higher or lower energy, depending on the element
Explanation:
higher or lower energy, depending on the element
Answer:
B
Explanation:
Why is it difficult to rub away any carbon atoms from diamonds?
Answer:
because diamond is the allotrope of carbon and diamond is the hardest substance in the world and it's melting point is very very high so it's difficult
HCl reacts with O2 as follows: 4HCl+O2→2Cl2+2H2O When 1.79 g of HCl reacts with 5.68 g of O2 , which statement applies?
the statements that are applicable are the ones that mention HCl being a limiting reactant, or the one that includes that the maximum amount of Cl gas that can be produced is 1.74g
It is difficult to measure the volume of a gas
Answer:
Gases are more difficult to measure than liquids, because measured volumes are highly affected by temperature and pressure. Gas meters measure a defined volume, regardless of the pressurized quantity or quality of the gas flowing through the meter.
Explanation:
It is difficult to measure the volume of agas because measured volumes are highly affected by temperature and pressure.
The temperature of 150 mL of water is 25°C. What must happen for the temperature of the
water to increase to 35°C?
A. Thermal energy must be transferred to the water to increase the average kinetic
energy of the water molecules.
B. Thermal energy must be transferred from the water to decrease the average
kinetic energy of the water molecules.
C. Water must be removed to decrease the thermal energy.
D. More water must be added to increase the thermal energy.
Answer:D
Explanation:
Four bonding pairs around a central atom results in a ________.
Density = 12 g/mL and the Volume = 4 mL. What is the mass?
Answer:
48
Explanation:
12 g/ml * 4 ml = 48
After a scientist has drawn a conclusion, tests the conclusion, and is satisfied with the results,
what is the next step in the scientific process?
A.making a hypothesis
B.experimenting
C.communicating results
D.analyzing data
Answer: B
Explanation:
How far will a dog travel in 8 hours at a speed of 4 meters/hour
What would most likely happen if the kangaroo rats
were killed off and removed from the food chain?
Answer:
Explanation:
The number of cactus plants would increase.
List of choices for questions 20-24: A. (1) CH3MgBr, (2) H3O , (3) CH3MgBr, (4) H3O B. (1) LDA, (2) CH3I, (3) H3O C. (1) CH3MgBr, (2) H3O , (3) NaBH4, (4) H3O D. (1) DIBAH, (2) H3O E. (1) NaOH, heat, (2) SOCl2, (3) CH
Answer:
h30
Explanation:
a volume of L is also equal to
Answer: One-Thousand of a cubic metre
Explanation:
One lire is the Volume of a cube with 10 cm sides
explain the concept of dihyric alcohols
Answer:
An alcohol that contains two hydroxyl groups
is clarity a physical or chemical property?
You go to a convenience store to buy candy and find the owner to be rather odd. He allows you to buy pieces in multiples of four, and to buy four, you need $0.23. He only allows you to do this by using 3 pennies and 2 dimes. You have a bunch of pennies and dimes, and instead of counting them, you decide to weigh them. You have 636.3 g of pennies, and each penny weighs 3.03 g. Each dime weighs 2.29 g. Each piece of candy weighs 10.23 g.
Required:
a. How many pennies do you have?
b. How many dimes do you need to buy as much candy as possible?
c. How much should all these dimes weigh?
d. How many pieces of candy could you buy? (number of dimes from part b)
e. How much would this candy weigh?
f. How many pieces of candy could you buy with twice as many dimes?
a. We have 210 pennies
b. We need 140 dimes to buy as much candy as possible.
c. All these dimes should weigh 320.6 g.
d. We can buy 70 pieces of candy.
e. The total weight of the candies will be 2864.4 g
f. Using 3 pennies and 2 dimes as a pack to buy candies we can not buy more pieces of candy because we would need more pennies.
a. To find the number of pennies we need to divide the total mass of pennies ([tex]m_{t_{p}}[/tex]) by the mass of each one of them ([tex]m_{p}[/tex]):
[tex] N = \frac{m_{t_{p}}}{m_{p}} = \frac{636.3 g}{3.03 g} = 210 [/tex]
Hence, we have 210 pennies.
b. We can find the total number of pieces in multiples of four that we can buy with 210 pennies. To buy one piece we need to use 3 pennies and 2 dimes, so the number of total pieces is:
[tex] 3P = 210 [/tex]
Where P is for pennies
[tex] P = \frac{210}{3} = 70 [/tex]
Hence, we can buy a total of 70 pieces in multiples of four candies.
Now, from this total of 70 pieces, we can use the following number of dimes:
[tex] 2D = 70 [/tex]
Where D is for dimes
[tex] D = \frac{70}{2} = 140 [/tex]
Therefore, we need 140 dimes to buy as much candy as possible.
c. The mass of the total amount of dimes ([tex] m_{t_{d}}[/tex]) is:
[tex] m_{t_{d}} = 140*2.29 g = 320.6 g [/tex]
Hence, all these dimes should weigh 320.6 g.
d. We know that we can buy a total of 70 pieces in multiples of four candies (calculated above).
Then, we can buy 70 pieces of candy.
e. Knowing that each piece is a multiple of 4 candies, the weight of the 70 pieces of candy ([tex]m_{c}[/tex]) is:
[tex] m_{c} = 70*4*10.23 g = 2864.4 g [/tex]
f. Since we can buy pieces in multiple of four candies using 3 pennies and 2 dimes if we have now twice as many dimes, we can not buy more pieces of candy because we would need more pennies.
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convert 6.86 km into m
Hi there!
1 km=1000m
so
6.86 km = 6.86×1000= 6860 m
have a nice day
#YoghurtCup!
A molecule of a compound has 12 atoms of carbon 24 atoms of hydrogen and 6 oxygen atom
What is its empirical formula also write its molar mass and empirical formula mass
Please hel
Describe two methods by which light is produced.
Answer:
gas lamp, led light, laser, inculding cfls andincandescent lights
Max puts cereal in a bowl and pours milk over it. Which term best describes Max’s bowl of cereal?
A. pure substance
B. homogeneous mixture
C. heterogeneous mixture
D. compound
Answer:
Heterogenous
Explanation: Because its not one uniform thing.
The term that best describes Max's bowl of cereal is a heterogeneous mixture.
A heterogeneous mixture is a chemical term that refers to those mixtures in which its components can be distinguished with the naked eye.
One of the distinctive characteristics of heterogeneous mixtures is that the substances that compose them retain their properties and can be separated by physical procedures such as:
FiltrationCrystallizationDecantationDistillationAccording to the above, Max's bowl is an example of a heterogeneous mixture because milk and cereals can be distinguished with the naked eye and these can be separated using a physical procedure.
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In the shorthand notation for a galvanic cell, a double vertical line (A) represents 123) A) a gas B) a cathode C) a salt bridge D) a single phase boundary
Which subatomic particle is important in chemical building and helps determine chemical properties
Explanation:
Since Z is EXPLICITLY determined by the number of protons, massive, positively charged particles, present in the element's nucleus, the proton must be the greatest determinant. Of course, it is the electrons that actually do the chemistry, but Z defines the element.
Is thallium, TI, a solid, liquid, or gas?
Answer:
Thallium is a Solid
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Mark me as Brainliest plz!
:DD
Please help thank you (15 points)
Answer:
D. The sun has less gravitational pull on Pluto because it is farther away.
Is it me or is this year moving very fast?
Does anyone even remember Easter?
Answer:
I think you are moving fast my friend,but i don't remember Easter.
Answer:
yo fr i dont even remember last year christmas
Explanation:
As the human population has grown. Earth's ecosystems and the balance
of natural cycles have been negatively affected. What are some
examples of how the social factors of sustainability (Fig. 1-3) could be
used to help repair environmental damage caused by humans?
40 POINTS I NEEDA ASAP
Write a balanced chemical equation for the following reaction in an acidic solution: Copper metal reacts with aqueous nitric acid to form aqueous copper (II) nitrate, liquid water and gaseous nitrogen monoxide.
Answer:
Cu(s) + 4HNO₃(aq) -> Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)