Answer:
Dmitri Mendeleev
Explanation:
Dmitri Mendeleev a Russian Chemist arranged elements on the periodic table according to their atomic mass. He used this arrangement to predict some of the properties of the missing element.
Dmitri Mendeleev around 1869 described the periodic table. The table was based on the periodic law which states that "chemical properties of elements are a periodic function of their atomic weights". In the Mendeleev table, elements are arranged by atomic weights with recurring properties in a periodic manner.5 grams of KClO3 is dissolved in 100 g of water at 30 °C. How
many more grams of Kcloz Should be added in order to create a
saturated solution?
A 5 grams
B
10 grams
С
15 grams
D
1 gram
Answer:
15 grams
Explanation:
Which choices are layers of the atmosphere? Select the five correct answers. Mesosphere Danosphere Croposphere Stratosphere Thermosphere Exosphere Meteorosphere Troposphere
Answer:
Mesosphere
Stratosphere
Thermosphere
Troposphere
Exosphere
Explanation:
The exosphere refers to the farthest region of the atmosphere that gradually fades into space.
The troposphere is the lowest layer of atmosphere. It is the layer where weather changes occur.
The thermosphere is right above the mesosphere but just below the exosphere. It is the layer where photoionization/photodissociation of molecules occurs thereby creating ions. This largely owes to interaction of molecules in this layer with ultraviolet radiation.
The stratosphere is composed of gases. Prominent among them is ozone which serves as a blanket against the sun's ionizing radiation.
The mesosphere lies above the stratosphere but just below the thermosphere. Temperature decreases steadily with height in the mesosphere.
The 5 layers of the atmosphere are the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
The atmosphere has been consisted of the 5 layers that protect the earth. The layers have been present at the height that and each layer has consisted of different constituents.
The layers of the atmosphere can be described as:
Exosphere: It has been the layer farthest to the earth and has been consisted of space.Thermosphere: It has been layer followed by the exosphere. The layer has been consisted of satellites and rockets.Mesosphere: The layer has been at the height of 50-90 km and has been consisted of meteors, stars, and meteorically rockets.Stratosphere: The layer has been at the 12-50 km height and has been consisted of radio-sounds and waves.Troposphere: The innermost layer of the atmosphere. It has consisted of clouds, planes, and balloons.The 5 layers of the atmosphere are the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
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*(d) Impure copper can be purified using electrolysis.
In this electrolysis
• the anode is made of impure copper
• the cathode is made from pure copper
• the electrolyte is copper sulfate solution.
The apparatus at the start of the experiment is shown in Figure 7.
During the electrolysis three observations are made
• the sizes of both the anode and the cathode change
• a solid appears directly beneath the anode
• the colour of the copper sulfate solution does not change.
Explain all three observations.
i will give u brainliest if u get it right
Answer:
iaiaiaiiaiaiaaiiaiaiaiaiaiia
Explanation:
babababbabahahahhahahahhahahahhahahahahahhahahahahahhahahhahahyayoenbshiwibbshhjjahjb bjkkoankokokkoekormkrokrkrk
The sizes of both the anode and the cathode change because the copper ions travel from the anode to the cathode. Therefore, a solid copper appears directly beneath the anode. The number of copper ions remains the same so there is no color in the CuSO₄ solution.
What is electrolytic refining?Electrolytic refining can be described as a process of refining metal, especially copper by the process of electrolysis. During electrolysis, impure metal is used as the anode and pure metal as the cathode.
The pure metal is formed at the cathode when the electrical current is applied by dissolving impure metal at the anode.
In copper refining, a block of impure copper is taken as an anode. CuSO₄ is used as a graphite-coated electrolyte along with pure copper, as a cathode. In electrolysis, CuSO₄ divides into a positive ion of copper (Cu²⁺) and sulfate (SO₄²⁻). The copper ion (Cu²⁺) travels made of pure copper where it absorbs the electrons from the cathode.
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According to Dalton's theory, is it possible to convert atoms of one element into atoms of another? Explain.
please help
Answer:
No, it's not possible to change the atoms into a different element.
Explanation:
No, because rule four of his theory says that change cannot occur
Si un operador debe elevar una carga de 100 Kg. ¿Con cuál de las siguientes máquinas simples va a realizar menor esfuerzo? Justifique analíticamente. a) Plano inclinado de 30° sin rozamiento. b) Palanca de primer género con un brazo de potencia de 1 mts y brazo de resistencia de 25 cm. C) Aparejo factorial con 3 poleas móviles. d) Torno con una manivela de 50 cm y el diámetro del tambor de 15 cm.
Answer:
?
Explanation:
What child do parents dislike the most
Oldest Child
Middle Child
Youngest Child
Answer:
Oldest
Explanation:
toxicity
Answer:
Oldest
toxicity
Explanation:
1-Convert the following to moles:
1.5 X 10^23 atoms of Carbon
Answer:
0.249087
Explanation:
1.5 x 10^23 atoms x 1 mole / 6. 022 x 10^23 atoms
= 0.249087
15.
Which species contains 16 protons, 17 neutrons and 18 electrons?
a. 325
b. 3382-
d. 3592-
C. 345
tug of war results in one team pulling another team arcoss the line this is an example of .
A action forces
B reaction forces
C balanced versus
D unbalanced forces
please help me :)
Answer:
It's d love
Explanation:
In which option do all three particles have the same electronic configuration?
And the same number of neutrons? (7N , 8O , 9F ,10Ne , 12Mg)
(a) 15N3- 16O2- 19F-
(b) 18O2- 19F- 20Ne
(C) 19F- 20Ne 23Na+
(d) 22Ne 23Na 24Mg2+
b. ₈¹⁸O²⁻ , ₉¹⁹F⁻ , ₁₀²⁰Ne
Further explanationThe Atomic Number (Z) indicates the number of protons and electrons in an atom of an element.
Atomic number = number of protons = number of electrons ⇒ neutral number
Atomic mass is the sum of protons and neutrons
Atomic Number (Z) = Atomic mass (A) - Number of Neutrons
₈¹⁸O²⁻Atomic mass = 18
Atomic number = 8 , gain 2 electron ⇒ total 10 electrons
Configuration : 1s², 2s², 2p⁶ (10 electrons)
Neutrons : 18 - 8 = 10
₉¹⁹F⁻Atomic mass = 19
Atomic number = 9 , gain 1 electron ⇒ total 10 electrons
Configuration : 1s², 2s², 2p⁶ (10 electrons)
Neutrons : 19 - 9 = 10
₁₀²⁰NeAtomic mass = 20
Atomic number = 10
Configuration : 1s², 2s², 2p⁶ (10 electrons)
Neutrons : 20 - 10 = 10
Liquid octane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 1.1 g of octane is mixed with 1.04 g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction. Round your answer to significant digits.
compare and contrast the similarities and differences between passive and active transport
please help me will mark brainly
Write a scientific explanation that explains how modern whales differ from their ancient ancestors THIS IS A CER so can i get a claim evidence and reasoning
Answer:
Modern whales evolved by natural selection over long time periods through descent from common ancestors
Explanation:
According to the evolutionary theory proposed by Darwin, natural selection is a biological process by which organisms adapt and change in response to their environment. In this case, ancient whales that were better suited to environmental conditions survived and produced more offspring than non-adapted individuals. In consequence, predominant adaptive traits observed in modern whales were favored by natural selection in the past, while unsuccessful phenotypes progressively disappeared.
Please respond this is very important!
Giving a lot of points!
Answer:
a
Explanation:
13. Explain why changes in the concentrations of the
reactants and products at equilibrium have no effect
on the value of the equilibrium constant.
Answer:
It is temperature dependent only
Explanation:
For any system in equilibrium, the molar concentration of all species on the right hand side are related to the molar concentrations of those at the left side by a constant known as the equilibrium constant.
The equilibrium constant is a constant at a given temperature. The constant is temperature dependent only. It is not dependent on the values of concentration or pressure of a system.Match the following parts of the earth with the correct definition: Definitions: 1. Solid, outer layer of the earth 2. Layer between the crust and the core 3. Semi-liquid region directly beneath the crust 4. Made of iron and nickel 5. The water covering the surface of the earth
Words: Mantle, Core, Crust, Hydrosphere, Asthenosphere
Answer:
1) crust
2)mantle
3) asthenosphere
4)core
5) hydrosphere
Explanation:
Hope this helps, Let me know if i am wrong( i dont think i am but, yeah...), OH! and GOOD LUCK! :D ;P.
A vessel of capacity 400 cc filled with chlorine under 80 cm is connected by a narrow tube and stopcock with another vessel of capacity 250 cc filled with nitrogen under 100 cm. what will be the pressure when the stopcock is opened?
Answer:
The pressure when the stopcock is opened is opened is 87.783 cm
Explanation:
The given parameters of the question are;
The volume of the vessel of chlorine = 400 cc
The pressure of the vessel of chlorine = 80 cm
The volume of the vessel of chlorine = 250 cc
The pressure of the vessel of chlorine = 100 cm
Daltons law of Partial Pressures states that the total pressure exerted by a volume of a mixture of gases is equal to the partial pressures exerted by the individual gases in the mixture with respect to the given volume
Therefore;
The total volume of the mixture = 400 cc + 250 cc = 650 cc
The partial pressure exerted by the chlorine gas in the total volume is given by Boyles law as follows;
P₁·V₁ = P₂·V₂
P₂ = P₁·V₁/V₂
Where;
P₁ = 80 cm = The pressure in volume V₁ = 400 cc
P₂ₓ = The partial pressure of chlorine in volume V₂ = 650 cc
Substituting, we have;
P₂ₓ = 80 × 400/650 ≈ 49.321 cm
Similarly, the partial pressure exerted by the nitrogen gas in the total volume is given by Boyles Law as follows;
P₂ₐ = P₁·V₁/V₂
Where;
P₁ = 100 cm = The pressure in volume V₁ = 250 cc
P₂ₐ = The partial pressure of nitrogen in volume V₂ = 650 cc
Substituting, we have;
P₂ₐ = 100× 250/650 ≈ 38.462 cm
The pressure of the combined gas, P, when the stopcock is opened is opened is given by Dalstons Law of partial pressure as P = P₂ₐ + P₂ₓ
Therefore, the pressure, P when the stopcock is opened is opened = 49.321 cm + 38.462 cm = 87.783 cm
10) Air masses are different in many ways. Which of these is NOT different?
a) Atmospheric pressure
b) Temperature
c) Ratio of oxygen/nitrogen
d) Moisture contents
Answer:D. Ratio of oxygen/nitrogen
Explanation: the ratio will never change no matter the air pressure!
In the titration of acetic acid, CH3COOH, a 0.20 M solution of NaOH is used. A volume of 15.00 mL of CH3COOH solution is
titrated. If it takes a total of 24.55 mL of NaOH solution to reach the equivalence point, what is the molar concentration of the
CH3COOH solution?
Answer:
naci
Explanation:
The molar concentration of the CH₃COOH soluttion is 0.33 M
We'll begin by writing the balanced equation for the reaction. This is given below:
CH₃COOH + NaOH —>CH₃COONa + H₂O
From the balanced equation above,
The mole ratio of the acid, CH₃COOH (nA) = 1
The mole ratio of the base, NaOH (nB) = 1
From the question given above, the following data were obtained:
Volume of acid, CH₃COOH (Va) = 15 mL
Molarity of base, NaOH (Mb) = 0.2 M
Volume of base, NaOH (Vb) = 24.55 mL
Molarity of acid, CH₃COOH (Ma) =?MaVa / MbVb = nA/nB
(Ma × 15) / (0.2 × 24.55) = 1
(Ma × 15) / 4.91 = 1
Cross multiply
Ma × 15 = 4.91
Divide both side by 15
Ma = 4.91 / 15
Ma = 0.33 MTherefore, the molar concentration of the acid, CH₃COOH is 0.33 M
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If the reaction begins with 12.0 grams of O2 how many grams of NO2 will be produced given the following equation: 2 NO + O2 --> 2 NO2
Answer:
69g
Explanation:
Given reaction expression:
2NO + O₂ →2 NO₂
Unknown:
Mass of NO₂ produced = ?
Solution:
To solve this problem, let us use the mole concept. We solve from the known to the unknown
In this regard, find the number of moles of O₂ given;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of O₂ = 2(16g/mol) = 32g/mol
Number of moles = [tex]\frac{12}{16}[/tex] = 0.75mole
From the balanced reaction equation;
1 mole of O₂ will produce 2mole of NO₂;
0.75 mole of O₂ will produce 1.5mole of NO₂
Therefore, mass of NO₂;
Mass of NO₂ = number of moles x molar mass
Molar mass of NO₂ = 14 + 2(16) = 46g/mol
Molar mass of NO₂ = 1.5 x 46 = 69g
Which ocean borders Africa on the western coast?
pls answer for 20 coiins
Answer:
indian ocean
Explanation:
If 18 grams of oxygen reacts completely with 4 grams of hydrogen, we would expect how many grams of water?
A.) Less than 22 grams because some mass is lost in the reaction
B.) More than 22 grams because the oxygen gains mass during the reaction
C.) 22 grams because mass cannot be created or destroyed
D.) There is no way to tell from this information.
Answer: 22 grams because mass cannot be created or destroyed
Explanation: I just took the test
Answer:
C.) 22 grams because mass cannot be created or destroyed
Explanation:
Water is polar and toluene is non-polar. The solution that forms will be...
A)hydration shell
B)miscible
C)supersaturated
D)immiscible
Answer:
c supersaturated
Explanation:
hope it helps tell me if i m wrong
Scientist looking for new substances in plants grind up the plants with methanol. This solvent dissolves many plant compounds. However, methanol is flammable and toxic (especially if the vapour is inhaled). Large crystals can be made to help scientists work out what the compounds are made of. Explain how you would make plant-compound crystals using methanol.
Answer:
See explanation
Explanation:
Crystals can be made from methanol by recrystallizing the plant extract from methanol.
The methanol/water system is heated rapidly using a hot plate and the plant extract dissolves in the heating solution until a clear solution is obtained.
The solution is now cooled rapidly. The interior of the flask used for the re crystallization may even by scratched to assist the quick formation of crystals. Large crystals of plant compounds may be obtained using this method. This process should be carried out in a fume hood because of the toxicity of methanol.
Protective clothing can be made from rubber or plastic, because they are good ______________________; they don't allow the flow of electrical charges.
Group of answer choices
circuits
conductors
insulators
Answer: Materials that do not allow electricity to pass easily through them are called insulators. Rubber, glass, plastic, and cloth are poor conductors of electricity. This is why electrical wires are covered in rubber, plastic, or cloth.
Explanation: I hoped that helped plzz mark me as brainliest!
Which of the following is NOT true about relative dating?
Question 4 options:
it uses radioactivity to get a more exact age of a fossil
it uses the nearby rock layers.
It finds the approximate age of fossils.
It uses fossils to help pinpoint the ages of rocks.
help me its wotrth 60 give me thr right awnser or i fail the grade
Answer:
It uses fossils to help pinpoint the ages of rocks.
Explanation:
Radiocarbon dating can not be used to determine the age of rocks.
Carbon dating works well only for objects that are less than 50,000 years. Most rocks are far older than that. Over time, carbon-14 decays gradually into nitrogen. Hence, we can not really use radiocarbon dating to determine the absolute age of a rock sample since the carbon-14 in the fossils of ancient rock samples may have completely decayed.
Which process releases energy that eventually produces lightning in the thunderstorm?
Answer:
Answer: B. Water condenses to form clouds.
Explanation:
When the moisture condenses, this results in the release of energy. The energy causes the air to be warm and results in the rise of air in the upper atmosphere. This process results in the instability in the atmosphere and cumulonimbus clouds are formed. These clouds support lightening during a thunderstorm.
which of these processes are chemical reaction
Answer:
I don't think u finished the question -
Na2o + h2so4 ———> na2so4 + h2o
Can anyone balance this please!!??
Answer:
The equation is already balanced. There's an equal number of materials on each side of the equation.