Answer:
No comparison => John Dalton did NOT postulate an atomic structure.
Explanation:
Dalton's postulates are based upon generalizations of observable phenomena. Micro structure was not proposed. The atomic structure that's accepted in the scientific community evolved from conclusions of ...
Thompson's raisen pudding model => electrons suspended in a positive matrix
Rutherford's shell model => dense positive nucleus surrounded by an electron cloud. (No fine structure postulated)
Bohr Concentric Ring Model => electrons orbiting a positive nucleus in discrete energy levels much like planets orbiting the sun.
Schrodinger - Dirac Quantum Models => electrons occupying specific orbital energy levels as based upon statistical wave mechanics.
The most common experimental technique to perform elemental analysis is combustion analysis, where a sample is burned in a large excess of oxygen and the combustion products are trapped in a variety of ways. A 99.99% pure, 0.4808 g sample containing only carbon, hydrogen, and nitrogen is subjected to combustion analysis, resulting in the formation of 0.6859 g CO2, 0.6973 g H2O, and 0.4646 g NO. What is the empirical formula of the sample
Answer:
C₂H₅N₂
Explanation:
In the combustion analysis, all NO comes from the nitrogen of the sample, that means:
Moles NO = Moles N in the sample
In the same way:
Moles CO2 = Moles C in the sample
Moles H2O = 1/2 moles H in the sample
To solve this problem we must convert the mass of each gas to moles in order to find the moles of each atom. The empirical formula is the simplest whole number ratio of atoms presents in the molecule:
Moles NO = N -Molar mass: 30g/mol
0.4646g * (1mol / 30g) = 0.01549 moles N
Moles CO2 = C -Molar mass: 44.01g/mol-
0.6859g * (1mol / 44.01g) = 0.01559 moles C
Moles H2O = 1/2moles H -Molar mass: 18.02g/mol-
0.6973g * (1mol / 18.02g) = 0.03870 moles H
The ratio of atoms is -Dividing in the low number of moles = moles N-:
C = 0.01559 / 0.01549 = 1
N = 0.01549 / 0.01549 = 1
H = 0.03870 / 0.01549 = 2.5
Twice this ratio of atoms -Because empirical formula must be given only with whole numbers:
C = 2
N = 2
H = 5
The empirical formula is:
C₂H₅N₂What's a house hold item that has nuclear energy
Answer:
Electricity, Weapons, Medicine · Food Treatments, ect.
Dawn is comparing how different animals move and the structures they use to move. She made the table shown below.
Animal Method of movement Structures used for movement
panther walks legs and feet
parrot flies wings
shark swims
Which structure completes the table for the shark?
eyes and brain
skin and scales
tail and fins
teeth and jaws
Answer:
tail and fins
Explatanation:
What is the fundamental different between combustion and nuclear reaction
Answer:
Nuclear reactions involve a change in an atom's nucleus, usually producing a different element. Chemical reactions, on the other hand, involve only a rearrangement of electrons and do not involve changes in the nuclear.
If 2.00 moles of H2 and 1.55 moles of Oz react how many moles of H20
can be produced in the reaction below?
2 H2(g) + O2(g) → 2 H2O(g)
Only animals and not plants can adapt to their environment true or false
Answer:
true
Explanation:
np have a good day brainliest?
Question 2
1 pts
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A compound is 31.1 % S, the rest is chlorine. The compound has a molecular mass of 205.94 amu.
What is its molecular formula?
Explanation:
its hard to explain unless we know what the question fully asks..
Imine formation from an aldehyde and an amine proceeds reversibly under slightly acidic conditions. The reaction is reversible due to acid-catalyzed hydrolysis of the imine. Imine formation generates an equivalent of water. Given these facts, explain why the imine can be isolated from the reaction mixture.
Answer:
Imine can be isolated from the reaction mixture as water is continuously removed from the reaction chamber
Explanation:
In this reaction, a non -aqueous solvent is not used (not mentioned in the question). Thus, we can say that there is continuous removal water under suitable reacting conditions and hence the imine formed is left behind.
heat would best be transferred by conduction between
A. a candle and the air
B. an oven and a glass dish
C. a stove and a copper pot
D. water and a wooden spoon
Answer:
C. or B.
Explanation:
The reason I chose c best, is when your cooking something with a pot with food in it max heat in about 5 minutes, the handle starts to get warmer every minute. This is conduction, where the heat transfers from the very bottom all the way to the very edge of something that is heated at a certain temperature.
How many grams of hydroxide pellets, NaOh are required to prepare 50.0ml of a 0.150 M solution ?
A.0.300g
B.3.00g
C.2.00g
D.200.g
E. 0.025 M
If I have 7.0 x 10^24 formula units of magnesium chloride, how many grams of chlorine would I have?
Answer:
824 g
Explanation:
First we convert 7.0 x 10²⁴ formula units of magnesium chloride (MgCl₂) into moles, using Avogadro's number:
7.0 x 10²⁴ formula units ÷ 6.023x10²³ formula units/mol = 11.62 mol MgCl₂There are two Cl moles per MgCl₂ moles, meaning that we have (2 * 11.62) 23.24 moles of Cl
Finally we convert 23.24 moles of chlorine into grams, using chlorine's molar mass:
23.24 mol * 35.45 g/mol = 824 gA 1.4639-g sample of limestone is analyzed for Fe, Ca, and Mg. The iron is determined as Fe2O3 yielding 0.0357 g. Calcium is isolated as CaSO4, yielding a precipitate of 1.4058 g, and Mg is isolated as 0.0672 g of Mg2P2O7. Report the amount of Fe, Ca, and Mg in the limestone sample as %w/w Fe2O3, %w/w CaO, and %w/w MgO
Answer:
A) w/w % of Fe - 2.44%
B) w/w % of Mg - 4.590%
C) w/w % of Ca - 96%
Explanation:
A) w/w % of Fe in limestone as Fe2O3 = (Mass of Fe2O3 /Mass of limestone) x 100
0.0357/1.4639 X 100
= 2.438 =2.44
B) w/w % of Mg in limestone as Mg2P2O7 = (Mass of Mg2P2O7 /Mass of limestone) x 100
= 0.0672/1.4639 X 100
= 4.590
C) w/w % of Ca in limestone as CaSO4 = (Mass of CaSO4/Mass of limestone) x 100
= 1.4058/1.4639 X 100
= 96
Answer:Fe =1.71% Ma=0.99% Ca=28.24%
Explanation:
I will mark brainliest
What kind of weather forms with an occluded front?
Answer:Occluded fronts usually form around areas of low atmospheric pressure. There is often precipitation along an occluded front from cumulonimbus or nimbostratus clouds. Wind changes direction as the front passes and the temperature either warms or cools.
Explanation:
Calculate the pH of a solution with [H+] = 1.8 x 10^-5 M
Answer:
4.74
Explanation:
pH= -log[H+]
pH= -log(1.8 x 10^-5)= 4.74
Students can demonstrate reflection by doing which of the following?
A Warming metal under a heat lamp.
B. Observing their own image in still water.
C. Enlarging an image using a hand lens.
0
D. Measuring a shadow made by the Sun.
Answer:
a
Explanation:
select two correct answers
Answer:
D and E
Explanation:
The other answers don't support steel, they support iron or are supporting both, and the question is why steel alloys are more often used
C supports both
B supports how iron's strength
A supports iron being easily shaped and bent
hope this helps
Because a water molecule has a negative end and a positive end it displays?
Answer:
A water molecule displays polarity by having negative and positive ends. Due to this charge difference, a water molecule is called a dipole.
Explanation:
How many grams of CuSO4 are required to make a 5.0 ml solution that has a concentration of 400 mg/ml?
Answer: molecular weight of CUSO4 or grams. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles CUSO4, or 346.10221 grams. Note that rounding errors may occur, so always check the results.
Explanation:
A 31.25 mL aliquot of weak base that has a concentration of 0.683 M will be titrated with 0.434 M HCl. Calculate the pH of of the solution upon neutralization of half of the weak base. The Kb of the base is 1.5×10-6.
Answer:
pH = 8.18
Explanation:
The weak base, X, reacts with HCl as follows:
X + HCl → HX⁺ + Cl⁻
Where 1 mole of X with 1 mole of HCl produce 1 mole of HX⁺ (The conjugate acid of the weak base).
Now, using H-H equation for bases:
pOH = pKb + log [XH⁺] / [X]
Where pOH is the pOH of the buffer (pH = 14 -pOH)
pKb is -log Kb = 5.824
And [X] [HX⁺] are the molar concentrations of each specie
Now, at the neutralization of the half of HX⁺, the other half is as X, that means:
[X] = [HX⁺]
And:
pOH = pKb + log [HX⁺] / [X]
pOH = 5.824 + log 1
pOH = 5.824
pH = 14-pOH
pH = 8.183. Convert the word equations below to symbolic:
Sodium + chlorine sodium chloride
• Calcium + bromine ---- calcium bromide
• Potassium + water → potassium hydroxide + hydrogen
ot
Answer:
1)2Na + Cl2 ----> 2NaCl
2)Ca + Br2 ---->CaBr2
3)K + H2O -----> KOH + H2
Write a scientific explanation that answers the following question: Is matter conserved during a
chemical reaction in both closed and open systems?
Claim:
Evidence:
Reasoning:
Answer:
Matter is conserved during all chemical reactions because matter cannot be created or destroyed.
Explanation:
please answer asap!
What is the molarity of a KOH solution if 200 ml of the solution contains 0.6 moles KOH?
a. 0.3 M
b. 0.6 M
c. 3.0 M
d. 6.0 M
Identify the Lewis base in this balanced equation: 6 upper H subscript 2 upper O plus UPper C r (upper H subscript 2 upper O) subscript 6 superscript 3 plus. H2O Cr3+ Cr(H2O)63+
The Lewis base that we can see in the equation is [tex]H_{2} O[/tex]
What is the Lewis base?We have to bear in mind that the Lewis base is the substance that is able to donate a pair of electrons. The substances that is able to accept the pair of electrons is what we call the Lewis acid.
The Lewis acid must possess a space for the addition of an electron pair while the Lewis base would have to be a specie that has a lone pair of electrons or has a negative charge. Thus the water molecule would serve as a Lewis base in this regard.
Learn more about Lewis base;https://brainly.com/question/15570523
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Answer:
6 upper H subscript 2 upper O plus UPper C r (upper H subscript 2 upper O) subscript 6 superscript 3 plus.
✔ H2O or A.)
Cr3+
Cr(H2O)63+
Draw a structural formula for the organic product formed by treating butanal with the following reagent: NaBH4 in CH3OH/H2O You do not have to consider stereochemistry. You do not have to explicitly draw H atoms. Do not include lone pairs in your answer. They will not be considered in the grading. Include counter-ions, e.g., Na , I-, in your submission, but draw them in their own separate sketcher. Do not draw organic or inorganic by-products.
Answer:
Please find the solution in the attachment file.
Explanation:
IM GIVING 100 POINTS FOR WHOEVER ANSWERS THIS PLS HELP determine which heat transfers below are due to the process of conduction. I) You walk barefoot on the hot street and it burns your toes. II) When you get into a car with hot black leather seats in the middle of the summer and your skin starts to get burned when you touch the seats. III) A flame heats the air inside a hot air balloon and the balloon rises. IV) A boy sits to the side of a campfire. He is 10 feet away, but still feels warm. Question 1 options: I & II III & IV I, II, & IV II, III, IV
Answer:
I and II
Explanation:
Hi can someone please help me with this. I would really appreciate it. It’s kind of urgent. Thank u so much!
Answer:
a) The system is in equilibrium
b) No other force is acting on the system
Explanation:
a) The forces in a system is balanced until and unless there is equal and opposite force acting on the system. In this image the upward force is equal to the downward force on the book and the table and hence it is in equilibrium
b) An object which is in static mode, produces downward force because of weight and in response to that a normal reaction is produced in upward direction. Apart from these two forces, no other force is acting on this book and table system.
Why does understanding the Rock Cycle help us to plan living on the ocean? answer before it's too late!
Answer:
Learning the rock cycle and understanding the processes involved helps all of us. This is how soil forms, through the breakdown of rocks. We need soil to survive—imagine trying to grow vegetables without it. This is an immediate connection to the food chain
What is the mass in grams of precipitate formed when 250.0 mL of 0.360 M ZnCl₂ is mixed with excess KOH in the following chemical reaction?
ZnCl₂ (aq) + 2 KOH (aq) → Zn(OH)₂ (s) + 2 KCl (aq)
Answer:
8.95 g
Explanation:
ZnCl₂ (aq) + 2 KOH (aq) → Zn(OH)₂ (s) + 2 KCl (aq)First we calculate how many ZnCl₂ moles reacted, using the given concentration and volume:
250 mL / 1000 = 0.250 L0.360 M * 0.250 L = 0.090 mol ZnCl₂Then we convert ZnCl₂ moles into Zn(OH)₂ moles [ Zn(OH)₂ is the precipitate, as it is the solid]:
0.090 mol ZnCl₂ * [tex]\frac{1molZn(OH)_2}{1molZnCl_2}[/tex] = 0.090 mol Zn(OH)₂Finally we convert 0.090 Zn(OH)₂ moles into grams, using its molar mass:
0.090 mol Zn(OH)₂ * 99.424 g/mol = 8.95 gThe mass of a substance is the product of the molar mass and the moles of the substance. The mass of precipitate formed in the reaction is 8.95 gm.
What is Mass?The mass of the substance is the weight of the compound or the molecule present in the sample.
The balanced chemical reaction is shown as:
[tex]\rm ZnCl_{2} (aq) + 2 KOH (aq) \rightarrow Zn(OH)_{2} (s) + 2 KCl (aq)[/tex]
Given,
Volume (V) of zinc chloride = 0.250 L
Molarity of zinc chloride (M) = 0.360M
Moles of zinc chloride are calculated as:
[tex]\begin{aligned} \rm moles &= \rm molarity \times volume \\\\&= 0.360 \times 0.250\\\\&= 0.090 \;\rm mol\end{aligned}[/tex]
Moles of zinc hydroxide from zinc chloride are calculated as:
[tex]0.090\;\rm mol \; ZnCl_{2} \times \dfrac{ 1\;\rm mol \;\rm Zn(OH)_{2}}{1\;\rm mol\; ZnCl_{2}} = 0.090 \;\rm mol[/tex]
Mass is calculated as:
[tex]\begin{aligned} \rm mass &= \rm moles \times molar \; mass\\\\&= 0.090 \times 99.424 \\\\&= 8.95 \;\rm gm\end{aligned}[/tex]
Therefore, 8.95 gm precipitate is formed.
Learn more about mass here:
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2. A plant growing in response to the sunlight.
A.Gravitropism
B.Phototropism
C.Thigmotropism
D.Hydrotropism
Answer:
phototropism
Explanation:
since photo is (light?
Help (also tell me what the phenotype and genotypes are)
Answer:
genotype are the organism's hereditary information for example DNA
phenotype are the organism's physical characteristics for example your eyes or hair
or how your nose looks