Dalton was a chemist who discovered the “law of multiple proportion” in chemical reaction in early nineteenth century. For example, element of tin, he observed, interacted with oxygen to produce two different masses but in proportion 1:2. (Now, this is known to correspond to the formation of tin-monoxide and tin-dioxide, with one and two atoms of oxygen, respectively.)
From such and related studies, he proposed his theory of chemical elements: (a) that all elements are composed of ‘atoms’, the hypothetical indivisible constituents of matter of the ancient Greek thinkers, like, Democritus, and (b) that the elements differ from one another due to the atoms of different masses and sizes that constitute an element.
The modern theory of chemistry says that an element consists of an atom that consists of a heavy nucleus with positively charged ‘protons’ (and most often also the neutral particles called ‘neutrons’) at its center and, an equal number of negatively charged (and much lighter) ‘electrons’, distributed around it in discrete energy shells. Further, the elements differ from one another by the number of positively charged protons in their nucleus, the so-called atomic number, Z, of an atom. Finally, molecules are formed as well as chemical reactions take place, through the exchange or transfer of the electron(s) in the outermost shells of the reacting atoms (and/or molecules).
Which of the following is the final stage of a low mass star? *
1 point
stages of mitosis in order
Answer:
nucleus formed
prophase
metaphase
anaphase
telophase and cytokinesis
electron configuration of silver
Answer:
[Kr] 4d10 5s1 or 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s1
What is the main difference between a chemical and a physical change? PLEASE HELP ASAP
Answer:
In a chemical change the nature of the substance changes and it is transformed, for example when a piece of wood is burned, the carbon is being transformed into carbon dioxide. A physical change is one where the nature of matter does not vary.
I hpoe help you.
Answer:
physical changes only change the appearance of a substance not it's chemical composition .chemical changes change the substance with a new chemical formula
Explanation:
What did the Bohr model assume about the motion of electrons?
A. All electrons move in a circular orbit around the nucleus.
O
B. Electrons do not have a specific path around the nucleus.
OC. All electrons move in a single cloud layer around the nucleus.
D. Electrons always remain in the same location around a nucleus.
Answer:
A
Explanation:
THAT'S THE ANSWER EYEUSKSBAW
List the different sizes of sediment.
Answer:
Smallest to Largest:
Clay is smaller then 1/125 mm
Silt is 1/256- 1/16 mm
Sand is 1/16-2 mm
Pebble is 2-64 mm
Cobble is 64-256 mm
Boulder is greater then 256 mm
Explanation:
What evidence suggests that four-legged animals came from fish?
Answer:
Paleontologists have uncovered new fossils from Tiktaalik roseae, which, while still a fish, is considered a transitional fossil that also has traits common to the first four-footed animals. This more complete picture of Tiktaalik suggests that the creature had strong, mobile hind fins.
Explanation:
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what happens to the molecules as water freezes PLS HELP THIS IS DO TODAY
During freezing, water molecules lose energy and do not vibrate or move around as vigorously. This allows more stable hydrogen-bonds to form between water molecules, as there is less energy to break the bonds. ... Thus water expands as it freezes, and ice floats atop water.
When water molecule freezes, the water molecules have slowed down enough that their attractions fixed them into fixed positions.
What do you mean by freezing ?The term freezing is defined as a phase transition where a liquid converted into a solid when its temperature is lowered below its freezing point.
The freezing point is the temperature at which a liquid turns solid. In the freezer, for example, water-filled ice cube trays.
Water molecules freeze in a hexagonal pattern, with molecules further apart than when the water was liquid. It is worth noting that the molecules in ice would be vibrating.
Thus, When water freezes, the water molecules slow down to the point where their attractions arrange them into fixed positions.
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What questions might remain that will one day be answered by new technology?
Answer:
Can we find a safe cure for cancer?
Explanation:
pls mark brainliest
Which of the following elements are characterized by having full outermost s and p
orbitals?
F. Period 7
G.
Group 8A
H.
Inner transition elements
J.
Periods 4, 5, and 6
Answer:
Group 8A
Explanation:
Group 8A elements are characterized by having full outermost s and p orbitals. These elements are also known as the noble gases or inert gases. They occupy the last group on the periodic table.
They are known to have an outer shell configuration of ns² np⁶The configuration reveals that atoms of all the elements have completely filled orbitals in their outer shell sublevels. This accounts for the non-reactivity of elements in this group. Most of the elements in the group have high ionization energy and very low electron affinity values.Some of the elements in this group are Neon, Argon, Krypton, Xenon, and Radon.
When many earthquakes are studied, there is another common pattern that emerges: a "Shadow Zone". This is an area, for any earthquake, on the Earth where direct S-waves don't arrive at all and P waves are refracted. What do you think causes these P waves to be refracted? *
Answer:
Sudden decrease in the velocity at the boundary.
Explanation:
The shadow zone is the zone of the earth from angular distances of 104° to 140° from a known earthquake that does not directly receive any P waves. Now, this shadow zone occurs as a result of S waves getting stopped completely by the liquid core and the P waves being refracted by the liquid core.
From earlier seismic discoveries, this boundary which is the shadow zone that does not directly receive any P-waves was found to be due to the fact that the P-waves were refracted inwards as a result of the sudden decrease in velocity at the boundary.
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how many atoms in a sugar cube
Answer:
Sugar is made up of carbon, hydrogen and oxygen atoms. It's the way these atoms are connected that makes each type of carbohydrate different. In each molecule of table sugar there are: 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms.
Explanation:
What’s a prefix for -4?
A: cuatra
B:quater
C:-tetra
D:-tretis
the making of ice cubes is an endothermic reaction
Answer:
no
Explanation:
it is not endothermic reaction
For an object that has a volume of 24.5 mL and a mass of 102g, calculate the density of the object
Answer:
The answer is 4.16 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass = 102 g
volume = 24.5 mL
We have
[tex]density = \frac{102}{24.5} \\ = 4.163265306...[/tex]
We have the final answer as
4.16 g/mLHope this helps you
Express 749 000 000 in scientific notation,
Answer:
7.49 × 108
Explanation:
Scientific notation is a way to express numbers in a form that makes numbers that are too small or too large more convenient to write. It is commonly used in mathematics, engineering, and science, as it can help simplify arithmetic operations. In scientific notation, numbers are written as a base, b, referred to as the significant, multiplied by 10 raised to an integer exponent, n, which is referred to as the order of magnitude:
how many atoms are in CaCI2
Answer:
4
Explanation:
bc Ca is 1 C is one L is two
The transition metals (with the exception of Zn, Cd and Hg) are very much hard and have low volatility. Why Zn ,Cd and Hg has low melting points. (a) These have all their electrons paired. (b) These have maximum number of unpaired electrons. (c) These have very strong metallic bonding. (d) These have more metal-metal bonding.
Answer:
Zn ,Cd and Hg has low melting points because - These have all their electrons paired.
Explanation:
These have all their electrons paired -: All the electrons in the d-subshell are combined with Zn , Cd and Hg. The metallic bonds present in them are, therefore, weak. This is why they have low points of melting and bolting. therefore , this statement is true. These have maximum number of unpaired electrons. Since , these transition metals have all electrons paired , so this statement is incorrect.These have very strong metallic bonding -: Zn, Cd and Hg d-orbital are completely filled. They have poor metallic bonding and less compact packing due to their fully filled d-orbitals, so all of them are volatile in nature. Therefore, this statement is also not valid .These have more metal-metal bonding. -: Since , their metallic bond is weak , so this statement is not true .Hence , the correct option is A (These have all their electrons paired).
Answer question number 7
Answer:
C
Explanation:
It should be acidic soil that is below pH7. pH2-pH4 is too low and it is a strong acid. Plants won't survive in very high acidity soil
Can someone help me with number 4 please?
Consider the element sodium. It's atomic number is __________ and equals ___________.
Answer:
11 and equals the number of protons
Explanation:
colonel flanders makes boxes of chicken with various numbers of pieces. He charges $ 0.40 for each piece of chicken, plus a fixed charge of $ 0.55 for the box, the rolls, etc. If Iddy Ottic bought the $6.95 box, how many piecesof chicken should the box contain?
1. Write chemical reaction of burning of magnesium
2. Discuss about the reactivity of magnesium
3. Discuss the nature of magnesium oxide whether it is acidic or basic.
4. What will happen?. When magnesium oxide dissolved in water and tested by red litmus.
5. When Mg burns, which type of flame is obtained.
pls answer which u can
Answer:
1.Mg+O2.......MgO2
Explanation:
2.Very reactive towards halogens and reacts with water at room temperature. 3, Magnesium oxide is a simple basic oxide. 4.It will react with water to form magnesium hydroxide which is a base turning red litmus to blue 5.should be white. hope it helped. I help people although when I post a question it is left unanswered and then gets answers after two days when I don't really need it
Which refers to a method that relies on sound waves and is used by different animal species for navigation,
communication, and finding food?
echolocation
analog signaling
infrared detection
o digital location
HELP FAST ILL MARK BRAINLEST
Answer:
A
Explanation:
got it on edge
An echolocation refers to a method that relies on sound waves and is used by different animal species for navigation, communication, and finding food. Therefore, option A is correct.
What is an echolocation ?Echolocation is a method used by bats, dolphins, and other animals to locate objects using reflected sound. This enables the animals to move around in complete darkness, allowing them to navigate, hunt, recognize friends and enemies, and avoid obstacles.
(1) To hunt for prey, bats make high-frequency sounds. (2) Sound waves are used by dolphins and other toothed whales to locate prey and navigate their surroundings. (3) Nocturnal oil birds use echolocation to navigate their surroundings, particularly in low-light conditions.
Echolocation is used to help with orientation, obstacle avoidance, food acquisition, and social interactions.
Thus, option A is correct.
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what do you mean by work
Answer:
work is something u are working hard to get money or you are dedicated to it to have a daily wage
What is an ionic bond?
Answer:
Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion
Explanation:
pleaseee mark brainliest <3!
what is the standard form of 12,341 us?
Answer:
12341 in standard form = 1.2341 × 10⁴
Explanation:
When you split the number 12341 into a coefficient and a power of 10 you do get 12341 in exponential form, but there is an indefinite number of possibilities.
As you probably want 12341 in normalized scientific notation, the coefficient or significand of 12341 in scientific notation must be in the interval [1,10[.
As there are many ways to express 12341 in scientific notation, in this post we mean 12341 in normalized scientific notation, unless stated otherwise. Therefore:
12341 in scientific notation = 1.2341 × 10⁴.
This can also be expressed as 1.2341 × 10⁴, using the caret symbol, or as 1.2341e+4, which is called 12341 in e-notation.
How is burning magnesium different from burning methane?
Answer:
oxygen and magnesium come together in a chemical to form a reaction to it compound after it burns then it forms white powder of magnesium oxide but in the process magnesium gives up 2 electrons to oxygen atoms to form powdery product.
when you burn methane it crrates a blue flame in sufficient amounts of oxygen methane burns to give off carbon dioxide (Co2) and water (H2o)
Organizing information in a meaningful way is an example of what?
Answer:
Observation
Explanation:
In chemistry a chemist conducts an experiment and he/she concludes some points and arranges information about his/her experiment can be called observation or result
Organizing information in a meaningful way is an example of good management and the proper establishment of the research parameters.
In research, the correct organization of information is of the utmost importance.Information is the key to get proper results during research.That is why researchers must be very careful in the way they handle information.Proper sources should be taken into consideration to do research.The information obtained should be correctly organized and classified, according to the framework of research. This meaningful organization is key to the following interpretation of results.We conclude that organizing information in a meaningful way is an example of the proper control and follow-up process in research to interpret data and have valid conclusions.Learn more about this topic here:
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