Which scientist arranged the elements in order of increasing atomic number, rather than increasing atomic mass? Antoine Lavoisier Dmitri Mendeleev Henry Moseley John Newlands
The answer is: Henry Moseley.
Henry Gwyn Jeffreys Moseley (1887–1915) proposed that the number of positive nuclear charges (protons) in atom is equal to its atomic number in the periodic table.
Mendeleev did not know about isotopes and he arranged the elements in order of increasing relative atomic mass.
For example, positions of iodine and tellurium were reversed in Mendeleev's table, because of different isotopes, but Moseley solved anomalies like this one.
How does a volcano form?
Balance equation Al(s)+__CuSO4(aq) = ____Al2(SO4)3(aq)+____Cu(s)
Which of the following is an example of an Arrhenius base?
A. CaCO3
B. KOH
C. NH3
D. HCl
Answer: B. [tex]KOH[/tex]
Explanation:
According to the Arrhenius concept, an acid is a substance that ionizes in the water to give hydronium ion or hydrogen ion [tex](H^+)[/tex] and a bases is a substance that ionizes in the water to give hydroxide ion [tex](OH^-)[/tex].
According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates protons and a base is defined as a substance which accepts protons.
According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.
[tex]KOH\rightarrow K^++OH^-[/tex]: is a Arrhenius base.
[tex]NH_3+H^+\rightarrow NH_4^+[/tex] : is a lewis base as it donates the lone pair of electrons.
[tex]HCl\rightarrow H^++Cl^-[/tex] is a Arrhenius acid and bronsted lowry acid.
A player uses a hockey stick to push a puck at a constant velocity across the ice. The weight of the puck is 1.70 N. The coefficient of friction is 0.0600. With what force must the player push the puck so that his force just equals the frictional force?
Answer: The minimum force by which player should hit the puck to move it is 0.102 N.
Explanation:
Weight of the puck = 1.70 N
This weight of the puck is the force acting normal to the surface that is:
N = 1.70 N
The coefficient of friction =[tex]\mu _f=0.0600[/tex]
Frictional force = [tex]F_f=\mu _f\times N=0.0600\times 1.70 N=0.102 N[/tex]
The minimum force by which player should hit the puck to move it is 0.102 N.
For the reaction represented by the equation pb(no3)2 + 2ki → pbi2 + 2kno3, how many moles of lead(ii) iodide are produced from 300. g of potassium iodide and an excess of pb(no3)2?
a. 11.0 mol selected:
b. 1.81 mol
c. 3.61 mol
d. 0.904 mol
Number of moles equals of potassium iodide;
The molar mass of potassium iodide is 166 g/mole
Moles = 300/166
= 1.8072moles
According to the equation;
2 moles of KI produces 1 mole of PbI2 9lead (ii) iodide
Therefore; the number of moles of lead (ii) iodide produced will be;
= 1.8072/2
= 0.9036moles
Thus the number of moles of lead (ii) iodide is 0.904 mole
Answer : The correct option is, (d) 0.904 mole
Explanation : Given,
Mass of potassium iodide = 300 g
Atomic mass of potassium iodide = 166 g /mole
First we have to calculate the moles of potassium iodide.
[tex]\text{Moles of KI}=\frac{\text{Mass of KI}}{\text{Molar mass of KI}}=\frac{300g}{166g/mole}=1.807mole[/tex]
Now we have to calculate the moles of lead(ii) iodide.
The given balanced chemical reaction is,
[tex]Pb(NO_3)_2+2KI\rightarrow PbI_2+2KNO_3[/tex]
From the given balanced chemical reaction, we conclude that
As, 2 moles of potassium iodide react to give 1 mole of lead(ii) iodide
So, 1.807 moles of potassium iodide react to give [tex]\frac{1.807}{2}=0.904[/tex] mole of lead(ii) iodide
Therefore, the number of moles of lead(ii) iodide produced are, 0.904 mole
Snow melting in sunshine is an example of which type of change
What happens to the temperature of a thermometer near an endothermic reaction?
In part a, you found the amount of product (3.00 mol p2o5 ) formed from the given amount of phosphorus and excess oxygen. in part b, you found the amount of product (2.60 mol p2o5 ) formed from the given amount of oxygen and excess phosphorus.now, determine how many moles of p2o5 are produced from the given amounts of phosphorus and oxygen.express your answer to three significant figures and include the appropriate units.
Answer:
The correct answer is 2.60 moles.
Explanation:
The balanced equation is:
4P + 5O₂ ⇒ 2P₂O₅
The number of moles of O₂, n = mass/molar mass
208 g / 32 g/mol = 6.5 mol
From the balanced equation,
5 moles of O₂ reacts with 2 moles of P₂O₅
So, 6.5 moles of O₂ reacts with M moles of P₂O₅
M = 6.5 × 2/5
= 2.6 moles
Therefore, the required moles of P₂O₅ are 2.60 moles.
A chemist needs to prepare a solution of 1.7 m nacl. if 400. ml of the solution are required how many grams of nacl are needed? molar mass nacl = 58.5 g/mol
Describe how to separate a mixture of pigments from an ink cartridge.
#1: Which of the following scientists came up with the first widely recognized atomic theory?
A. John Dalton
B. Antione Lavoisier
C. Robert Millikan
D. J.J. Thomson
***My answer: A. John Dalton
is that right??,
Determine the number of moles of a gas which occupies 39.0mL at 27°C if the pressure is 107 kPa.
3.14 x 10-3 mol
5.52 x 10-3 mol
2.45 x 10-3 mol
1.67 x 10-3 mol
When it says Lithium crystallizes in a body centered cubic unit cell. what is the mass of one unit cell....
I did my math, but it says I have to multiply by 2. I am confused in why I have to do that?
I also have trouble understanding what is a body-centered cubic cell.
Magnesium sulfate heptahydrate is heated until all the water is driven off. The sample loses 11.80 grams upon heating. What was the mass of the original sample?
magnesium reacts with aluminum chloride. if you have 40g of each, how many grams of Al can you make? what is the LR? how much excess is left over after the reaction takes place
Which planet is not an outer planet? A. Mars B. Uranus C. Neptune D. Jupiter
Which metal atom below cannot form a cation of several different charges?
Why is it hard for scientists to change lead into gold?
Scientists would have to change the number of protons in lead atoms.
Scientists would have to change the number of electrons in lead atoms.
Scientists would have to change the number of neutrons in lead atoms.
Scientists would have to change the number of protons and neutrons in lead atoms.
Changing lead into gold requires changing the number of protons in the lead atoms, a process known as nuclear transmutation. This process is highly complex, energy intensive and has many potential risks, making it unfeasible as a method of gold production.
Explanation:The process of changing one element into another, such as changing lead into gold, would require the manipulation of its atomic structure. The atomic structure of an atom is primarily dictated by the number of protons it has, which determines its atomic number and essentially defines the kind of element it is. In the case of lead and gold, lead has 82 protons and gold has 79 protons.
To turn lead into gold, scientists would have to remove 3 protons from each atom, which is an incredibly difficult task. This process, known as nuclear transmutation, would require a significant amount of energy and highly advanced technology. Even then, the process is far from efficient and produces a number of problems including the release of harmful radiation and the production of unstable, radioactive isotopes.
Furthermore, changing the number of neutrons and electrons in a lead atom alone would not turn it into gold; the number of protons must be changed. So the correct statement from the options provided is that scientists would have to change the number of protons in lead atoms to transform it into gold. However, due to the immense difficulty and possible risks involved, this is not a viable option for gold production.
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Only 5 questions! All you have to do is check my answers...1. A flask contains four gases: CH4, O2, C2H5, and N2. When the stopper is removed, which gas will diffuse the fastest?
CH4 <---
O2
C2H5
N2
2. Which gas effuses 2.39 times slower than nitrogen gas?
O2
Cl2
Br2 <---
I2
3. What is the molecular mass of a gas that effuses three times faster than radon?
16 g/mol
25 g/mol <---
50 g/mol
67 g/mol,
Uranium is a metallic element that is used in nuclear reactors and nuclear weapons. the vast majority of uranium found on earth is in the form of uranium-238, an isotope with a mass number of 238, while the uranium that is used for nuclear reactors and weapons is uranium-235, an isotope with a mass number of 235. what is the atomic difference between uranium-235 and uranium-238? uranium-235 has three fewer protons than uranium-238. uranium-235 has three fewer neutrons than uranium-238. uranium-235 has three fewer electrons than uranium-238. uranium-235 has three fewer atoms than uranium-238.
Answer:
U-235 and U-238 are two radioactive isotopes of Uranium. The main difference between U-235 and U-238 is that the number of neutrons present in the U-235 nucleus is 143 whereas the number of protons present in the U-238 nucleus is 146.
Explanation:
Which is the correct symbol for the atom with 42 protons and 49 neutrons?
Explanation:
Number of protons present in an atom are actually the atomic number of atom. Each element will have different atomic number.
Hence, each element is different in nature. On the other hand, atomic mass is the sum of number of protons and number of neutrons present in an element.
For example, Molybdenum is the element with 42 protons and 49 neutrons. Molybdenum is represented by the symbol Mo.
Therefore, we can conclude that Mo is the correct symbol for the atom with 42 protons and 49 neutrons.
The correct symbol for the atom with 42 protons and 49 neutrons is ^91Mo.
Atomic notation explained.
The correct symbol for the atom with 42 protons and 49 neutrons is ^91Mo.
In atomic notation, the image for an component consists of the nuclear number (number of protons) as a subscript and the mass number (entirety of protons and neutrons) as a superscript.
For the given atom with 42 protons and 49 neutrons, the overall mass number is 42 + 49 = 91. Hence, the image for this particle is ^91Mo, speaking to the component Molybdenum (Moment) with a mass number of 91.
Learn more about atomic notation below.
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Which of the following accurately describes the behavior of water when subjected to temperature change?
A. A mass of water will expand if heated from 0°C to 2°C.
B. The volume of water will increase if cooled from 3°C to 2°C.
C. The volume of water will decrease if heated from 6°C to 7°C.
D. A mass of water will contract if cooled from 1°C to 0°C.
The answer option which accurately describes the behavior of water when subjected to temperature change is: B. The volume of water will increase if cooled from 3°C to 2°C.
Water refers to a liquid molecule that is typically made up of two (2) main chemical elements in the following proportion;
Two atoms of hydrogen.One atom of oxygen.Generally, the volume of water is directly proportional to its temperature.
Hence, an increase in the temperature of water causes the volume of water to increase because its molecules gain energy and move more rapidly, which in turn makes the water molecules to be further apart.
When water is cooled, it contracts (decrease in volume) until a temperature of approximately four degree Celsius (4°C) is reached and then it begins to expand (increase in volume) at lower temperatures (3°C to 2°C), until it reaches its freezing point, which is typically at zero degree Celsius (0°C).
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Why carbontetra chloride exist in liquid form at room temperature?,
If a base is added to water, what will occur?
Adding a base to water triggers a base ionization reaction, resulting in the formation of hydroxide ions and a conjugate acid, which increases the solution's pH. Strong bases fully dissociate, while weak bases only partially ionize.
Explanation:When a base is added to water, a base ionization reaction occurs. This reaction involves the transfer of protons from water molecules to the base molecules, producing hydroxide ions (OH-) and a conjugate acid of the base. For instance, if we take pyridine, C5NH5, as a base, adding it to water will result in the formation of hydroxide ions and pyridinium ions. This process increases the pH of the solution as it raises the concentration of hydroxide ions. Strong bases, like soluble ionic hydroxides (e.g., NaOH), dissociate completely in water, leading to a significant increase in OH- concentration, while weak bases yield a smaller proportion of hydroxide ions.
A general reaction for base ionization can be represented as B(aq) + H₂O(l) ⇒ HB*(aq) + OH⁻(aq), where B is the base and HB* is the conjugate acid formed. This reaction is essential for understanding acid-base chemistry, where bases are seen as proton acceptors and their strength can be gauged by how completely they ionize in water.
Connect It Imagine that you can see the particles of ice, liquid water, and water vapor. Describe how these three states of water differ.
#1: Which of the following is a brittle solid?
A. chlorine
B. bromine
C. iodine
D. sulfur
**my answer; C. iodine
is that right?,
If a solution containing 51.429 g of mercury(ii) perchlorate is allowed to react completely with a solution containing 16.642 g of sodium sulfate, how many grams of solid precipitate will be formed?
At room temperature, the surface tension of water is 72.0 mJ·m–2. What is the energy required to change a spherical drop of water with a diameter of 1.20 mm to five smaller spherical drops of equal size? The surface area of a sphere of radius r is 4π r2 and the volume is 4π r3/3.
2H2S + 3O2 mc008-1.jpg 2SO2 + 2H2O Which option gives the correct mole ratios?
is the aswer H2S:SO2=2:2 and O2:H2O=3:2