Answer:
Antoine Lavoisier and Johann Wolfang Döbereiner organized the elements based on properties such as how the elements reacts or whether they are solid or liquid.
Explanation:
The periodic table of the elements as we have it today was developed as a result of the work of several notable centuries who lived centuries apart, all of who made notable contributions to development of the modern periodic table in use today.
In 1789, Antoine Lavoisier, a French Chemist provided a definition of elemets which he defined as a substance whose smallest units cannot be broken down into a simpler substance. He further grouped the elements into two as metals and nonmetals.
In 1829, German physicist Johann Wolfang Döbereiner arranged elements in groups of three in increasing order of atomic weight and called them triads. His arrangement owasf elements into triads was based on his observation of similarities in physical and chemical properties of certain elements.
John Newlands, a British Chemist was the first to arrange the elements into a periodic table with increasing order of atomic masses.
In 1869, Russian chemist Dmitri Mendeleev developed a periodic table which provided a framework the modern periodic table. He arranged the elements according to their atomic weight, leaving gaps for elements that were yet to be discovered.
The modern periodic table arranges elements based on increasing atomic number.
What force is important in the creation of both coal and petroleum?
Explanation:
heat and pressure are two main forces that transform organic matter into fossil fuels
what is indepent and dependent variables
Answer:
The independent variable is the cause. Its value is independent of other variables in your study.
The dependent variable is the effect. Its value depends on changes in the independent variable.
Ex: The ice cube melts on the stove.
Dependent variable: Ice Cube
Independent variable: heat of stove
Answer:
In an experiment, the IV(independent variable) is a variable that is changed to see how it affects something else, and the DV (dependent variable)is a variable that is being measured/observed.
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can someone check if i did this right. thank you !!
Answer:
noo
Explanation:
its basic
....................
Answer: acidic
Explanation:
. Calculate the pH and the pOH of each of the following solutions at 25 °C for which the substances ionize completely:
(a) 0.200 M HCl
(b) 0.0143 M NaOH
(c) 3.0 M HNO3
(d) 0.0031 M Ca(OH)2
Based on the molarity of the solutions;
For 0.200 M HCl; pH = 0.699, pOH = 13.301For 0.0143 M NaOH; pOH = 1.845, pH = 12.16For 3.0 M HNO3; pH = -0.4771, poH = 14.4771For 0.0031 M Ca(OH)2; pOH = 2.21, pH = 11.79What pHand pOH?pH is the negative logarithm to base ten of the hydrogen ions concentration of a solution.
pH = -log[H+]pOH is the negative logarithm to base ten of the hydroxide ions concentration.
pOH = -log[OH-]Also;
pH + pOH = 14For HCl:
pH = -log [H3O+]
pH =-log (0.200)
pH = 0.699
Then;
poH= 14-0.699
pOH = 13.301
For NaOH:
pOH= -log [OH-]
= -log (0.0143)
pOH = 1.845
Then;
pH= 14-poH
= 14- 1.845
pH = 12.16
For HNO3:
pH= -log[H3O+]
=-log(3.0)
= -0.4771
Then;
pOH = 14-9-0.4771
pOH = 14.4771
For [Ca(OH)2]
molarity = 0.0031M
2 moles of OH- are produced
[OH-]= 2 × 0.0031
[OH-] = 0.0062M
pOH = - log[OH-]
=-log(0.0062)
=-log(6.2x10-3)
=-(-2.21)
pOH = 2.21
Then;
pH =14-2.21
pH =11.79
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Who is my favourite wrestler?
Answer:
ma herdina thesto wrestling
The table below shows two types of electromagnetic waves and three random applications of electromagnetic waves.
Type of Wave Applications of Waves
Gamma rays 1. Used in spectrometers to measure elements on the surface of celestial bodies
Radio waves 2. Used to measure gravity fields
3. Detect the heat released by astronomical objects
Which of these best matches the waves with their applications?
Gamma rays—2 and radio waves—3
Gamma rays—3 and radio waves—2
Gamma rays—2 and radio waves—1
Gamma rays—1 and radio waves—2
Answer:
Gamma rays—3 and radio waves—2
Explanation:
hard time seeing question, but i believe it is Gamma rays—3 and radio waves—2
The reaction below is performed with 10.0 g of Al and 19.0 g of O2. How many grams of aluminum oxide will be made? 4 Al (s) + 3 O2 (g) → 2 Al2O3 (s)
Answer:
18.89 g of Al₂O₃.
Explanation:
The balanced equation for the reaction is given below:
4Al + 3O₂ —> 2Al₂O₃
Next, we shall determine the masses of Al and O₂ that reacted and the mass of Al₂O₃ produced from the balanced equation. This can be obtained as follow:
Molar mass of Al = 27 g/mol
Mass of Al from the balanced equation = 4 × 27 = 108 g
Molar mass of O₂ = 16 × 2 = 32 g/mol
Mass of O₂ from the balanced = 3 × 32
= 96 g
Molar mass of Al₂O₃ = (27×2) + (16×3)
= 54 + 48
= 102 g/mol
Mass of Al₂O₃ from the balanced equation = 2 × 102 = 204 g
SUMMARY:
From the balanced equation above,
108 g of Al reacted with 96 g of O₂ to produce 204 g of Al₂O₃.
Next, we shall determine the limiting reactant. This can be obtained as follow:
From the balanced equation above,
108 g of Al reacted with 96 g of O₂.
Therefore, 10 g of Al will react with
= (10 × 96)/108 = 8.89 g of O₂.
From the calculation made above, we can see clearly that only 8.89 g out of 19 g of O₂ given, reacted completely with 10 g of Al.
Therefore, Al is the limiting reactant and O₂ is the excess reactant.
Finally, we shall determine the mass of aluminium oxide, Al₂O₃, produced from the reaction.
NOTE: in this case, the limiting reactant will be used because it will give the maximum mass of the aluminium oxide, Al₂O₃ as all of it is consumed in the reaction.
Al is the limiting reactant and the mass of aluminium oxide, Al₂O₃ produced can be obtained as follow:
From the balanced equation above,
108 g of Al reacted to produce 204 g of Al₂O₃.
Therefore, 10 g of Al will react to produce = (10 × 204)/108 = 18.89 g of Al₂O₃.
Thus, 18.89 g of Al₂O₃ were obtained from the reaction.
Which of the following is an advantage of using an energy-efficient household
appliance instead of a traditional household appliance?
A. It works only during the daytime.
B. It uses no electricity
c. It conserves electricity.
D. It does not work as effectively
do the
math!
Wavelength Frequency
Speed
Medium
200 Hz
1500 m/s
The table shows measurements of
some properties of a sound wave in
water and in air.
Water
400 Hz
3.75 m
Water
343 m/s
Air (20°C)
10 m
Calculate Using what you know
about the relationship between
wavelength, frequency, and speed,
fill in the table.
17.15 Hz
343 m/s
Air (20°C)
1a
CHALLENGE What can this table
tell
you about the speed of a wave?
Answer:
everything can be found in the picture
What volume of water is needed to make up a 6.00% (m/v) solution of copper (II) sulphate when 12.0 g of it will be added to water?
Answer:
200 mL of water is needed to make up a 6.00% (m/v) solution of copper (II) sulphate when 12.0 g of it will be added to water.
Explanation:
The solution is the result of the mixture between the solute, which is the substance that dissolves, and the solvent, which is the substance in which a solute dissolves. That is, a solution (or solution) is a mixture of two or more components, perfectly homogeneous since each component is intimately mixed with the other.
The concentration of solutions is the amount of solute contained in a given amount of solvent or solution. A unit of concentration is the percent weight to volume.
The percent weight to volume is the percentage ratio between the weight of the solute and the volume of the solution. It is calculated as:
[tex]Percent =\frac{mass of solute}{volume of solution} *100[/tex]
Mass is measured in grams, while volume is measured in mL.
In this case:
Percent weight to volume= 6%mass of solute= 12 gvolue of solution= ?Replacing:
[tex]6=\frac{12 g}{volume of solution} *100[/tex]
Solving:
volume of solution*6= 12 g*100
[tex]volume of solution=\frac{12 g}{6} *100[/tex]
volume of solution= 200 mL
200 mL of water is needed to make up a 6.00% (m/v) solution of copper (II) sulphate when 12.0 g of it will be added to water
URGENT!!!
A solution has a [H3O+] of 1 × 10−5 M. What is the [OH−] of the solution? (5 points)
9 M
14 M
1 × 10−9 M
1 × 10−14 M
Answer:
[tex]{ \bf{from \: ionic \: product \: of \: water : }} \\ { \boxed{ \tt{k _{w} = [H _{3} O {}^{ + } ][OH {}^{ - } ]}}} \\ \\ { \tt{1 \times {10}^{ - 14} = (1 \times {10}^{ - 5} ) [OH {}^{ - } ]}} \\ \\ { \tt{[OH {}^{ - } ] = 1 \times {10}^{ - 9} }} \: M[/tex]
A solution has an [H3O+] of 1 × 10−5 M the [OH−] of the solution will be 1 × 10−9 M and option C is correct.
What is [OH−] of the solution?The water is made up of H2O only and when the pH of it is 7 then the concentration of all the ions would be the same while dissociation the water will get dissociate into H+ ions and OH- ions.
The concentration of OH- ions will be
OH- = Kw {H3O+}
{H3O+} = 1 × 10−5 M.
Kw = 14
substituting the value in the equation,
OH = 14 { 1 × 10−5 M.}
OH = 1 × 10−9 M
Therefore, the solution has an [H3O+] of 1 × 10−5 M the [OH−] of the solution will be 1 × 10−9 M and option C is correct.
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An element X has the proton number 18.
The next element in the periodic table is an element Y.
Which statement is correct?
Answer:
This question is incomplete
Explanation:
This question is incomplete. However, the element X with the atomic number of 18 is Argon (Ar) while the next element (element Y) in the periodic table, with atomic number 19, is potassium (K).
Element X is found in the group zero (also called group 18 and elements found therewith are referred to as noble gases) of the periodic table while element Y is found in group 1 (elements found here are referred to as alkali metals).
Element X has a completely filled outermost shell while element Y has one electron in its outermost shell.
Element X is a metal while element Y is a nonmetal.
Consider the following chemical reaction:
HF + NaOH - NaF + H20
Energy must be invested in order for the reaction to proceed.
What bonds must be broken in order for the reaction to proceed.
Select ALL that apply.
A. An ionic bond between sodium and hydroxide.
B. An ionic bond between sodium and fluorine.
C. A covalent bond between sodiume and fluorine.
D. An ionic bond between hydrogen and fluorine.
DE. A covalent bond between hydrogen and fluorine.
DE A covalent bond between hydrogen and oxygen
Answer: The correct options are A and E
Explanation:
A chemical reaction is defined as the reaction in which two or more chemical substances react to form two or more different chemical substances.
A new substance (product) is formed in a chemical reaction when the bonds between the reactants are broken so that the new bonds between the products can be formed.
For a given chemical reaction:
[tex]HF+NaOH\rightarrow NaF+H_2O[/tex]
Here,
HF is a covalent compound as sharing of electrons take place between hydrogen and fluorine atom
NaOH is an ionic compound as a complete transfer of electrons occurs from sodium to hydroxide.
Thus, to form the products, an ionic bond between sodium and hydroxide must be broken coupled with a covalent bond between hydrogen and fluorine.
Hence, the correct options are A and E
Determine the number of protons, electrons, and neutrons present in an atom of patassium. Explain how you determined your answer using complete sentences.
Please make sure your right.
Thank you!!!
The electrolysis of water has the equation 2H2O (l) → 2H2 (g) + O2 (g). What type of reaction is this?
A)
Single displacement
B)
Double displacement
C)
Decomposition
D)
Synthesis
Answer:b
Explanation:
what is periodic law
What dose the wave carry
Answer:
Waves carry energy from one place to another.
Because waves carry energy,some waves are used for communication,eg radio and television waves and mobile telephone signals.
Explanation:
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that's my answer
correct me if im wrong
#carryonlearningWhich of the following is an example of nuclear fission?
A. A gamma emitter is used to trace movement of chemicals in the
environment.
B. A radioactive drug that emits electrons is used to treat cancer in a
patient.
O c. Two different isotopes of hydrogen form an isotope of helium on
the sun.
O D. A large radioactive atom breaks into smaller atoms, producing
nuclear energy.
The statement which is an example of nuclear fission is that a large radioactive atom breaks into smaller atoms, producing nuclear energy.
What is nuclear fission?Nuclear fission is a kind of radioactive decay reaction in which an unstable nuclei of an atom will split into smaller stable nuclei by the emission of lots of energy.
Gamma emitter is used inside the human body to trace the information that assists in making a diagnosis by the help of medication.To treat cancer patient high energetic rays like x-rays, gamma-rays are used.Formation of isotope of helium from two different isotopes of hydrogen is an example of nuclear fussion reaction.Hence in nuclear fission a large radioactive atom breaks into smaller atoms, producing nuclear energy.
To know more about nuclear fission, visit the below link:
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Concentrations-
How many moles of HCI are present in 562.0 ml of a 6.17 M HCI solution?
If possible, show work.
type of intermolecular forces in paraffin
Answer:
The intermolecular forces between paraffin molecules are entirely due to dispersion forces, and are therefore size dependent.
Explanation:
Answer: The intermolecular forces between paraffin molecules are entirely due to dispersion forces, and are therefore size dependent.
Explanation:
The intermolecular forces between paraffin molecules are entirely due to dispersion forces, and are therefore size dependent. 103 Paraffin wax is soluble in: a) water; b) hexane; c) acetone; d) ethanol Is shopping bag (polyethylene)
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In the diagram shown, what is occurring at the section marked 4 ?
Temperature
:: ا
4
2
Heat Energy
O Melting
Freezing
O Condensation
O Vaporization
Answer:
Vaporization
Since the question does not specify what molecule is being acted upon by the increment in temperature, I'll assume it's water.
When first taken out of the fridge, water is in the form of ice, and it has not been affected by a change in temperature yet, so it's at the origin.
(origin = ice)
As you raise the temperature, however, the ice starts to melt, and melting occur during phase 2. You have to keep the temperature constant for the process to properly occur.
(phase 2 = melting)
After it finishes melting, the ice is now in it's liquid state, which is water. The temperature continues to rise in order to proceed to the next phase.
(2nd slope = water)
Lastly, Water is being vaporized during phase 4. Notice, the temperature is kept constant in order to allow the process to properly occur.
(phase 4 = vaporization)
12. Which nonmetal is the most reactive?
A bromine
B
iodine
C) fluorine
D) chlorine
Answer:
C Fluorine
Explanation:
How did reducing the number of
decomposers affect the amount of carbon
dioxide in the ecosystem?
Answer:
As organisms release energy during cellular respiration, carbon dioxide is produced from the carbon in energy storage molecules. ... Carbon dioxide in the biodome decreased because decomposers decreased which means there was a decrease in cellular respiration overall.
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REACTION TYPE:
Single displacement/Oxidation-reduction
(Hope this helped UwU)
Answer:
Synthesis reaction is the answer
Pleaseee helpppp.....
Answer:
C. All of the above
Explanation:
They all happen beyond critical point.
the structure of butanoic acid
answer on here fjchcjfjdnc.com
why does shampoo remove hair grese for chemistry acids and alkali
Determine the number of subatomic particles in bromine-35.
Number of subatomic particles=35+36+35=106
Explanation:
Atomic number=35
Mass number=71
No. of proton p=35
No. of neutron n=71−35=36
No. of electron e=35
Identify the atom oxidized, the atom reduced, the oxidizing agent, and the reducing agent. 2Fe + 3V2O3 -------> Fe2O3 + 6VO
Explanation:
Fe- reducing agent (since it is oxidized to fe203)
v203- oxidizing agent(since it is reduced)
In the given reaction, Fe is the reducing agent and V is the oxidizing agent.
What is a reducing agent?An atom or compound that loses its electrons to other substances in a reduction-oxidation reaction and gets oxidized to a higher valency state is called a reducing agent.
A reducing agent can be defined as one of the reactants of a redox reaction that reduces the other reactant by giving its electrons to the reactant. If the reducing agent can not give away its electrons to others in a reaction, then the reduction reaction cannot occur.
Given, the following chemical reaction:
2Fe + 3V₂O₃ → Fe₂O₃ + 6VO
The V₂O₃ oxidation state of V:
2 x + 3(-2) = 0
2x = 6
x = + 3
The Fe₂O₃ oxidation state of Fe:
2 y + 3 (-2) = 0
2y = 6
y = + 3
The V acts as an oxidizing agent because it accepts one electron to change the oxidation state from +3 to +2.
Fe acts as a reducing agent because it gives out its electrons to change the oxidation state from 0 to +3.
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What is the molecular geometry of Br2
