Answer:
in order of their atomic mass
The first periodic table created by Mendeleev was based on the atomic masses of elements. Later Mosely modified it based on the atomic number.
What is periodic table ?Periodic table is the classification of all the known elements based on their atomic number. There are 118 elements in periodic table now. They are classified into different groups and periods.
Mendeleev was first to create periodic table for the easy classification of elements. He classified elements based on their atomic masses. At that time there were only 60-65 elements discovered.
Later Mosley modified it to modern periodic table based on the increasing order of atomic number of elements. Therefore, the first arrangement was based on atomic masses.
Find more on periodic table :
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Why does every chemical reaction require a certain amount of activation energy?
Explanation:
Activation energy is the minimum amount of energy required for a chemical reaction to take place.
When a chemical reaction occurs then bonds between the reactants break and bonds between the products are formed. This leads to the formation of an activated complex which is also known as transition state.
So, in order to form the activated complex a minimum amount of energy is necessary and this energy is known as activation energy.
For a reaction, AH = 176 kJ/mol and A SO = 0.285 kJ/(K•mol). At what
temperatures is this reaction spontaneous?
A. At no temperature
B. T< 50 K
C. T> 617 K
D. T< 617K
What do we need in order to obtain energy?
Explanation:
hope it helps thanks ❤
brainliest please
Answer:
Explanation:
human obtains energy by eating food. as food is digested n broken down in our digestive system, energy is released to our body.
what would happen if you boil a substance in an alcohol
Answer:
When a mixture of water and alcohol boils, the vapors are a mixture of water vapor and alcohol vapor
Boiling the solution causes the equilibrium in the following reaction to shift to the ________. HCO3- H3O --> H2CO3 H2O
Answer:
Right
Explanation:
The reaction of bicarbonate ion with acid is shown in the following equation;
HCO3- + H3O --> H2CO3 + H2O
This reaction is endothermic. This implies that energy must be absorbed from the surrounding as the reaction progresses.
Hence, when the solution is boiled, energy is supplied to the system in the form of heat and the forward reaction is favoured hence the equilibrium shifts to the right.
ayuda, ayuda, ayuda urgente tengo 5 minutos necesito el nombre de lo que viene en las imágenes
Answer:huh
Explanation:
what is the wave speed
a wave with a wave length of 1000 m and a frequancy of 3000000 Hz
Answer:
v = 3,000,000,000 m/s
Explanation:
v = f *L
v = 3,000,000 * 1000
v = 3,000,000,000 m/s
Q2.
This question is about metals and metal compounds.
(a)
Copper oxide reacts with hydrochloric acid to produce copper chloride and water.
Copper oxide is insoluble in water.
Copper oxide is gradually added to hydrochloric acid until in excess.
Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen.
Plan an investigation to find the accurate volume of hydrogen produced from
magnesium
You do not need to write about safety precautions.
Answer:
sry I don't know the answer
In an electrically neutral atom, the number of
protons equals the number of neutrons.
protons equals the number of electrons.
neutrons equals the number of electrons.
A. Protons equals the number of neutrons
B. Protons equal the number of electrons
C. Neutrons equals the number of electrons
Answer: B
Answer:
B
Explanation:
because protons have a +1 charge and electrons have a -1 charge, so if an atom is neutral it must have the same amount of protons and neutrons
How many molecular of H2O and O2 are present in 8.5g of H2O2 ?
2H2O+O2--->2H2O2
8.5 gm H2O2=0.25 mole
hence H2O is also 0.25 mole i.e.4.5 gm
O2is 0.125 mole i.e.4 gm
what is 10x412x3021x13123
The molar mass of oxygen(O) is 32g. What is the mass of 1.05*10^25 molecules of O²
Answer:
Hope that will help you
Explanation:
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Stoichiometry - Chemistry
Answer:
C
Explanation:
in the option C when we rearrange it then it will he C3H6O2
Answer:
yes its C
Explanation:
correct me if iam wrong
When a gas is heated,
Answer: when gas is heated ,they gain more kinetic energy causing them to move faster.
Explanation: so as they gain kinetic energy they hit the walls of the container with more force thus causing pressure to increase
HOPE THIS HELPSS comment if u need more explanation
A solution of known concentration is called
Answer:
It is called standard solution.
Explanation:
I hope this helps! Have a nice dayy! :)
You react 25.0 grams of aluminum with iron (II) chloride. How many grams of iron will you
make? 2A1 + 3FeCl2 --> 2AlCl3 + 3Fe
(PLS HELP ASAP)
Explanation:
hope the picture above helps you to understand:)
Balance equation for. _Mg + _H3(PO4) --_Mg3(PO4)2+ _H2
The reaction from NaOH and CH3COOH gives
a. Basic Salt
b. Acidic Salt
c. Normal Salt
d. Neutral Salt
If an atom has 32 protons in the nucleus, how many electrons will it have orbiting the nucleus
An atom is neutral as it has the same number of electrons that of protons. So, if an atom has 32 protons i.e. the atomic number of it is 32, then it will have 32 electrons revolving the nucleus.
7. Explain the difference between an ionic compound and a molecule, on an atomic
level (that is, describe what is happening with the atoms that makes these compounds
different)
Answer:
bakit Kay's lahat Ng module mahirap
what kind of food preserve for curing
Answer:
bitter leaf soups
Explanation:
because it cures gems out our body system
If an equilibrium system contains gaseous reactants and/or products, a change in volume will cause a change in concentration and pressure. A decrease in volume will cause the system to shift in the direction that produces _____ moles of gas in total, whereas an increase in volume causes a shift in the direction that produces _____ moles of gas in total.
Answer:
Less
More
Explanation:
When a constraint is imposed on a reaction system in equilibrium, the equilibrium position will shift in such a way as to annul the constraint.
When the volume of a reaction system in equilibrium is decreased, the equilibrium position will shift in the direction having less total number of moles.
Similarly, when the volume is increased, the equilibrium position shifts to the direction having a greater total number of moles.
Which of the following equalities is not correct?
a. 1 cm^3 = 1 mL
b. 1000 mm = 1 m
c. 100 cg = 1 g
d. 10 kg = 1 g
Answer:
a. 1 cm^3 = 1 mL
explanation:
10:38 Fri 9 Jul
ES
GCSE Science - Chemistry
2 of 15
Name the indicator that is red in acid and turns green when the solution becomes neutral.
|
Answer.
Universal indicator
Explanation.
Universal indicator has many different colour changes, from red for strongly acidic solutions to dark purple for strongly alkaline solutions. In the middle, neutral pH 7 is indicated by green.
What is the symbol for an ion with a 3+ charge, 28 electrons, and a mass number of 71
Answer:
Ga3+ is a gallium cation
HELP ASAP!! PLZ
What information is needed to determine a molecular formula?
A. The empirical formula and the molarity of the solution
B. The empirical formula and the empirical formula mass
C. The empirical formula and the percent composition
ОО
D. The empirical formula and the molar mass
SUBMIT
D. The empirical formula and the molar mass
Which option best describes the water cycle?
Determine the enthalpy for the reaction A+B --> C If we know the following:
A+E --> C+D; delta H = -200 kJ
D+B --> E; delta H = -100 kJ
Explanation:
here is the answer to the question
True or false The atomic number of an element is always more than the mass number of that element.
In an atomic model that includes a nucleus, positive charge is
a
concentrated at multiple sites in an atom.
b
concentrated in the center of an atom.
c
spread evenly throughout an atom.
d
located in the space outside the nucleus.
