Answer:
Hellium (He): 1s2
Nitrogen (N): 1s2 2s2 2p6
Silicon (Si): 1s2 2s2 2p6 3s2 3p2
The orbital configuration of following elements is as follows:i) helium- 1 s² ii)nitrogen- 1 s² 2 s² 2 p³ iii)silicon-1 s² 2 s² 2 p⁶ 3 s² 3 p²
What are elements?It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.
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If the mercury in a manometer raises 30.0 millimeters due to a change in pressure, what is the corresponding change in pressure in atm?
Answer:
0.03947 atm
Explanation:
The relationship between mmHg and atm is given as;
1 atm = 760 mmHg
x atm = 30 mmHg
Upon solving for x;
x * 760 = 30 * 1
x = 30 / 760 = 0.03947 atm
If a solution containing 24.0 g of a substance reacts by first-order kinetics, how many grams remain after three half-lives?
Answer:
3.0g remain
Explanation:
The half-life is defined as the time required for a reactant to decrease its concentration in exactly the half of the initial amount of reactant. Having this in mind:
In one half-life, the mass will be:
24.0g / 2 = 12.0g
In two half-lifes:
12.0g / 2 = 6.0g
And in three half-lifes, the mass that remain is:
6.0g / 2 =
3.0g remainRocks are classified on the basis of
Answer:
Rocks are classified according to characteristics such as mineral and chemical composition, permeability, texture of the constituent particles, and particle size. This transformation produces three general classes of rock: igneous, sedimentary and metamorphic. Those three classes are subdivided into many groups.
Explanation:
How many moles are there in 2.30 x 1024 atoms of silver?
Answer:
Step 1 should be convert atoms to moles (n). Step 2 should be convert moles (n) to mass (m).
Step 1
Use dimensional analysis to convert the number of atoms to moles.
1 mole atoms = 6.022 × 10²³ atoms
n(Ag) = 2.3 × 10²⁴ Ag atoms × (1 mol Ag/6.022 × 10²³ Ag atoms) = 3.8193 mol Ag
Step 2
Convert the moles of Ag to mass.
mass (m) = moles (n) × molar mass (M)
n(Ag) = 3.8193 mol Ag
M(Ag) = atomic weight on the periodic table in g/mol = 107.868 g Ag/mol Ag
m(Ag) = 3.8193 mol × 107.868 g/mol = 412 g Ag = 410 g Ag rounded to two significant figures
The mass of 2.3 × 10²⁴ Ag atoms is approximately 410 g.
Explanation:
The number of moles that are present is 2.3 × 10²⁴ atoms of silver are 3.8193 moles that can be determined using Avogadro's law.
The calculation for number of moles:One mole:
A mole is defined as 6.022 × 10²³ of some chemical unit, be it atoms, molecules, ions, or others.
1 mole = 6.022 × 10²³ atoms
n(Ag) = 2.3 × 10²⁴ Ag atoms × (1 mol Ag/6.022 × 10²³ Ag atoms)
n(Ag) = 3.8193 mol Ag
Thus, the number of moles is 3.8193 moles.
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Molten zinc chloride can be electrolysed.
Describe how this experiment can be carried out in a laboratory, explaining how the products of this electrolysis are formed.
(6) marks
Answer: The products of electrolysis are Zn(l) and [tex]Cl_2[/tex] gas
Explanation:
Electrolysis of a subastance is breaking it into its constituents by the action of electrical current.
In the electrolysis of molten zinc chloride, zinc metal is produced at the cathode which is a negative electrode and chlorine gas produces as the anode which is a positive electrode.
[tex]ZnCl_2(l)\rightarrow Zn^{2+}+2Cl^-[/tex]
At anode : [tex]2Cl^-(l)\rightarrow 2e^-+Cl_2(g)[/tex]
At cathode : [tex]Zn^{2+}(l)+2e^-\rightarrow Zn(l)[/tex]
3. Which state of matter has a defined shape?
HELP FAST
Answer:
Solid state of matter has a definite shapeThe answer to this is solids!
Iron-59 which is used to diagnose anaemia has a half life of 45days, what fraction of it is left in 90 days
Answer:
0.25 of the original
Explanation:
(0.5)^(90/45)
The fraction of iron-59 after 90 days is 0.25.
Iron-59 decays following first-order kinetics. Given the half-life ([tex]t_{1/2}[/tex]) of 45 days, we can calculate the rate constant (k) using the following expression.
[tex]k = \frac{ln2}{t_{1/2}} =\frac{ln2}{45day} = 0.015 d^{-1}[/tex]
For first-order kinetics, we can find the fraction of Fe ([Fe]/[Fe]₀) after and an elapsed time (t) of 90 days, using the following equation.
[tex]\frac{[Fe]}{[Fe]_0} =e^{-k \times t } = e^{-0.015 d^{-1} \times 90 d } \approx 0,25[/tex]
The fraction of iron-59 after 90 days is 0.25.
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Jane is sitting in the family car. Her mother is driving her from their house to the library. Jane waves as she passes her friend Marina. Which of the following is not moving with respect to Jane?
A. Marina
B. The family car
C.The library
D. Jane’s house
Answer:
B) The family car
Explanation:
I hope this helps :)
A 0.90 g of hydrogen chloride (HCl) is dissolved in water to make 5.0 L of solution. What is the pH of the resulting hydrochloric acid solution?
Express the pH numerically to two decimal places.
0.50g of sodium hydroxide (NaOH) pellets are dissolved in water to make 4.0L of solution. What is the pH of this solution?
Express the pH numerically to two decimal places.
Answer:
Explanation:
Mol weight of HCl = 36.5
.90 g of HCl = .90 / 36.5 mole = .02465 mole
HCl = H⁺ + Cl⁻
1 mole 1 mole
1 mole of HCl gives 1 mole of H⁺
.02465 mole of HCl will give .02465 mole of H⁺
.02465 mole of H⁺ in 5 litre soln
concentration of H⁺ = .02465 / 5 = 4.93 x 10⁻³ M
pH = - log ( 4.93 x 10⁻³ )
= 3 - log 4.93
= 3 - .693
= 2.307
= 2.31
NaOH :
Mol weight of NaOH = 40
.50 g of HCl = .50 / 40 mole = .0125 mole
NaOH = Na⁺ + OH⁻
1 mole 1 mole
1 mole of NaOH gives 1 mole of OH⁻
.0125 mole of NaOH will give .0125 mole of OH⁻
.0125 mole of OH⁻ in 4 litre soln
concentration of OH⁻ = .0125 / 4 = 3.125 x 10⁻³ M
pOH = - log ( 3.125 x 10⁻³ )
= 3 - log 3.125
= 3 - .495
= 2.505
pH = 14 - pOH
= 14 - 2.505
= 11.495 .
= 11.50
For most substances the density of a solid form is slightly greater than the density of liquid form water however is different it is slightly less dense in the solid form than it is in liquid form compare water in the solid form with neon argon in oxygen and proposal reason why solid water is less dense liquid water
Answer:
Answer: When water freezes, water molecules form a crystalline structure maintained by hydrogen bonding. Solid water, or ice, is less dense than liquid water. Ice is less dense than water because the orientation of hydrogen bonds causes molecules to push farther apart, which lowers the density.
Explanation:
What is the surface composition of planets in the solar system?
A,. Helium or hydrogen
B,. Rock or gas
C., Rock or water
D,. Water or helium
Answer:
A: Helium or Hydrogen
Explanation:
Terrestrial planets are the 4 inner most planets of the solar system which are mercury, venus, earth, Mars, while the giant planets are the 4 outer most which are Jupiter, Saturn, Uranus and Neptune.
Now, these outer most ones are the surface ones and are surrounded primarily by layers of hydrogen and helium gases.
Help! I’ll give brainliest if u get it right!
Answer:
That is the Atomic mass
Explanation:
The element symbol is S, Element name is sulfur, and
Atomic number is 16
5. Why is picric acid and tannic acid used in the treatment of burns?
What is it called when instead of getting rid of a product you find another
use for the product?
Answer:
Recycling.
Explanation:
When instead of getting rid of a product you find another use for the product, it is called recycling.
Recycling can be defined as a process which typically involves gathering, processing and transformation of materials or products that would otherwise be gotten rid of as waste materials or trash into new products that could be used for another purpose.
Basically, the recycling process involves turning a trash or unwanted product into a treasure (new product) that is capable of serving another purpose.
For example, the crown cork of a bottle could be gathered and processed into art forms that can be used for decorations.
Question 2 2 points)
Which of the atoms shown has an atomic number of 42
1
2
4
7
Answer:
4 is the answer
Explanation:
i am not sure for this question
. Which state of matter has a defined volume but no defined shape?
HELPPPP PLEASE FAST
Answer:
liquid
Explanation:
it's not plasma, solid, or gas
so I think liquid
Which food dyes in the diagram on the right only contain one colour?
( Science, Chromatography )
What type of reaction
the following chemical reaction?
2C2H4O2 → C4H6O3 + H2O
Both magnetic fields and electric fields can exert a force true or false?
Answer:
false
Explanation:
An electric field may do work on a charged particle, while a magnetic field does no work.
When drawing a Bohr model for Sulfur, how many energy levels will you
draw?
5
4
3
2.
Answer:
3
Explanation:
2,8,6
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that 92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
Answer:
the change in energy of the gas mixture during the reaction is 227Kj
Explanation:
THIS IS THE COMPLETE QUESTION BELOW
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
From thermodynamics
ΔE= q + w
Where w= workdone on the system or by the system
q= heat added or remove
ΔE= change in the internal energy
q=+ 319kJ ( absorbed heat is + ve
w= -92kJ
If we substitute the given values,
ΔE= 319 + (-92)= 227 Kj
With the increase in enthalpy and there is absorbed heat, hence the reaction is an endothermic reaction.
Excess silver(I) nitrate was added to a 8.500 g mixture containing some amount of barium chloride, and 7.123 g of silver chloride was obtained. The unbalanced equation is
AgNO3 + BaCl2(aq) --> Ba(NO3)2(aq) + AgCl(s).
What is the mass% of BaCl2 in the mixture?
Answer:
60.88%
Explanation:
The balanced equation of the reaction is given as;
2 AgNO3 (aq) + BaCl2 (aq) → 2 AgCl (s) + Ba(NO3)2 (aq)
Since AgNO3 is in excess, the limiting reactant is BaCl2. From the reaction;
1 mol of BaCl2 produces 2 mol of AgCl
Converting to masses;
Mass = Number of mol * Molar mass
BaCl2;
Mass = 1 * 208.23 g/mol = 208.23 g
AgCl;
Mass = 2 * 143.32 g/mol = 286.64 g
208.23 g BaCl2 produces 286.64 g of AgCl
x g BaCl2 produces 7.123 g of AgCl
Solving for x;
x = 7.123 * 208.23 / 286.64 = 5.1745 g
Mass percent = Mass / Total mass of Mixture * 100
Mass Percent = 5.1745 / 8.500 = 0.6088 * 100 = 60.88%
At room temperature, CsF is expected to be:______.
a. a soft solid.
b. a conducting solid.
c. a gas.
d. a brittle solid.
e. a liquid.
Answer:
d. a brittle solid.
Explanation:
Hello!
In this case, since cesium fluoride is widely known as an ionic compound due to the large electronegativity difference, it is possible to discard a. due to its crystalline structure, b. because conducting solids are metals, c. because ionic compounds are not likely to be gases and e. because even when it is soluble in water, the problem is not referring to an aqueous solution; therefore, the answer is d. a brittle solid.
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