Answer:
Explanation:
You have given the exact definition of what an atom is. It is the smallest entity that has all the same properties as a bunch of atoms put together.
If an object absorbs all the light that hits it, the object appears to be
1. What is the specific heat of a substance that requires 270 J of energy to raise the temperature of 4.2 grams by 25°C?
Heat required is mcΔT=100×0.39×50=1950 J
Solve any question of Thermodynamics with:-
The specific heat of the substance that requires 270 J of energy to raise the temperature is 2.57 J/g⁰C.
Specific heat capacity of the substanceThe specific heat capacity of the substance is calculated as follows;
Q = mcΔФ
where;
c is the specific heat capacityc = Q/mΔФ
c = (270) / (4.2 x 25)
c = 2.57 J/g⁰C
Thus, the specific heat of the substance that requires 270 J of energy to raise the temperature is 2.57 J/g⁰C.
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11. If a hypothetical element consisted of three isotopes in the following relative abundance, what would the atomic
mass of the element be?
30.00% 30.00 amu
50.00% 32.00 amu
20.00% 35.00 amu
A. 33.00 amu
B. 32.25 amu
C. 32.00 amu
D. 31.50 amu
E. 31.00 amu
Answer:
hiroghlipical
Explanation:
new word i just made
Calculate the energy of a photon of light emitted from a hydrogen atom when an electron falls from level n
Answer: E
1
−
E
4
=
Δ
E
=
−
2.18
×
10
−
18
J
(
1
n
2
f
−
1
n
2
i
)
=
−
2.18
×
10
−
18
J
(
1
1
2
−
1
4
2
)
=
−
2.18
×
10
−
18
J
(
15
16
)
=
−
2.04
×
10
−
18
J
After you obtain the energy, then you can realize that that energy has to correspond exactly to the energy of the photon that came in:
|
Δ
E
|
=
E
photon
=
h
ν
=
h
c
λ
where
h
is Planck's constant,
c
is the speed of light, and
λ
is the wavelength of the incoming photon. Thus, the wavelength is:
⇒
λ
=
h
c
E
photon
=
(
6.626
×
10
−
34
J
⋅
s
)
(
2.998
×
10
8
m/s
)
2.04
×
10
−
18
J
=
9.720
×
10
−
8
m
=
97.20 nm
Explanation:
During ionization, metals lose electron, this change is called?
Ans
This is called oxidation
Explanation:
the oxidation number of a metal ion is more than the oxidation number of metal atom
An ion of iron has an 26 protons, 30 neutrons, and 23 electrons. What are its atomic number, atomic mass, and net charge?
Answer:
Atomic number: 26
Atomic mass: 56
Net charge: +3
Explanation:
a car accelerates from rest(zero speed) up to a spees of m/s to a speed of 30 m/s in 12 seconds. calculate the acceleration.
how many grams of lead (ii) iodide will be precipitated by adding sufficient Pb(NO3)2 to trace with 630mL of 0.268M Ki solution?
2KI(aq)+Pb(NO3)2(aq) → PbI2+2KNO3(aq)
The mass of PbI2 produced from a trace amount of 630mL of 0.268M KI solution is 39.2 g.
The equation of the reaction is; 2KI(aq)+Pb(NO3)2(aq) → PbI2(s) + 2KNO3(aq)
From the question, number of moles of KI = 630/1000 L × 0.268M = 0.169 moles
Now;
2 moles of KI is required to precipitate 1 mole of PbI2
0.169 moles of KI is required to precipitate 0.169 moles × 1 mole/2 moles
= 0.085 moles
Mass of PbI2 = Number of moles of PbI2 × Molar mass
Mass of PbI2 = 0.085 moles × 461.01 g/mol
Mass of PbI2 = 39.2 g
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What is the relationship between Avogadro number, mole, and mass number?
1. Which of these is an agent of chemical weathering?
copper patina
iron oxide
acid rain
iron
Answer:
Test answers
1. Water carving out a limestone cave
2. Oxidation
3. Acid rain
(Got 100%)
Explanation:
The primary agents of chemical weathering are water, oxygen and acids. So acid rain is an agent of chemical weathering. Option C is correct.
Which are the agents of chemical weathering ?Water, and many chemical compounds found in water, is the main agent of chemical weathering. One of the most abundant rock-forming minerals, chemically reacts with water and water-soluble compounds to form clay.
Water contains many weak acids such as carbonic acid. The primary agents of chemical weathering are water, oxygen and acids.
These react with surface rocks to form new minerals that are stable in, or in equilibrium with, the physical and chemical conditions present at the earth's surface.
Hence, option C is correct.
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A 0.100 g sample of phosphoric acid (H3PO4, MW 99.0 g/mol), a tri-protic acid, requires 35.0 mL of a NaOH solution for neutralization. What is the molarity of the NaOH solution
Answer:
0.0866 M
Explanation:
answer key
The molarity of the NaOH solution has been 0.0865 M.
The neutralization reaction of the Phosphoric acid and NaOH results in the formation of sodium phosphate and water.
The balanced chemical equation can be given as;
[tex]\rm H_3PO_4\;+\;3\;NaOH\;\rightarrow\;Na_3PO_4\;+\;3\;H_2O[/tex]
Thus for the neutralization of 1 mole of Phosphoric acid, 3 moles of NaOH has been used.
The moles of phosphoric acid in 0.100 grams sample:
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of phosphoric acid = [tex]\rm \dfrac{0.100}{99}[/tex]
Moles of phosphoric acid = 0.001 mol
For the neutralization of 0.001 moles of NaOH:
1-mole Phosphoric acid = 3 moles NaOH
0.001-mole Phosphoric acid =0.003 moles of NaOH.
The molarity of the NaOH solution:
Molarity = [tex]\rm \dfrac{moles}{Volume\;(L)}[/tex]
Molarity of NaOH = [tex]\rm \dfrac{0.003}{0.035}[/tex]
Molarity of NaOH = 0.0865 M
The molarity of the NaOH solution has been 0.0865 M.
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Give one example of a pure substance.
Answer:
some example includes:
gold, copper, oxygen, chlorine, diamond
Explanation:
at 25°c the heat of fusion of aluminum is 10.6 kj/mol and the heat of sublimation is 326.4 kj/mol. what is the heat of vaporization of aluminum at 25°c?
The heat of vaporization of aluminium at 25 °C is 315.8 kilojoules per mole.
The sublimation is the phase change of a substance from solid to gas, the fusion is the phase change of a substance from solid to liquid and the vaporization is the phase change of a substance from liquid to gas. The heat of vaporization is the difference between the heat of sublimation and the heat of fusion, that is to say:
[tex]h_{v} = 326.4\,\frac{kJ}{mol}-10.6\,\frac{kJ}{mol}[/tex]
[tex]h_{v} = 315.8\,\frac{kJ}{mol}[/tex]
The heat of vaporization of aluminium at 25 °C is 315.8 kilojoules per mole.
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HELP!!!! I need help with number 11 and 12
Answer:
V1/n1 = V2 /n2
0.236/0.306 = V2/ 4.40
V2 = 3.39 L
calculate the number of moles of ethanol acid in 30 cm³of 1 mol dm-³ solution
Answer:
May I assume "ethanol acid is just ethanol (it has one slightly acidic H atom). If so, the molar mass is 46.02 g/mole.
Explanation:
We have 30 cm^3 [30 ml] of 1.0 M (1 mole/liter) [1 dm³ = 1 liter].
That is 1 mole/liter. 30 ml would contain (0.030 liter)*(1 mole/1 liter) = 0.03 moles.
given that the radiusof anion a2- is 0.290 nm, what would you expect the radius of a and a2+ to be
This problem is providing the ionic radius of an anion, A²⁻ as 0.290 nm and asks for that of the cation A²⁺ in comparison to the former.
Firstly, we need to recall the concept of ionic radius, as the distance between the nucleus and the outermost electron shell of an ion. In such a way, we can have two scenarios:
1. Anions result from the gain of electrons exhibited by a nonmetal, which means they turn out bigger than the neutral atom.
2. Cations result from the loss of electrons exhibited by a metal, which means they turn out smaller than the neutral atom.
With the aforementioned, we infer that the cation A²⁺, will me smaller than the anion A²⁻, which means it will have an ionic radius smaller than 0.290 nm.
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https://brainly.com/question/12026272https://brainly.com/question/19032815Please help!! I don’t know what to do.
Answer:
C
Explanation:
No reaction because not enough moles of silver are present for the reaction to occur.
This element has an atomic number lower than aluminum and is in group 14
Answer:
that is impossible. the atomic number can only go up each group
What is the wavelength, in nm, of the light photon emitted by a hydrogen atom when an electron goes from n
Answer:
Hence, the wavelength of the photon associated is 1282 nm.
Explanation:
Describe how the production of a gas (carbon dioxide) suggests a chemical change
occurred?
Why was the creation of element 114 so special?
Answer:
It is classified as a metal and is expected to be solid at room temperature.
Explanation:
not sure but i guess it is that
The same quantity of each solute is added to water. Which solution will have the greatest number of H30+ ions at equilibrium?
(1 point)
O weak acid
O strong acid
O strong base
O weak base
please anyone please this is due today!! help for a BRAINLIEST
For today's assignment, you need to balance and classify each of the following equations as synthesis, decomposition, single replacement, double replacement, or combustion.
Answer:
Explanation:
Im sorry all i know is that #3 is for sure combustion
Four substances at the same temperature absorb equal
amounts of energy. The specific heat of the four
substances are listed below.
Substance
A. 1.45 J/g °C
B. 2.32 J/g °C
C. 0.98 J/g °C
D. 1.95 J/g °C
Which substance would show the GREATEST increase in
temperature?
A
B
C
D
Answer:
its that DDDDDD
Explanation:
i know this because its that DDDDDDDD
82. How many moles of calcium are in 3.82g of calcium?
how many moles of iron are present in 3.15 × 10^24 atoms of iron?
Answer:
5.23 moles
Explanation:
How many moles of iron are present in 3.15 × 10^24 atoms of iron?
1 mole has 6.02 X 10^23 particles
so
3.15X10^ 24 atoms =( 3.15 X 10^24)/(6.02 X 10^23) =(3.15/6.02 )X 10 =
5.23 moles
How many eggs are in 3 dozen eggs? Use the dimensional analysis for this for practice.
Answer:
36 eggs
Explanation:
12 eggs in each carton
12 + 12 + 12 = 36 eggs
or 3 * 12 = 36 eggs
Hope this helps, have a nice day/night! :D
why don't birds get electrocuted when they land on the electric wire?
Answer:
Birds can sit on power lines and not get electric shocks because the electricity is always looking for a way to get to the ground. The birds are not touching the ground or anything in contact with the ground, so the electricity will stay in the power line.
Pls mark as brainliest answer if it helps you
A sample of H2 gas (12.28 g) occupies 100.0 L at 400.0 K and 2.00 atm. A sample weighing 9.49 g occupies ________ L at 353 K and 2.00 atm.
Considering the ideal gas law, a sample weighing 9.49 g occupies 68.67 L at 353 K and 2.00 atm.
Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:
P× V = n× R× T
In this case, you know:
P= 2 atmV= ?n= [tex]9.49 gramsx\frac{1 mole}{2 grams} = 4.745moles[/tex] being 2g/mole the molar mass of H2, that is, the amount of mass that a substance contains in one mole.R= 0.082 [tex]\frac{atmL}{molK}[/tex]T= 353 KReplacing:
2 atm× V = 4.745 moles× 0.082[tex]\frac{atmL}{molK}[/tex]× 353 K
Solving:
V = (4.745 moles× 0.082[tex]\frac{atmL}{molK}[/tex]× 353 K)÷ 2 atm
V= 68.67 L
Finally, a sample weighing 9.49 g occupies 68.67 L at 353 K and 2.00 atm.
Learn more:
https://brainly.com/question/4147359?referrer=searchResultsWhat's a suitable assumption for a simple distillation lab?
Answer:
Must be stable and relatively insoluble in boiling water.
Explanation:
it must be stable and relatively insoluble in boiling water and a must-have vapor pressure in boiling water that is of the order atmosphere at or more compound satisfy these conditions that will generally not separate from each other but we'll be separated from everything else.