Answer:
From the given equation, we can see that for every 2 moles of Al, we get 3 moles of H2
So, we can say the the number of moles of H2 is 3/2 times the number of moles of Al
We are given the number of moles of Al and we have to find the number of moles of H2
We have deduced the relationship:
Moles of Al * 3 / 2 = Moles of H2
Replacing the variables with given values
3.5 * 3 / 2 = Moles of H2
Moles of H2 = 5.25 moles
In a fluorine atom, on which energy level are the valence electrons found?
Answer:
second energy level
Explanation:
Valence electrons are those electrons which are present in outer most orbital of the atom.
This can be easily found through the electronic configuration of atom.
Electronic configuration of F:
F₉ = 1s² 2s² 2p⁵
We can see that the valence electrons are present in second energy level of F atom.
There are seven valence electrons of fluorine.
It is called halogens.
Halogens are very reactive these elements can not be found free in nature. Their boiling points also increases down the group which changes their physical states. i.e fluorine is gas while iodine is solid.
Fluorine:
1. it is yellow in color.
2. it is flammable gas.
3. it is highly corrosive.
4. fluorine has pungent smell.
5. its reactions with all other elements are very vigorous except neon, oxygen, krypton and helium.
what's the summary of matter
matter is anything that has mass and volume...it has three state thus solid, liquid and gas.. It possess chemical and physical changes.
noble gas notation for titanium
Answer:
Titanium [Ar] 3d2 4s2
Explanation:
Calculate the pH of a solution containing a caffeine concentration of 455 mg/L . Express your answer to one decimal place.
Answer:
Explanation:
Caffeine is a weak base with pKb = 10.4
Kb = 10⁻¹⁰°⁴ = 3.98 x 10⁻¹¹
molecular weight of caffeine = 194.2
455 x 10⁻³ g / L = 455 x 10⁻³ / 194.2 moles / L
concentration of given solution a = 2.343 x 10⁻³ M
Let the caffeine be represented by B .
B + H₂O = BH + OH⁻
a - x x x
x² / ( a - x ) = Kb
x² / ( a - x ) = 3.98 x 10⁻¹¹
x is far less than a so a -x is almost equal to a
x² = 3.98 x 10⁻¹¹ x 2.343 x 10⁻³ = 9.32 x 10⁻¹⁴
x = 3.05 x 10⁻⁷
[ OH⁻ ] = 3.05 x 10⁻⁷
pOH = - log ( 3.05 x 10⁻⁷ )
= 7 - log 3.05
= 7 - 0.484 = 6.5
pH = 14 - 6.5 = 7.5
The pH of 455 mg/L of caffeine is 7.5
Using the formula;
Mass concentration = molar concentration × molar mass
Molar mass of caffeine = 194 g/mol
Mass concentration of caffeine = 455 mg/L
Molar concentration = Mass concentration/molar mass
Molar concentration = 455 × 10^-3g/L/194 g/mol
= 0.00235 M
Let Caffeine by depicted by the general formula BH
We can now set up the ICE table as follows;
:B + H2O ⇄ BH + OH^-
I 0.00235 0 0
C - x +x +x
E 0.00235 - x x x
Note that water is present in large excess
Again; pKb of caffeine =10.4
Kb = Antilog[-pKb]
Kb = Antilog [-10.4]
Kb = 3.98 × 10^-11
Kb = [BH] [OH^-]/[:B]
3.98 × 10^-11 = [x] [x]/[ 0.00235 - x ]
3.98 × 10^-11 [ 0.00235 - x ] = [x] [x]
9.4 × 10^-14 - 3.98 × 10^-11x = x^2
x^2 + 3.98 × 10^-11x - 9.4 × 10^-14 = 0
x = 3.1 × 10^-7 M
Recall [BH] = [OH^-] = 3.1 × 10^-7 M
Now;
pOH = - log [OH^-]
pOH = log [3.1 × 10^-7 M]
pOH = 6.5
But;
pH + pOH = 14
pH = 14 - pOH
pH = 14 - 6.5
pH = 7.5
The pH of 455 mg/L of caffeine is 7.5
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Missing parts
Caffeine (C8H10N4O2) is a weak base with a pKb of 10.4. Calculate the pH of a solution containing a caffeine concentration of 455 mg/L.
Radiation is transferring thermal energy by=
circulating fluids
touching/physical contact
electromagnetic waves
none of the above
which one is correct
informative essay on bohrs Thomson's and rutherford model of the atom
Use the drop-down menu to complete the statement.
Atoms of elements in the same group have the same number of
. This is why they have similar chemical properties.
Answer:
valence electrons
Explanation:
other guy was close enough
Atoms of elements in the same group have the equal number of valence electrons. That is why they have similar chemical properties.
Why does the element in the same group have similar chemical behavior?The chemical properties of elements depend on the number of valence electrons in their outermost shell. Those elements which are placed in the same group in the periodic table have the same number of valence electrons.
Therefore, elements present in the same group of the modern periodic table have similar chemical behavior.
The elements having a similar valence shell electronic configuration in their atoms are arranged in the same group of the periodic table. These valence electrons decide the chemical properties and reactivities of the chemical elements.
For example, all the elements in group 1 of the periodic table have one electron in their valence shell and all the elements present in group 17 have seven electrons in their valence shell.
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On average, about ____________ of incoming solar radiation is reflected back to space.
A 50%
B 30%
C 20%
D 10%
When an aqueous sodium hydroxide solution of sodium benzoate is acidified, what precipitate is formed, and why does it precipitate?
Answer:
Insoluble benzoic acid is formed
Explanation:
When benzoic acid is dissolved in sodium hydroxide solution, sodium benzoate is formed. This compound is highly soluble in the aqueous layer.
If this solution is now acidified, the equilibrum position shifts towards the undissociated benzoic acid and a precipitate appears.
An insoluble substance formed during crystallization or precipitation is called a precipitate. The precipitate of the reaction formed is of benzoic acid.
What is a precipitation reaction?A precipitation reaction is a type of reaction in which an insoluble salt or substance is formed as the result of the reaction between the soluble salt solutions.
The substance or the salt produced that does not get dissolved in the solution is called a precipitate.
In the reaction, benzoic acid reacts with the sodium hydroxide salt and forms sodium benzoate salt as shown,
[tex]\rm C_{6}H_{5}COOH(s) + NaOH(aq) \rightarrow C_{6}H_{5}COO^{-}Na^{+}(aq) + H_{2}O(l)[/tex]
When the salt of sodium benzoate is acidified then the precipitation of benzoic acid is formed. The precipitate occurs because the equilibrium shifts towards the undissociated benzoic acid.
Therefore, a precipitate of benzoic acid is formed.
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what happens to the temperature of the liquid in a cup of water as some of the water evaporates?
What is the Lewis dot structure for SiS2
Answer:
What Is The Molecular Shape Of A Silicon Disulfide Molecule, SiS2 Trigonal Planar None Of Above Tetrahedral Linear Bent Trigonal Pyramidal 13.
Explanation:
The Lewis structure of SiS₂ shows the 4 valence electrons of Si, which are shared with each sulphur atoms and sulphur in turn shares two valence electrons with Si atom.
What is Lewis dot structure ?The Lewis dot structure of a compound shows all the valence electrons as dots around its atom. From the dot structure we can identify, which electron pairs are bonded , which are non-bonded and which are unpaired electrons.
SiS₂ is a covalent compound formed through the electrons sharing between two sulphur and one silicon atoms. The silicon atom contains 4 valence electrons and one sulphur atom contains 6 valence electrons.
Si needs to gain 4 electrons and one S atom needs to gain 2 more electrons into their valence shell to achieve octet. Hence, One Si shares two electron to each S and S in turn shares its two electron with Si as shown in the image below.
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Define waves in your own words.
Answer:
Waves is the disturbance or variation that transfer energy from one location to other
Answer:
this is not in my words but i think this will help
(put some of the words you would use in this)
Explanation:
Transverse waves are always characterized by particle motion being perpendicular to wave motion. A longitudinal wave is a wave in which particles of the medium move in a direction parallel to the direction that the wave moves. ... Longitudinal waves are always characterized by particle motion being parallel to wave motion.
hope i helped
The specific heat of silver is 0.235 J/gx °C. How much heat is needed to raise the temperature of an 8-gram silver ring by 50°C
Answer:
Heat needed to increase the temperature by 50°C is 94 j.
Explanation:
Given data:
Specific heat of silver = 0.235 j/g.°C
Heat needed to increase temperature = ?
Mass of silver = 8 g
Temperature difference = ΔT= 50°C
Solution:
Formula:
q = mcΔT
c = specific heat capacity of substance
Now we will put the values i formula.
q = 8 g× 0.235 J/g.°C× 50°C
q = 94 J
Heat needed to increase the temperature by 50°C is 94 j.
All of the following conditions in Earth can cause metamorphic rock to form EXCEPT
O pressure
O heat
the presence of hot, plastic like material
O exposure to air
Explanation:
heat
the presence of hot, plastic like material
convert 575.1 mmHg to atm
Answer:
= .7567105263
Explanation:
1 atm = 760 mmHg
575.1 mmHg (1 atm/760mmHg) = .7567105263 atm
Ten moles of hydrogen are allowed to react with 6 moles of oxygen. How much water will be
obtained from reaction on complete consumption of one gas?
Answer:
10 moles of water are produced,
Explanation:
Given data:
Moles of H = 10 mol
Moles of O = 6 mol
Water obtained = ?
Solution:
Balance chemical equation:
2H₂ + O₂ → 2H₂O
Now we will compare the moles of H₂ and O₂ with water from balance chemical equation.
H₂ : H₂O
2 : 2
10 : 10
O₂ : H₂O
1 : 2
6 : 2×6 = 12
Number of moles of water produced by hydrogen are less so hydrogen will be limiting reactant and it will limit the yield of water thus, 10 moles of water are produced.
which describes bedrock?
a. consist of a solid rock
b.lies directly above the soil layer
c, does not contain weathered rock
d. forms from decomposed material
Please tell me the answers to A, B, and C
Answer:
A=element
B=compond
C=solution
PLSSS HELP Match each image to the
correct step of meiosis. PLS HELP
Answer:
Explanation:
Here you go!! Hope this helps.
Which part of the cell contains DNA?
Golgi body
mitochondrion
nucleus
vacuole
quick
Answer:
Nucleus
Explanation:
The nucleus because it is basically the control system for the cell.
Answer:
Explanation:
Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).
https://medlineplus.gov/genetics/understanding/basics/dna/
(ii) What is the approximate chlorine-carbon-chlorine bond angle in C2Cl4?
Answer:
∠
O
−
C
−
C
l
≅
120
∘
The central carbon is
s
p
2
−
hybridized........
Explanation:
And thus
∠
C
l
−
C
−
C
l
and
∠
O
−
C
−
C
l
≅
are
120
∘
to a first approximation.
Why this value? We look to
VSEPR theory
. There are 3 regions of electron density around the central carbon, and the most stable geometry is a trigonal plane. While there is a
carbonyl
group, i.e. a
C
=
O
bond, the
π
bond is conceived to lie above and below this trigonal plane.
The
carbonyl oxygen
is likewise conceived to be
s
p
2
-hybridized
, however, here, there are 2 lone pairs on the oxygen centre.
The approximate chlorine-carbon-chlorine bond angle in C2Cl4 is 120°.
The bond angle is defined as the angle between ant two bonds emanating from a common atom.
The compound C2Cl4 is tetrachloroethene. The carbon atoms are sp2 hybridized in this molecule.
Recall that the bond angle of an sp2 hybridized carbon atom is 120°. Therefore the chlorine-carbon-chlorine bond angle in C2Cl4 is 120°.
From the perspective of the VSEPR theory, the geometry of each carbon atom in C2Cl4 is trigonal planar which implies a bond angle of 120°.
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Explain How does its structure affect its function
Answer:
What are we talking about here?
Explanation:
Given the following equation:
4 NH_3(g) + 5 O_2(g) → 4 NO(g) + 6 H_2O(l)
How many grams of H_2O is produced if 66.60 grams of NO is produced?
What is the predictable process in which one element type is converted into a new form?Immersive Reader
(10 Points)
A. Law of Superposition
B. Igneous formation
C. Fossil formation
D. Radioactive decay
Answer:
Radioactive decay
Explanation:
Answer:
D. Radioactive decay
Explanation:
23994Pu + 10n → BCBa + 9138Sr + 3 10n
B=??
a
150
b
100
c
140
d
146
Answer:
the answer to this question is c 140
Describing different types of waves. Which statement describes the wave? Check all that apply
Answer:
A. the wave is a mechanical wave
C. the wave moves energy through matter
F: the wave transfers energy perpendicular to the motion of the wave.
PLEASE HELP, WILL MARK BRAINLIEST!
The best way to find the volume of an empty bottle is to...
a) weigh the bottle and record the mass, then add the water and subtract its mass from that of the empty bottle
b) fill the bottle with water and place it on a balance
c) fill the bottle with water, and then empty the water into a graduated cylinder.
Answer:
C
Explanation:
Which of the following correctly lists the five atoms in order of increasing size (smallest to
largest)?
O, F, Mg, S, Ba
Answer:
F - O - S - Mg - Ba
Explanation:
as you move left to right on the periodic table the number of electrons increase.
The correct lists of the five atoms in order of increasing size smallest to
largest is :
D) F - O - S - Mg - Ba
Atomic RadiusThe correct lists of the five atoms in order of increasing size smallest to
largest is F - O - S - Mg - Ba.
The atomic radius of a chemical element may be a degree of the measure of its molecule, as a rule the mean or commonplace remove from the center of the core to the furthest isolated electron.
The arrange will be:
Fluorine(F) (50 pm)Sulfur(S) (100 pm) Magnesium(Mg) (150 pm) Barium(Ba) (215 pm)As you move cleared out to right on the periodic table the number of electrons increment.
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A sailor on a trans-Pacific solo voyage notices one day that if he puts 375. mL of fresh water into a plastic cup fresh water weighing 15.0 g, the cup floats in the seawater around his boat with the fresh water inside the cup at exactly the same level as the seawater outside the cup.
Required:
Calculate the amount of salt dissolved in each liter of seawater.
Answer:
Amount of salt dissolved in each liter of seawater = 40 g
Explanation:
According to Archimedes principle, a body will float in a fluid if the upthrust experienced by a body is equal to the to the weight of the body.
Also, the volume of seawater displaced equals the volume of freshwater in the cup.
From the above principle, since the freshwater and cup floats in the seawater, their combined weight equals the upthrust.
Therefore, mass of equal volume of displaced seawater = mass of freshwater + mass of cup
Mass of freshwater = density of freshwater * volume
density of freshwater = 1 g/mL; volume = 375 mL
mass of freshwater = 375 mL * 1 g/mL = 375 g
mass of seawater = 375 + 15 = 390 g
mass of salt in 375 mL seawater = mass of seawater - mass of freshwater
mass of salt = (390 - 375) g = 15 g
Since 15 g of salt are dissolved in 375 mL seawater, mass of salt in 1 L of seawater =(1000 mL/ 375) * 15g = 40 g
Therefore, amount of salt dissolved in each liter of seawater = 40 g
8 You are given 20.00g of a dry mixture of sand and table salt.
After adding water and filtering, you are left with wet sand on
the filter paper. The filter paper and sand is then dried and the
mass of the dry sand alone is found to be 5.00g. What was the
% sand in the original mixture?
Answer:
[tex]\%sand=25\%[/tex]
Explanation:
Hello.
In this case, given the mass of the mixture, we can define it in terms of the mass of sand and table salt as shown below:
[tex]m_{sand}+m_{salt}=20.00g[/tex]
Moreover, as after filtering, the mass of dry sand turns out 5.00 g, we can compute the % sand in the original mixture by dividing this value over the mass of the mixture as shown below:
[tex]\%sand=\frac{m_{sand}}{m_{mixture}}*100\%\\ \\\%sand=\frac{5.00g}{20.00g}* 100\%\\\\\%sand=25\%[/tex]
Best regards!