Answer:
C. 21%oxygen
Explanation:
Dry air contains 78.09% nitrogen, 20.95%oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases.
Lewis dot diagram for the Cs1+ ion
Answer:
[tex]Cs^+[/tex]
Explanation:
Cesium Lewis dot structure would look like this:
·Cs, because it only has one valence electron. But, since it has a plus, that means we lost an electron. So, we have to get rid of the dot and you have:
[tex]Cs^+[/tex]
hi!! can somebody help me with this question?
which is the best example of commensalism?
A. honey bees feed on the pollen of cornflowers and help the flowers reproduce
B. barnacles ride on a gray whales back to obtain food, and the whale is not harmed
C. squirrels and chipmunks eat the same nuts in a forest where food is scarce
D. prairie dogs often collect and eat food in groups so they are better protected from enemies
thx to anybody that helps! ♡︎
Answer:
B: Barnacles ride on a gray whale's back to obtain food, and the hale is not harmed.
Explanation:
I got it right on Edge.
What BEST describes the relation of a new population to an increase in the amount of space it occupies? a - The population will die out
b - The population will remain constant
c - The population will grow exponentially
adaptive features of aquatic plants
oil has a density of 8.5kg/L. what is the volume of 5.4kg oil
Answer:
0.64 L
Explanation:
Step 1: Given data
Density of oil (ρ): 8.5 kg/LMass of oil (m): 5.4 kgVolume of oil (V): ?Step 2: Calculate the volume corresponding to 5.4 kg of oil
Density is an intrinsic property and it is equal to the quotient between the mass and the volume.
ρ = m/V
V = m/ρ
V = 5.4 kg/(8.5 kg/L) = 0.64 L
A triangle has one angle that measures 81° and one that measures 37° what is the measure of a third angle
? I JUST DONT UNDERSTAND
Answer:
5SiO2 + 2CaC2 → 5Si + 2CaO + 4CO2
Explanation:
When you are balancing an equation, you use coefficients to change the number of atoms of each type that are on each side of the equation.
You cannot change subscripts, the small numbers to the right of the substances. You can only add coefficients, the large numbers to the left of substances.
A balanced equation has the same number and type of atoms on both sides of the equation (the reactants on the left, the products on the right).
To begin, this equation has:
1 Si
2 O
1 Ca
2 C
on the left and
1 Si
1 Ca
3 O
1 C
on the right. Those numbers don't match!
By adding coefficients we end up with 5 Si, 10 O, 2 Ca and 4 C on both sides.
A student mixes 5.00 mL of 0.0020 M Fe(NO3)3 with 3.00 mL of 0.0020 M KSCN solution and 2.00 mL water at a certain temperature. He places a sample of the resulting solution in a spectrometer, and measures the transmittance as 23% at 447 nm. What are the initial concentrations of [Fe3 ] and [SCN-]
Answer:
[Fe⁺³] = 0.0010 M
[SCN⁻] = 0.0006 M
Explanation:
First we calculate how many moles of Fe⁺³ and SCN⁻ were added, using the given volumes and concentrations:
Fe⁺³ ⇒ 5.00 mL * 0.0020 M = 0.010 mmol Fe⁺³SCN⁻ ⇒ 3.00 mL * 0.0020 M = 0.006 mmol SCN⁻Now we can calculate the initial concentrations, after calculating the new volume of the solution:
New volume = 5.00 mL + 3.00 mL + 2.00 mL = 10.00 mL[Fe⁺³] = 0.010 mmol / 10.00 mL = 0.0010 M[SCN⁻] = 0.006 mmol / 10.00 mL = 0.0006 MWhat is the final volume?
Answer:
Option A. 9.4 L
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 8 L
Initial temperature (T₁) = 293 K
Final temperature (T₂) = 343 K
Final volume (V₂) =?
V₁ / T₁ = V₂ / T₂
8 / 293 = V₂ / 343
Cross multiply
293 × V₂ = 8 × 343
293 × V₂ = 2744
Divide both side by 293
V₂ = 2744 / 293
V₂ = 9.4 L
Therefore, the final volume of the gas is 9.4 L
The nucleus of an atom stays together only because the repulsive forces, called
forces, are overcome by
even stronger attractive forces.
fusion
nuclear
electrostatic
Answer:
Electrostatic
Explanation:
The forces that are overcome are the repulsive electrostatic forces between the protons (all charged positively).
The equation below illustrates the process of
Pb2+ (aq) + 11- (aq) → Pblu (s)
a) dissolution
b) precipitation
c) decomposition
Answer:
The correct answer is - b) precipitation.
Explanation:
In the given question the lead ion in an aqueous solution is mixed with the Leutium ion in an aqueous solution and forms an insoluble or solid salt. This type of reaction is referred to as precipitation reactions in chemistry.
Such reactions are helpful in determining if a particular ion is present in the solution or not.
Pb2+ (aq) + lu- (aq) → Pblu (s)
A vitamin C (ascorbic acid) tablet was dissolved in approximately 50 mL of distilled water and titrated with the standardized NaOH solution. From the results of this titration, the mg of ascorbic acid in the tablet was calculated. Molecular formula of ascorbic acid: C6H8O6 Volume of NaOH required to neutralize ascorbic acid in Vitamin C tablet (mL) 20.74 Concentration of NaOH in mol/L, 0.201 Calculate the amount of ascorbic acid in the Vitamin C tablet in (mg).
Answer:
The correct answer is - 733.69 mg.
Explanation:
given:
The volume of ascorbic acid = 50 ml
The volume of NaOH = 20.74 ml
Molarity of NaOH = 0.201 M
formula = C6H8O6
Solution:
moles of NaOH for titration = molarity of NaOH × The volume of NaOH
= 0.201 × 20.74 × 10^-3
=4.16874 × 10^-3
then molecular weight of ascorbic acid
= 6 × 12+ 8×1+ 6× 16
=176g/mol
the molecular mass would be
= 4.16874 × 10^-3 × 176
= 733.69 × 10^-3 g
=733.69 mg
If you began a reaction with the following ions in solution, what would be the net ionic equation?
Na+, PO43–, Fe2+, and NO3–
Answer:
2 PO₄³⁻(aq) + 3 Fe²⁺(aq) ⇒ Fe₃(PO₄)₂
Explanation:
Let's consider the complete ionic equation between the ions present. It includes all the ions and the insoluble compounds (Fe₃(PO₄)₂ is insoluble).
Na⁺(aq) + 2 PO₄³⁻(aq) + 3 Fe²⁺(aq) + NO₃⁻(aq) ⇒ Fe₃(PO₄)₂ + Na⁺(aq) + NO₃⁻(aq)
The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the insoluble compounds.
2 PO₄³⁻(aq) + 3 Fe²⁺(aq) ⇒ Fe₃(PO₄)₂
State the coefficient required to correctly balance the following chemical equation:
__KCI + __Fe —-> __FeCI2+ __K
Answer:
2KCl+Fe---->FeCl2+2K
Explanation:
You can observe that the no.of atoms in reactant side is equal to that of products side of each element.
How many atoms are in 90.43 moles of copper
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 8.12×10²³ atoms are in 90.43 mole of copper.
What is mole?
The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity of amount of substance. It measure the number of elementary entities of a given substance that are present in a given sample. There are so many formula for calculating mole.
we know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number
number of atoms/molecules=number of moles × 6.022×10²³(Avogadro number)
number of moles of copper=90.43 moles
Substituting all the given values in the above equation, we get
number of atoms/molecules= 90.43 × 6.022×10²³
number of atoms/molecules=8.12×10²³ molecules
Therefore, 8.12×10²³ atoms are in 90.43 mole of copper.
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What will happen if HI is removed from a reaction vessel containing this
reaction at equilibrium?
H2+ 12 22H1
A. The reaction will slow down.
B. There will be no effect.
C. The rate of the forward reaction will increase.
D. The rate of the backward reaction will increase.
SUBMIT
Answer:
C I think
Explanation:
There will be no effect if HI is removed from a reaction vessel containing this reaction at equilibrium. When HI remove, concentration of all three component is change and reach a new equilibrium stage.
H2 + I2 ⇄ 2HI
So, B is correct option.
What is equilibrium?The stage in reversible reaction at which rate of forward reaction is equal to rate of backward reaction is equal is called an equilibrium.
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4. What is the specific heat of a substance if 5800 joules is
released in a 250 gram sample that will cool the substance from
60 degrees to 45 degrees?
Answer: 23.2
Explanation:
What does synthesis gas (water gas) consist of?
Answer:
ch4+h2o----725°-->co+2h2
What volume of 1.75 M hydrochloric acid (HCl aq) must be diluted with water to prepare 0.500 L of 0.250 M hydrochloric acid?
Answer:
[tex]V_1=0.0714L[/tex]
Explanation:
Hello there!
In this case, since we need to dilute the 1.75-M HCl, and the total number of moles remain unchanged, we can write:
[tex]n_1=n_2[/tex]
And in terms of volume and concentration:
[tex]C_1V_1=C_2V_2[/tex]
Thus, we can solve for the volume of the concentrated HCl as shown below:
[tex]V_1=\frac{C_2V_2}{C_1}[/tex]
Therefore, we plug in the data to get:
[tex]V_1=\frac{0.250M*0.500L}{1.75 M}\\\\V_1=0.0714L[/tex]
Best regards!
Pls help me over here
Answer:
1 and the element is hydrogen (there is an exception for the octet rule for the element hydrogen) hope this helps
Explanation:
An empty steel container is filled with 2.0 atm of H₂ and 1.0 atm of F₂. The system is allowed to reach equilibrium according to the reaction below. If Kp = 0.45 for this reaction, what is the equilibrium partial pressure of HF?
The equilibrium partial pressure of HF is 0.55 atm.
The equation of the reaction is;
H2(g) + F2(g) ⇄ 2HF
I 2 1 0
C -x -x +x
E 2 - x 1 - x x
We know that;
pH2 = 2.0 atm
PF2 = 1.0 atm
pHF = ??
Kp = 0.45
So;
Kp = (pHF)^2/pH2. pF2
0.45 = x^2/(2 - x) (1 - x)
0.45 = x^2/x^2 - 3x + 2
0.45(x^2 - 3x + 2) = x^2
0.45x^2 - 1.35x + 0.9 = x^2
0.55 x^2 + 1.35x - 0.9 = 0
x = 0.55 atm
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Put the following type of radiations in order of increasing energy: red, radio, UV, infrared, blue, and x-ray
Answer: The order of increasing energy is: radio < infrared < red < blue < UV < x rays
Explanation:
Electromagnetic wave is defined as the wave which is associated with both electrical and magnetic component associated with them.
The electromagnetic radiations consist of gamma rays , X rays , Ultraviolet , Visible , Infra red , microwaves and radio waves arranged in order of decreasing frequency and increasing wavelengths. The visible region consists of violet , indigo , blue , green , yellow, orange and red lights in order of decreasing frequency or increasing wavelength
The relationship between energy and frequency of the wave follows the equation:
[tex]E=h\times \nu[/tex]
where,
[tex]\nu[/tex] = frequency of the wave
E = energy of wave
From the above relation, it is visible that energy and frequency follow direct relation. For increase in value of frequency, energy increases and vice-versa.
Thus the order of increasing energy is: radio < infrared < red < blue < UV < x rays
Draw the structure formula for
1-ethyl-2,3-dimethylbenzene
Please help me
Answer:
Please see the attached picture.
Explanation:
1) Draw a benzene ring
2) On the first carbon, add a CH₂CH₃ (known as ethyl) since its location number is 1.
3) 'Dimethyl' refers to 2 methyl (CH₃) branches. The location numbers are 2 and 3, thus add a CH₃ on the 2nd and 3rd carbons.
3. Define the term zwitterion. Draw the structure of alanine and explain why this molecule is a
zwitterion in certain conditions.
Answer:
A zwitterion or a hybrid ion is an ion that has both a positive and negative charge and can act as either a base or an acid.
Explanation:
A zwitterion or a hybrid ion is an ion that has both a positive and negative charge and can act as either a base or an acid. The net charge on a zwitterion is zero since it has equal number of positive and negative charges.
Alanine, is a monoamino monocarboxylica acid that is diprotic when fully protonated. The carboxylic acid group, COOH and the amino group, NH₃⁺, are able to produce one proton each. At a pH equal to the isoelectric point of alanine, it exists mainly in the zwitterionic form with the α-amino group protonated as NH₃⁺ and the α-carboxyl group deprotonated as COO⁻ . This is because at the isoelectric point of alanine (6.0), pI is greater than the acid dissociation constant, pKa of the α-carboxyl group whereas, pI is less than the acid dissociation constant, pKa of the α-amino group, so the two groups are negatively and positively charged respectively.
Do you think humans are responsible for global warming trends? Why or why not?
Answer:
Yes. At least some. There has been ups and downs in temperature ever since the Earth was created, and this is just another up in temperature. I do think that humans have made it worse though, with all of the greenhouse gases and things like that.
Determine if the following two structures are
identical, isomers, or unrelated?
A
B
С
identical
isomers
unrelated
Answer:
its C
Explanation:
The skeletal structure shows the outline of the compound with lines and bonds. Both the structures are unrelated. Thus, option C is correct.
What are isomers?Isomers are structures with identical molecular structures but differ in the skeletal or molecular representation. They also have varied properties as compared to the parent structure.
Identical compounds are structures that have the same atoms and are arranged with the same spatial design and orientation. The number of atoms and the spatial arrangement of the two compounds is different.
Therefore, the two compounds are unrelated.
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One of the following is not a physical property of iron.
Mark only one oval.
malleability
magnetism
rusting
color
Answer:
Rusting
Explanation:
Rusting is oxidizing iron, which would be a chemical property.
Given 1.67 moles of K, how many moles of KBr are produced?
2 K+ 1 Br2---> 2 KBr
[tex]\displaystyle 1.67 \ mol \ KBr[/tex]
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
BracketsParenthesisExponentsMultiplicationDivisionAdditionSubtractionLeft to RightChemistry
Atomic Structure
MolesStoichiometry
Using Dimensional AnalysisAnalyzing Reactions RxNExplanation:Step 1: Define
[RxN - Balanced] 2K + Br₂ → 2KBr
[Given] 1.67 moles K
[Solve] moles KBr
Step 2: Identify Conversions
[RxN] 2 mol K → 2 mol KBr
Step 3: Stoichiometry
[DA] Set up conversion: [tex]\displaystyle 1.67 \ mol \ K(\frac{2 \ mol \ KBr}{2 \ mol \ K})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 1.67 \ mol \ KBr[/tex]Ammonia can be made by reaction of water with magnesium nitride as shown by the following unbalanced equation: Mg3N2(s) + H2O(l) Mg(OH)2(s) + NH3(g) If this process is 71% efficient, what mass of ammonia can be prepared from 24.5 kg magnesium nitride?
The mass of ammonia prepared from 24.5 kg magnesium nitride, according to the reaction Mg₃N₂(s) + 6H₂O(l) → 3Mg(OH)₂(s) + 2NH₃(g), knowing that the process is 71% efficient is 5.87 kg.
The balanced reaction of production of ammonia is:
Mg₃N₂(s) + 6H₂O(l) → 3Mg(OH)₂(s) + 2NH₃(g) (1)
First, let's find the number of moles of magnesium nitride
[tex] n_{Mg_{3}N_{2}} = \frac{m_{Mg_{3}N_{2}}}{M_{Mg_{3}N_{2}}} [/tex] (2)
Where:
[tex]m_{Mg_{3}N_{2}}[/tex]: is the mass of Mg₃N₂ = 24.5 kg
[tex]M_{Mg_{3}N_{2}}[/tex]: is the molar mass of Mg₃N₂ = 100.9494 g/mol
The number of moles is (eq 2):
[tex] n_{Mg_{3}N_{2}} = \frac{m_{Mg_{3}N_{2}}}{M_{Mg_{3}N_{2}}} = \frac{24500 g}{100.9494 g/mol} = 242.70 \:moles [/tex]
We can calculate the mass of ammonia prepared, knowing that 1 mol of Mg₃N₂ reacts with 6 moles of H₂O to produce 3 moles of Mg(OH)₂ and 2 moles of NH₃ (reaction 1).
[tex]n_{NH_{3}} = \frac{2\: moles\: NH_{3}}{1\: mol\: Mg_{3}N_{2}}*n_{Mg_{3}N_{2} = \frac{2\: moles\: NH_{3}}{1\: mol\: Mg_{3}N_{2}}*242.70 \:moles \:Mg_{3}N_{2} = 485.4 \:moles[/tex]
Then, the mass of NH₃ is:
[tex] m_{NH_{3}} = n_{NH_{3}}*M_{NH_{3}} = 485.4 \:moles*17.031 g/mol = 8266.8 g = 8.27 kg [/tex]
Since the process is 71% efficient, the mass that can be prepared is:
[tex] m = 8.27 kg*0.71 = 5.87 kg [/tex]
Therefore, the mass of ammonia that can be prepared is 5.87 kg.
I hope it helps you!
Compare the change in pH with the addition of acid and base to deionized water and to a buffer.
Answer:
case1.
The addition of acid and base leads to a change in pH of the water when adding to deionized water due to fact that acid and bases dissociated in dissolving in water. If the H+ ion increases in the water as acid addition hikes it, it will result in decreasing the pH value. The intensity of the acid also affects the dissociation of the ions.
case2
Buffers are normally formed by weak acid and its conjugate base, and adding acid to the buffer it absorbs the H+ ions so the pH will be lower and adding base or increase of OH- conjugate base resists the pH value to increase.