Answer:
For all these questions, we want to find the empirical and molecular formulae of various compounds given their percent composition and molar mass. The technique used to answer one of the questions can accordingly be applied to all of them.
Approaching the first question, we treat the percentages of each element as the mass of that element in a 100 g compound (as the percentages add up to 100%). So, our 100 g compound comprises 7.74 g H and 92.26 g C.
Next, we convert these mass quantities into moles. Divide the mass of each element by its molar mass:
7.74 g H/1.00794 g/mol = 7.679 mol H
92.26 g C/12.0107 g/mol = 7.681 mol C.
Then, we look for the molar quantity that's the smallest ("smaller," in this case, since there are only two), and we divide all the molar quantities by the smallest one. Here, it's a very close call, but the number of moles of H is slightly smaller than that of C. So, we divide each molar quantity by the number of moles of H:
7.679 mol H/7.679 mol H = 1
7.681 mol C/7.679 mol H ≈ 1 C/H (the value is actually slightly larger than 1, but we can treat it as 1 for our purposes).
The quotients we calculated represent the subscripts of our compound's empirical formula, which should provide the most simplified whole number ratio of the elements. So the empirical formula of our compound is C₁H₁, or just CH.
Here, it just so happens that we obtained whole number quotients. If we end up with a quotient that isn't a whole number (e.g., 1.5), we would multiply all the quotients by a common number that would give us the most simplified whole number ratio (so, if we had gotten 1 and 1.5, we'd multiply both by 2, and the empirical formula would have subscripts 2 and 3).
To find the molecular formula (the actual formula of our compound), we use the molar mass of the compound, 78.1134 g/mol. The molar mass of our "empirical compound," CH, is 13.0186 g/mol. Since our empirical formula represents the most simplified molar ratio of the elements, the molar masses of our "empirical compound" and the actual compound should be multiples of one another. We divide 78.1134 g/mol by 13.0176 g/mol and obtain 6. The subscripts in our molecular formula are equal to the subscripts in our empirical formula multiplied by 6.
Thus, our molecular formula is C₆H₆.
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As mentioned before, all the questions here can be answered following the procedure used to answer the first question above. In any case, I've provided the empirical and molecular formulae for the remaining questions below for your reference.
2. Empirical formula: C₁₃H₁₂O; molecular formula: C₁₃H₁₂O
3. Empirical formula: CH; molecular formula: C₈H₈
4. Empirical formula: C₂HCl; molecular formula: C₆H₃Cl₃
5. Empirical formula: Cl₄K₂Pt; molecular formula: Cl₄K₂Pt
6. Empirical formula: C₂H₄Cl; molecular formula: C₄H₈Cl₂
CH4+2 O2-> CO2 + 2 H2O
You burned 15.0 grams of methane (CH4) in an excess of oxygen and formed 23.8 grams of water. What was your percent yield, rounded to 3 sig-figs?
C= 12.001 g/mol
H= 1.008 g/mol
O= 16g/mol
From the chemical equation it is clear that, one mole or 16 g of methane gas gives 2 moles or 36 g of water. Then, 15 g gives 33.7 g of water. The actual yield is 23.8 g. Then the percent yield is 70.6%.
What is percent yield of a reaction?Percent yield of a reaction is the ratio of its actual yield to the theoretical yield multiplied by 100. The theoretical yield is calculated from the balanced chemical equation of the reaction.
molar mass of methane gas = 16 g/mol
molar mass of water = 18 g/mol
16 g of methane gives 2 moles or 36 g of water. Then 15 g of methane will gives:
(15×36)/16 = 33.7g
The actual yield of water = 23.8 g
then,
percent yield = 23.8 g/33.7 g × 100 = 70.6%.
Therefore, the percent yield of water is 70.6%.
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Humans have the ability to change the characteristics, or traits, of organisms over time. What is this process called?
A. Selective breeding
B. Artificial selection
C. Gene Therapy
D. Both A and B
Answer:
gene therapy.
Calcium has the symbol Ca and its ions have a charge of +2. Chlorine has the symbol Cl and its ions have a charge of -1. In the ionic compound calcium chloride, how many chloride ions are there for each calcium ion?
Answer:
There are two chloride ions for each calcium ion
Explanation:
The compound has to have an overall neutral charge. Meaning that the positive charges from calcium have to be canceled out by the negative charges of chlorine.
If there are two chloride ions for each calcium ion, the charges would cancel themselves out (2 * -1 would cancel out with +2).
Q 20.17: In IR spectroscopy, a conjugated ketone will produce a C=O signal at a ___________________ wavenumber, compared with a non-conjugated ketone of similar structure.
Answer:
See explanation
Explanation:
Infrared spectroscopy is concerned with transitions between vibrational energy levels. Each infrared active vibration leads to a change in dipole moment.
A ketone compound contains the -C=O group whose signal normally occurs at about 1710 cm-1.
A conjugated ketone is one in which the -C=O group is attached to the -C=C group. This leads to delocalization and reduces the electron density of the C=O double bond, which weakens this bond hence lowering the stretching frequency of the -C=O bond from 1710 to about 1680cm-1.
Determine the mass of aluminum (Al) produced in the reaction if 30.00 grams of magnesium (Mg) was consumed with the equation given; 2 AlPO4(aq) + 3 Mg(s) = 2 Al(s) + 1 Mg3(PO4)2(aq)
Answer:
22.21 grams of aluminum (Al) was produced in the reaction if 30.00 grams of magnesium (Mg) was consumed.
Explanation:
The balanced reaction is:
2 AlPO₄ (aq) + 3 Mg (s) → 2 Al (s) + 1 Mg₃(PO₄)₂ (aq)
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
AlPO₄: 2 molesMg: 3 molesAl: 2 molesMg₃(PO₄)₂: 1 moleBeing the molar mass of each compound:
AlPO₄: 122 g/moleMg: 24.31 g/moleAl: 27 g/moleMg₃(PO₄)₂: 262.93 g/moleBy reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
AlPO₄: 2 moles* 122 g/mole= 244 gramsMg: 3 moles* 24.31 g/mole= 72.93 gramsAl: 2 moles* 27 g/mole= 54 gramsMg₃(PO₄)₂: 1 mole* 262.93 g/mole= 262.93 gramsYou can apply the following rule of three: if by stoichiometry 72.93 grams of Mg produces 54 grams of Al, 30 grams of Mg produces how much mass of Al?
[tex]mass of Al=\frac{30 grams of Mg*54 grams of Al}{72.93 grams of Mg}[/tex]
mass of Al= 22.21 grams
22.21 grams of aluminum (Al) was produced in the reaction if 30.00 grams of magnesium (Mg) was consumed.
How many moles of NH3 could you produce with 0.24 moles of H2 and excess nitrogen gas?
Answer:
[tex]0.16\; \rm mol[/tex].
Explanation:
[tex]\rm H_2[/tex] and [tex]\rm N_2[/tex] react to produce [tex]\rm NH_3[/tex] through the following reaction:
[tex]\rm 2\; N_2 + 3\; H_2 \to 2\; NH_3[/tex].
The ratio between the coefficients and [tex]\rm NH_3[/tex] and [tex]\rm H_2[/tex] is:
[tex]\displaystyle \frac{n({\rm NH_3})}{n({\rm H_2})} = \frac{2}{3}[/tex].
This coefficient ratio would be the ratio between the quantity of [tex]\rm NH_3[/tex] produced and the quantity of [tex]\rm H_2[/tex] consumed in this reaction only if [tex]\rm H_2\![/tex] is a limiting reactant.
The other reactant in this reaction, [tex]\rm N_2[/tex], is in excess. Hence, [tex]\rm H_2[/tex] would be the limiting reactant. Hence, the coefficient ratio could be used to find the quantity of [tex]\rm NH_3[/tex] produced in this reaction.
[tex]\begin{aligned}n({\rm NH_3}) &= \frac{n({\rm NH_3})}{n({\rm H_2})} \cdot n({\rm H_2}) \\ &= \frac{2}{3} \times 0.24\; \rm mol \\ &= 0.16\; \rm mol \end{aligned}[/tex].
Explain why it is necessary to use a mixture, alumina and cryolite, rather than just
alumina
Explanation:
The mixture of cryolite and aluminium oxide has a lower melting point than pure aluminium oxide. This means a lower amount of energy is required to establish effective conditions for electrolysis and thus makes it more cost effective.
Nitrogen monoxide + oxygen → nitrogen dioxide.
How do.i write that in skeleton equation
What is the formula unit for a compound made from Li and Cl? (5 points)
LiCl because the total negative charge on Cl is one.
LiCl because the total negative charge on Li is two.
Li2Cl because the total positive charge on Cl is one.
Li2Cl because the total positive charge on Li is two.
Answer:
LiCl because the total negative charge on Cl is one.
Explanation:
Lithium has a charge of 1+ and Chlorine has a charge of 1-.
There are two types of chemical compound one is covalent compound and other is ionic compound. LiCl because the total negative charge on Cl is one. The correct option is option A.
What is chemical Compound?
Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
Covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Ionic compounds are hard, these have higher melting and boiling point than the covalent compounds. Li act as cation Li⁺ and Cl act as Cl⁻. These two combine to form LiCl. LiCl is an ionic compound.
Therefore, LiCl because the total negative charge on Cl is one. The correct option is option A.
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An atom or bonded group of atoms with a positive or neqative charge
Answer:
Radical
Explanation:
Wait did I get your quiz right? Are you asking for the name? If so it's radical
As current flows through a system, what happens to the voltage available at each load?
Answer: voltage drops in each resistor ΔU= RI
Explanation: if lamps or other resistor which cause load are in series in
Electric circuit, current I passing circuit is same. Voltage decreases
In every resistor
How many moles are in 1.7 x 10^50 particles of Al?
2.8 × 10²⁶ moles Al
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
MolesAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
[Given] 1.7 × 10⁵⁰ particles Al
[Solve] moles Al
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
[DA] Set up: [tex]\displaystyle 1.7 \cdot 10^{50} \ particles \ Al(\frac{1 \ mol \ Al}{6.022 \cdot 10^{23} \ particles \ Al})[/tex][DA] Divide [Cancel out units]: [tex]\displaystyle 2.82298 \cdot 10^{26} \ moles \ Al[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
2.82298 × 10²⁶ moles Al ≈ 2.8 × 10²⁶ moles Al
how many moles are in 0.250 g of h20
Answer:
moles in 0.250 g of h20 is 1.349x10^-2
What mass of methane (CH4) gas occupies a volume of 0,462 L at 1atm and 273K
Explanation:
Since methane gas is at 1 atm and 273 K, it is at standard temperature and pressure(STP).
One mole of every gas occupies 22.4 dm^3 at STP, and vice versa. So,
22.4 dm^3 at STP of CH4=1 mol=12+4(1)=16 g
0.462 L(0.462 dm^3) at STP of CH4
=(16 g×0.462 dm^3)/22.4 dm^3
=0.33 g
which substances corrode copper?
the number of ___ in an atom tells you how many chemical bonds that atom can form
How many grams are in 2.45E24 formula units of Fp3BZ2? The molar mass of Fp3Bz2. is 97.05
g/mol.
Answer:
394.99g
Explanation:
The number of moles of a substance can be calculated by dividing the number of atoms of such substance by Avagadro's number (6.02 × 10^23)
n = nA ÷ 6.02 × 10^23
The number of atoms of Fp3BZ2 in this question is 2.45E24 formula units i.e. 2.45 × 10^24
n = 2.45 × 10^24 ÷ 6.02 × 10^23
n = 2.45/6.02 × 10^(24-23)
n = 0.407 × 10¹
n = 4.07moles
Using mole = mass/molar mass
Where; molar mass of Fp3Bz2. is 97.05
g/mol.
mass = molar mass × mole
mass = 97.05 × 4.07
mass = 394.99g
How is my drawing. Rate it on a scale of 1-10
Answer:
I rate it 10/10
Explanation:
I like it. :)
Answer:
I think 8.5 it looks cool
Need help with this chemistry problem
PLEASE HELP ME. REAL ANSWERS ONLY PLZ
Answer:
Please make it full I'm not seeing it
calcium + zinc nitrate ------->
a) zinc + calcium chloride
b) there will be no reaction
c) zinc + calcium nitrate
d) calcium + zinc nitrate
Answer:
c
Explanation:
there will be displacement reaction taking place
Answer:
there will be no reaction
Explanation:
there will be no reaction since calcium does not displace zinc
Energy changes form or is transferred through the action of forces. An example of kinetic energy changing to potential energy is?
A) a bolder sitting on a cliff.
B)a person running around a track.
C) a car being driven up a hill and being parked.
D) a rubber band being stretched and being broken.
Answer:
I think answer is option no. C
Living organisms contain a variety of specailsed cells name one example of a specialised cell in the body and state its function example : function :
Answer:
See the answer below
Explanation:
The cell represents the basic unit of life and any living organism.
One example of specialized cells in the body are the sex cells.
The sex cells are primarily concerned with reproduction and perpetuation of life. The cells undergo meiosis to produce haploid gametes. Male and female gametes then fuse together during fertilization to give rise to diploid zygotes which eventually give rise to new organisms.
what would be necessary to change a liquid to a gas
Answer:
latent heat, also called the heat of vaporization, is the amount of energy necessary to change a liquid to a vapour at constant temperature and pressure.
Explanation:
The question is~ Which is not a biomass energy source?
Answer:
I think its sun but I'm not sure
Where is the potential energy to run the plant?
A 3
B
4
С
1
D
2
Answer: C
Explanation:
your well wisher
What causes the periodic (recurring)
patterns seen in the periodic table?
Balance this chemical equation. A coefficient of "1" is understood. Choose option "blank" for the correct answer if the coefficient is "1."
Choose... H 2 O 2 → Choose... H 2 O + Choose... O 2
What is the temperature range for our planet? Why is this important?
Answer:
are temperature range for are planet is -129 ⁰F (-18⁰C) that's the minimum.
+136⁰F (+58⁰C) this is the maximum surface temperature
Explanation:
"the planet is not too close or too far away from the sun, earth's atmosphere also plays a vital role is regulating the temperature by providing a blanket of gases that not only protects us from excessive heating and harmful radiation from the sun, but also traps heat rising from earth's interior core, keeping us warm"- Space.com
50 g of ice, at 0 oC, is added to 500 g of water at 75 o What is the final temperature? Cice = 2.093 J/g-oC, cH2O = 4.186 J/g-oC.
Answer:
The final temperature of the mixture is 71.43 ⁰C
Explanation:
Given;
mass of ice, m₀ = 50 g
initial temperature of the ice, t₀ = 0 ⁰C
mass of water, m₁ = 500 g
initial temperature of water, t₁ = 75 ⁰C
specific heat capacity of ice, C₀ = 2.093 J/g⁰C
specific heat capacity of water, C₁ = 4.186 J/g⁰C
Let the final temperature of the mixture = T
The heat lost by the water = The heat gained by the ice
m₁c₁ (75 - T) = m₀c₀ (T - 0)
500 x 4.186 x (75 - T) = 50 x 2.093 x T
156975 - 2093T = 104.65T
156975 = 104.65T + 2093T
156975 = 2197.65T
T = 156975 / 2197.65
T = 71.43 ⁰C
Therefore, the final temperature of the mixture is 71.43 ⁰C