Answer: The empirical formula and the molecular formula of the hydrocarbon is [tex]C_2H_3[/tex] and [tex]C_4H_6[/tex] respectivley.
Explanation:
The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:
[tex]C_xH_y+O_2\rightarrow CO_2+H_2O[/tex]
where, 'x', 'y' are the subscripts of Carbon, hydrogen
We are given:
Mass of [tex]CO_2[/tex] = 12.74 g
Mass of [tex]H_2O[/tex]= 3.913 g
Molar mass of carbon dioxide = 44 g/mol
Molar mass of water = 18 g/mol
For calculating the mass of carbon:
In 44g of carbon dioxide, 12 g of carbon is contained.
So, in 12.74 g of carbon dioxide, =[tex]\frac{12}{44}\times 12.74=3.474g[/tex] of carbon will be contained.
For calculating the mass of hydrogen:
In 18g of water, 2 g of hydrogen is contained.
So, in 3.913 g of water, =[tex]\frac{2}{18}\times 3.913=0.435g[/tex] of hydrogen will be contained.
Mass of C = 3.474 g
Mass of H = 0.435 g
Step 1 : convert given masses into moles.
Moles of C =[tex] \frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{3.474g}{12g/mole}=0.289moles[/tex]
Moles of H=[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.435g}{1g/mole}=0.435moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C =[tex]\frac{0.289}{0.289}=1[/tex]
For H =[tex]\frac{0.435}{0.289}=1.5[/tex]
The ratio of C : H = 1: 1.5
The whole number ratio will be = 2: 3
Hence the empirical formula is [tex]C_2H_3[/tex].
The empirical weight of [tex]C_2H_3[/tex] = 2(12.01)+3(1.008)= 27.04 g.
The molecular weight = 54.09 g/mole
Now we have to calculate the molecular formula.
[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{54.09}{27.04}=2[/tex]
The molecular formula will be=[tex]2\times C_2H_3=C_4H_6[/tex]
name the following substances
KCl
FeCl2
CuSO4
Al2O3
Fe2O3
Potassium chloride
Iron (II) chloride
Copper (II) sulfate
Aluminum oxide
Iron (III) oxide
Remember to put roman numerals for the compounds where the metal has more than one possible oxidation state. For example, you see iron here with a +2 charge in one compound and then +3 charge in another. If the metal only has one possible oxidation state (like potassium and aluminum), you don't need a roman numeral.
Section I: Experimental Overview
Provide background information.
Include the hypothesis(es).
Summarize the procedures.
Section II: Data and Observations
Summarize the data you collected in the lab guide.
Include information from data tables.
Include any written observations that are relevant.
Section III: Analysis and Discussion
Discuss any important calculations or formulas used.
Identify key results, what the results indicate, and any trends in the data.
Include graphs (if constructed) that display trends in the data.
Provide possible reasons for any problems with the experiment, or unexpected data.
Section IV: Conclusions
Identify if the hypothesis(es) was (were) supported or refuted.
Provide logical reasoning based on data.
Explain how the experiment could be improved.
To help you write your lab report, you will first answer the questions listed below by reflecting on the experiment you have just completed. Then you will use the answers to these questions to write the lab report that you will turn into your teacher.
You can upload your completed report with the upload tool in formats such as , Microsoft Word, or PDF. Alternatively, your teacher may ask you to turn in a paper copy of your report or use a web-based writing tool.
Questions
Section I: Experimental Overview
What is the purpose of the lab, the importance of the topic, and the question you are trying to answer?
What is your hypothesis (or hypotheses) for this experiment?
What methods are you using to test this (or each) hypothesis?
Section II: Data and Observations
Locate the data and observations collected in your lab guide. What are the key results? How would you best summarize the data to relate your findings?
Do you have quantitative data (numerical results or calculations)? Do you have qualitative data (written observations and descriptions)? How can you organize this date for your report?
Section III: Analysis and Discussion
What do the key results indicate?
If you constructed graphs, what trends do they indicate in your data?
Answer:
If you constructed graphs, what trends do they indicate in your data?
Using standard heats of formation, calculate the standard enthalpy change for the following reaction.
2H2(g) + O2(g)
—>2H20(9)
Answer:
ΔH°r = -483.64 kJ
Explanation:
Let's consider the following balanced equation.
2 H₂(g) + O₂(g) ⇒ 2 H₂O(g)
We can calculate the standard enthalpy change of the reaction (ΔH°r) using the following expression.
ΔH°r = ∑ΔH°f(p) × np - ∑ΔH°f(r) × nr
where
ΔH°f: standard heat of formation
n: moles
p: products
r: reactants
ΔH°r = ΔH°f(H₂O(g)) × 2 mol - ΔH°f(H₂(g)) × 2 mol - ΔH°f(O₂(g)) × 1 mol
ΔH°r = (-241.82 kJ/mol) × 2 mol - 0 kJ/mol × 2 mol - 0 kJ/mol × 1 mol
ΔH°r = -483.64 kJ
A mixture of gaseous reactants is put into a cylinder, where a chemical reaction turns them into gaseous products. The cylinder has a piston that moves in or out, as necessary, to keep a constant pressure on the mixture of . The cylinder is also submerged in a large insulated water bath. (See sketch at right.) From previous experiments, this chemical reaction is known to release of energy. The position of the piston is monitored, and it is determined from this data that the system does of work on the piston during the reaction.
Answer:
It is exothermic in nature.
Explanation:
(1) The reaction is exothermic in nature because it releases heat energy.
(2) Yes, the temperature of the water go up as the reaction releases heat energy and the temperature cool down as the heat energy is completely removed from the water.
(3) The piston move in when the pressure in the cylinder decreases and the piston move out when increase of pressure occur.
(4) As the outside movement of piston occurs, so we can say that the gas mixture does work on its surroundings.
(5) The system released 244 kJ of energy, in which only 150 kJ went into the water, then the difference must be the work done by the system on its surroundings.
W = (244 - 150) kJ = 94 kJ
2 NaClO3→ 2 NaCl + 3 O2
How many moles of O2 are produced when 40g of NaCl are formed?
Answer:
75.6
Explanation:
Kidney stones generally form from the double displacement reaction of two salts that form an insoluble compound, a precipitate. (Read through the background for Week 1 for more information.) which of the following salts will participate in a double displacement reaction with Na3PO4 to form an insoluble compound(s): __________
Ca(NO3)2
(NH4)2SO4
NaCl
KNO3
Answer: [tex]Ca(NO_3)_2[/tex]
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
A double displacement reaction in which on e of the product is formed as a solid is called as precipitation reaction.
The balanced chemical equation for a precipitation reaction is:
[tex]2Na_3PO_4(aq)+3Ca(NO_3)_2(aq)\rightarrow Ca_3(PO_4)_2(s)+6NaNO_3(aq)[/tex]
The salt that should be participated in the double displacement reaction should form the insoluble compound(s) i.e. Ca(NO3)2.
What is a double displacement reaction?It is the one where the ions should be exchanged. The salts should be soluble in water that should be designated by symbol and can be insoluble in water also same in the solid form. The same should be presented by (s) when the chemical formulas are mentioned. Also, it is one of the product that should be created known as the precipitation reaction.
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For each of the following, predict the complete, balanced chemical equation for the reaction that occurs when they are mixed. Make sure to label the states!
1. HNO3 & NaOH
2. Sr(OH)2 & HI
Answer:
1. The balanced chemical reaction is:
[tex]HNO_3(aq)+NaOH(aq)\rightarrow NaNO_3(aq)+H_2O(l)[/tex]
2. The balanced chemical reaction is:
[tex]2HI(aq)+Sr(OH)_2(aq)\rightarrow SrI_2(aq)+2H_2O(l)[/tex]
Explanation:
Hello there!
In this case, according to the given chemical reactions, it is necessary to keep in mind the cations and anions are switched around as a result of the bonds rearrangement in these neutralization reactions; therefore, we can proceed as follows:
1. The balanced chemical reaction is:
[tex]HNO_3(aq)+NaOH(aq)\rightarrow NaNO_3(aq)+H_2O(l)[/tex]
Because all atoms are in the same amount at each side of the equation and the resulting salt is soluble.
2. The balanced chemical reaction is:
[tex]2HI(aq)+Sr(OH)_2(aq)\rightarrow SrI_2(aq)+2H_2O(l)[/tex]
Because all atoms are in the same amount at each side of the equation and the resulting salt is soluble.
Best regards!
how many grams are there in 1.30x10^24 atoms of silver?
Answer:
7
Explanation: i just guessed because i need some points
A scientist measures the standard enthalpy change for the following reaction to be 67.9 kJ:
Fe2O3(s) + 3 H2(
92Fe(s) + 3 H2O(9)
Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation
of H2O(g) is
kJ/mol.
Answer: The standard enthalpy of formation of [tex]H_2O(g)[/tex] is -252.1 kJ/mol.
Explanation:
The balanced chemical reaction is,
[tex]Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(g)[/tex]
The expression for enthalpy change is,
[tex]\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactantss}][/tex]
Putting the values we get :
[tex]\Delta H=[2\times H_f{Fe}+3\times H_f{H_2O}]-[1\times H_f{Fe_2O_3}+3\times H_f{H_2}][/tex]
[tex]67.9kJ=[(2\times 0)+(3\times H_f{H_2O})]-[(1\times -824.2kJ/mol)+3\times 0kJ/mol)][/tex]
[tex]H_f{H_2O}=-252.1kJ/mol[/tex]
Thus standard enthalpy of formation of [tex]H_2O(g)[/tex] is -252.1 kJ/mol.
14
Select the correct answer.
A compound has an empirical formula of CzHs. What is true about this empirical formula?
O A.
It models the structure of the compound.
OB
It shows the ratio of elements in the compound.
O c. It gives the mass of each atom in the compound.
OD.
It indicates the number of atoms in the compound.
OE.
It describes only this one compound.
Reset
Next
Answer:
answer B
It shows the ratio of elements in the compound
Explanation:
Chemical formulas tell you how many atoms of each element are in a compound, and empirical formulas tell you the simplest or most reduced ratio of elements in a compound. If a compound's chemical formula cannot be reduced any more, then the empirical formula is the same as the chemical formula.
The statement which is true about the empirical formula is: It shows the ratio of elements in the compound. The correct option is B.
Empirical formula:
The empirical formula of a compound represents the simplest, most reduced ratio of the elements present in the compound.
The empirical formula represents the simplest whole-number ratio of atoms of each element present in a compound.
It is determined by dividing the subscripts of the compound's molecular formula by their greatest common divisor, which simplifies the ratio to its simplest form.
In the given empirical formula CzHs, "z" and "s" represent the subscripts indicating the number of carbon and hydrogen atoms, respectively.
Thus, the correct option is B.
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A sample of gas initially has a volume of 2.25 L at 350 K and a pressure of 1.75 atm. What will be sample pressure if the volume is
changed to 1.00 L and the temperature to 750 K
O 3.75 atm
O 1.84 atm
O 3.94 atm
O 8.44 atm
O 0.119 atm
Answer:
8.44 atm
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 2.25 L
Initial temperature (T₁) = 350 K
Initial pressure (P₁) = 1.75 atm
Final volume (V₂) = 1 L
Final temperature (T₂) = 750 K
Final pressure (P₂) =?
The final pressure of the gas can be obtained as illustrated below:
P₁V₁/T₁ = P₂V₂/T₂
1.75 × 2.25 / 350 = P₂ × 1 / 750
3.9375 / 350 = P₂ / 750
Cross multiply
350 × P₂ = 3.9375 × 750
350 × P₂ = 2953.125
Divide both side by 350
P₂ = 2953.125 / 350
P₂ = 8.44 atm
Thus, the final pressure of the gas is 8.44 atm.
What two processes contributed oxygen to earth’s second atmosphere?
a.photosynthesis and volcanism
b.volcanism and weathering
c.weathering and rainfall
d.photosynthesis and photolysis
The two processes which contributed oxygen to earth’s second atmosphere are photosynthesis and photolysis.
What is photosynthesis?
It is defined as a process by which plants and other photosynthetic organisms convert the light energy in to chemical energy through the process of cellular respiration.
Some of the energy which is converted is stored in molecules of carbohydrates like sugar and starches which are made up of from carbon dioxide and water . Photosynthetic organisms which can perform photosynthesis are algae and cyanobacteria. Photosynthesis is largely responsible for producing and maintaining the content of oxygen in earth's atmosphere.
The process begins with proteins absorbing light energy which are called reaction centers and contain a green pigment which is called chlorophyll . In plants ,these pigments are present inside organelles called chloroplasts while in bacteria they are present in plasma membrane.
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What is the molar mass of a gas if 0.102 g of the gas occupies 0.070 L at STP? a. 32.6g / mol b. 28.2 g/mol c. 40.0g / mol d. 47.9 g/mol
Answer:
A. 32.6 g/mol
Explanation:
First convert the volume of gas to moles using the ratio 1 mol / 22.4 L at STP.
0.070 L • (1 mol / 22.4 L) = 0.00313 mol
Now divide the grams of gas by the moles of gas:
0.102 g / 0.00313 mol = 32.6 g/mol
Is carbon moving into the air moving out of the air or both
Answer:
Carbon is moving into the air
CaF2(s)⇄Ca2+(aq)+2F−(aq) Ksp=3.9×10−11
HF(aq)⇄H+(aq)+F−(aq) Kc=6.8×10−4
The dissolution of calcium fluoride is represented by the equilibrium system above at 25°C. The F− ion is produced when the weak acid HF dissociates. If solid calcium fluoride is added to equal volumes of the following solutions at 25°C, in which solution will the most calcium fluoride dissolve?
A) Pure distilled water
B) 1MHNO3(aq)
C) 1MNaOH(aq)
D) A saturated aqueous CaF2 solution
The solution in which the most calcium fluoride dissolves is 1M HNO3(aq).
Option (B) is correct.
What is Le Châtelier's principle?A system in equilibrium is subjected to change (change in concentration/pressure of reactants/products, temperature, etc.) according to Le Châtelier's principle.
To counterbalance the change and restore equilibrium, the System advances in a direction.
In solution, HNO is a strong acid that will dissociate fully to generate H+ and No3-.
This increasing concentration of H+ will cause the second equilibrium reaction in question to reverse direction, resulting in the production of additional HF.
As a result of the drop in F- concentration, the dissolution equilibrium process of Caf2 moves forward, dissolving more valid CaF2 to produce Ca2+ and F_ and thereby boosting Caf2 solubility.
Thus, HNO3 (B) is the correct option.
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Convert 0.809 mol AlCl3 to formula units AlCl3.
Answer:
133.340538.
Explanation:
The answer is 133.340538. We assume you are converting between grams AlCl3 and mole. You can view more details on each measurement unit: molecular weight of AlCl3 or mol This compound is also known as Aluminium Chloride. The SI base unit for amount of substance is the mole.
The force of gravity from Earth to Mars is___
a. less than the force of gravity from Mars to Earth.
b. equal to the force of gravity from Mars to Earth.
less than the force of gravity from mars to earth
What is the volume of a 5.00 molar solution containing 20 moles of 0.40 10.0L 0.010L
Answer:
Volume of solution = 4 liter
Explanation:
Given:
Molarity = 5 M
Number of moles = 20 moles
Find:
Volume of solution
Computation:
Moles of solute mixed per litre of solution is known as molarity. A 1 M sample is the one in which 1 molecule of solvent is soluble in one liter of solution volume.
M = Mol / L
5 = 20 / L
Volume of solution = 4 liter
In an aqueous solution at 25°C, if [H30+] = 3.3 * 10^4 M, then [OH-] is:
Answer:
[OH-] = 3.0 x 10^-19 M
Explanation:
[H3O+][OH-] = Kw
Kw = 1.0 x 10^-14
[H3O+][OH-] = 1.0 x 10^-14
[OH-] = 1.0 x 10^-14 / 3.3 x 10^4 = 3.0 x 10^-19
A transverse wave is observed to be moving along a lengthy rope. Adjacent crests are positioned 2.4 m apart. Exactly six crests are observed to move past a given point along the medium in 9.1 seconds. Determine the frequency of these waves
Answer:
f = 0.65 hz
Explanation:
Given that,
The distance between adjacent crests, wavelength = 2.4 m
6 crests are observed to move past a given point along the medium in 9.1 seconds.
We need to find the frequency of these waves.
We know that,
Frequency = no. of waves per second.
[tex]f=\dfrac{6}{9.1}\ Hz\\\\=0.65\ Hz[/tex]
So, the frequency of these waves is equal to 0.65 Hz.
can anyone help on this?
Answer:
26
Explanation:
What can happen to a rock when water flows through cracks or holes in the rock?
Answer:
it will crack because if the water inside of a rock freezes the water would start to expand and start stretching it causing it to break
Explanation:
What geologic process creates a stack?
a.river erosion
b.tectonic activity
c.wave erosion
d.glaciation
Answer:
c.wave erosion=>A stack or sea stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion.
Which of these hazmat products warnings or labels are allowed in your FC?
Please choose all that apply.
Fully Regulated Aerosol Placard
Fully Regulated Flammable
Liquid Placard
Fully Regulated Flammable Solid Placard
Lithium-Ion/Metal Battery label
Answer:
The following are the Hazmat products warnings that are allowed:
Fully Regulated Aerosol Placard
Fully Regulated Flammable
Fully Regulated Flammable Solid Placard
Lithium-Ion/Metal Battery label
Explanation:
Hazmat products are substances and materials that are dangerous and poses a risk to people when stored, handled or transported from one location to another at any given time.
Those products are meant to be handled with utmost care, and any carelessness on the individual in question could lead to harm. For example, regulated flammable liquid like kerosene needs utmost care when stored to avoid causing fire outbreak in the location where it is stored.
Why are weather front boundaries turbulent?
Answer:
Answer Below Hope Its Correct.
Explanation:
A weather front is a transition zone between two different air masses at the Earth's surface. Each air mass has unique temperature and humidity characteristics. Often there is turbulence at a front, which is the borderline where two different air masses come together. The turbulence can cause clouds and storms.
Instead of causing clouds and storms, some fronts just cause a change in temperature. However, some storm fronts start Earth's largest storms. Tropical waves are fronts that develop in the tropical Atlantic Ocean off the coast of Africa. These fronts can develop into tropical storms or hurricanes if conditions allow.
Fronts move across the Earth's surface over multiple days. The direction of movement is often guided by high winds, such as Jet Streams. Landforms like mountains can also change the path of a front.
There are four different types of weather fronts: cold fronts, warm fronts, stationary fronts, and occluded fronts.
Where do living organisms obtain energy for cell processes?
A. When bonds form during cell processes, energy is absorbed.
B. When bonds form during cell processes, energy is released.
C. When bonds in food are broken, energy is released.
Answer:
(C) when bonds in food are broken, energy is released
11. Which of the following elements CANNOT violate the octet rule?
a.
Nitrogen
b. Phosphorus
c. Sulfur
d. lodine
Answer:
I think it's Nitrogen is right answer
A liquid medicine is labeled as having 5% active ingredient, by volume. If
the dosage of the medicine is 50 mL, how much of the active ingredient is
to be ingested? *
Answer:
2.5 mL
Explanation:
Step 1: Given data
Concentration of the active ingredient (C): 5% v/vVolume of the medicine (V): 50 mLStep 2: Calculate the amount of the active ingredient in the medicine
The concentration of the active ingredient is 5% v/v, that is, there are 5 mL of the active ingredient per 100 mL of the medicine. The volume of the active ingredient is 50 mL of the medicine is:
50 mL Med × 5 mL AI/100 mL Med = 2.5 mL AI
Given [H3O+] = 3.06x10-10 M, find the [OH-].
Show your calculation for full credit
Answer:
3.27*(10^-5) M
Explanation:
For 25°C:
[H3O+] *[OH-] =(10^-14)-->
[OH-]=(10^-14)/[H3O+]-->
[OH-]=(10^-14)/(3.06*10^-10)-->
[OH-]=3.27*(10^-5) M
Can somebody please help me!!!
Answer:
energy
Explanation:
Energy is used to do work or produce change. Friction and velocity do not do this.
