Answer:
7.14%
Explanation:
From the question,
percentage by mass hydrogen in C₄H₈O₃ (h) = mass of hydrogen present in C₄H₈O₃(m)/molar mass of C₄H₈O₃ (m')
h = (m'/m)×100..................... Equation 1
Given: m' = (14×4)+(1×8)+(16×3) = 56+8+48 = 112 g, m = (1×8) = 8 g
Substitute these values into equation 1
h = (8/112)×100
h = 7.14%.
Hence the percentage of hydrogen in 70 g of C₄H₈O₃ is 7.14%
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.
Due today:
How do you think the birds "predicted" Hurricanes
how many grams are there in 1.30x10^24 atoms of silver?
Answer:
7
Explanation: i just guessed because i need some points
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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please write the equation and help me solve. please no links
Answer: The molality of solution is 1.2 mole/kg
Explanation:
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.
[tex]Molality=\frac{n}{W_s}[/tex]
where,
n = moles of solute
[tex]W_s[/tex] = weight of solvent in kg
Given : 10 g of glycerol is present in 100 g of solution
moles of glycerol = [tex]\frac{\text {given mass}}{\text {molar mass}}=\frac{10g}{92g/mol}=0.108mol[/tex]
mass of water (solvent )= (100-10) = 90 g = 0.09 kg
Now put all the given values in the formula of molality, we get
[tex]Molality=\frac{0.108mol}{0.09kg}=1.2mole/kg[/tex]
Therefore, the molality of solution is 1.2 mole/kg
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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can anyone help on this?
Answer:
26
Explanation:
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?
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 chemist prepares a solution of silver(I) nitrate AgNO3 by measuring out 62.3μmol of silver(I) nitrate into a 50.mL volumetric flask and filling the flask to the mark with water.
Calculate the concentration in /molL of the chemist's silver(I) nitrate solution. Be sure your answer has the correct number of significant digit
*please write the answer without any files disturbance*
Answer:
0.0012 mol/L.
Explanation:
From the question given above, the following data were obtained:
Number of mole of AgNO₃ = 62.3 μmol
Volume = 50 mL
Molarity of AgNO₃ =?
Next, we shall convert 62.3 μmol to mole. This can be obtained as follow as follow:
1 μmol = 10¯⁶ mole
Therefore,
62.3 μmol = 62.3 × 10¯⁶
62.3 μmol = 62.3×10¯⁶ mole
Next, we shall convert 50 mL to L. This can be obtained as follow:
1000 mL = 1 L
Therefore,
50 mL = 50 mL × 1 L / 1000 mL
50 mL = 0.05 L
Finally, we shall determine the concentration of AgNO₃ in mol/L as follow:
Number of mole of AgNO₃ = 62.3×10¯⁶ mole
Volume = 0.05 L
Molarity of AgNO₃ =?
Molarity = mole /Volume
Molarity of AgNO₃ = 62.3×10¯⁶ / 0.05
Molarity of AgNO₃ = 0.0012 mol/L
Thus, the concentration of AgNO₃ is 0.0012 mol/L
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
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.
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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Can somebody please help me!!!
Answer:
energy
Explanation:
Energy is used to do work or produce change. Friction and velocity do not do this.
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
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
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
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
Which statement is true about fossils?
a.Only the remains of animals, and not plant, can be made into a fossil.
b.To officially be a fossil, the remains of an entire organism must be found.
c.The remains of an organism that lived 500 years ago is called a fossil.
d.A fossil is any trace of prehistoric life.
Answer:
d, the remains of an organism have to be 10,000 years old to be classified as a fossile:)
Answer:
(d)
Explanation:took the quiz
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!
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.
2 NaClO3→ 2 NaCl + 3 O2
How many moles of O2 are produced when 40g of NaCl are formed?
Answer:
75.6
Explanation:
Can somebody please help me!!!
Answer:
javier applied force how this helps
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.
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:
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
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
Is carbon moving into the air moving out of the air or both
Answer:
Carbon is moving into the air
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.