We already know that number of moles is 0.0025 mol.
So if we know the volume of the gas at STP and the number of moles we can get the mass of the gas.
V = 0.056 L
1 mol = 22.4 L
Molar mass of He = 4.0026 g/mol
So to calculate the weight we need number of moles and molar mass.
weight = 0.0025 mol x 4.0026 g/mol
= 0.01 g
If the density of an ether was 0.727g/mL and the mass 17.7 grams, what is the volume?Report the answer in (mL) to three significant figures and also include the correct unit
Remembering the formula of density, we can clear the volume and replace the given data in the new formula:
[tex]\begin{gathered} \text{density}=\frac{mass}{volume}, \\ \text{volume}=\frac{mass}{density}. \end{gathered}[/tex]Our data is: for mass is 17.7 grams (g) and for density is 0.727 g/mL:
[tex]\text{volume}=\frac{17.7\text{ g}}{0.727\text{ }\frac{g}{mL}}=24.347mL=24.3mL.[/tex]The volume of the ether is 24.3 mL of 17.7g and 0.727 g/mL.
Oxygen and oxygen-containing compounds are involved in many different reactions. which balanced equation represents a reaction that involves 14 atoms of oxygen
Answer: 2C2H6+7O2→4CO2+6H2O
Explanation:
Answer:2C2H6+7O2→4CO2+6H2O
Explanation:
Bromination of isobutane is a two‑step reaction. Step 1 reaction is: a coumpound with a central carbon atom with three single bonded C H 3 groups and one single bonded hydrogen plus radical bromine react to form a compound with a central carbon atom with a single electron and three single bonded C H 3 groups plus bromine with a single bonded hydrogen atom. Step 2 reaction is: a compound with a central carbon atom with a single electron and three single bonded C H 3 groups plus bromine single bonded to bromine react to form a coumpound with a central carbon atom with three single bonded C H 3 groups and one single bonded bromine plus radical bromine. The overall reaction is: a coumpound with a central carbon atom with three single bonded C H 3 groups and one single bonded hydrogen plus bromine single bonded to bromine react to form a coumpound with a central carbon atom with three single bonded C H 3 groups and one single bonded bromine plus bromine with a single bonded hydrogen atom. Using the table of bond dissociation energies for A−B⟶A+B, calculate the enthalpy of each step and the enthalpy of the overall reaction.
Bromination of isobutane is a two‑step reaction.
The enthalpy of each step : step 1: ΔH = 34 kJ/mol. step 2 : ΔH = -99 kJ/mol enthalpy of the overall reaction , ΔH = 65 kJ/mol.
Bond dissociation energy :
H - H = 436 kJ/mol
H - Br = 366 kJ/mol
Br - Br = 193 kJ/mol
(CH₃)₃C - H = 400 kJ/mol
(CH₃)₃C - Br = 292 kJ/mol
Step 1 : (CH₃)₃C - H + Br ------> (CH₃)₃C° + H - Br
ΔH = ∑ Bond broken - ∑ Bond form
ΔH = 400 kJ/mol - 366 kJ/mol
ΔH = 34 kJ/mol
Step 2: (CH₃)₃C° + Br - Br ----> (CH₃)₃ - Br + Br
ΔH = ∑ Bond broken - ∑ Bond form
ΔH = 193 - 292
ΔH = - 99 kJ/mol
overall reaction :
(CH₃)₃ - H + Br - Br ----> (CH₃)₃ - Br + H- Br
ΔH = ( 400 + 193 ) - ( 292 + 366 )
ΔH = 593 - 658
ΔH = - 65 kJ/mol
Thus, Bromination of isobutane is a two‑step reaction.
The enthalpy of each step : step 1: ΔH = 34 kJ/mol. step 2 : ΔH = -99 kJ/mol enthalpy of the overall reaction , ΔH = 65 kJ/mol.
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Calculate the number of moles of carbon dioxide gas in this fire extinguisher. Gas type CO2 temperature: 212 K pressure: 4.55 atm Volume: 3.5L
Answer
0.9154 mol CO₂
Procedure
To solve this question you will need to use the ideal gas law
PV=nRT
Data
P=4.55 atm
V= 3.5 L
T= 212 K
R=0.082057 L⋅atm⋅K⁻¹⋅mol⁻¹
Solve for n
[tex]n=\frac{PV}{RT}=\frac{4.55\text{ atm }3.5\text{L mol }\degree\text{K}}{0.082057\text{ L.atm }212\degree\text{K}}=0.9154\text{ mol }[/tex]b) Assuming a reaction starts with 1 mole of octane, which burns at 220°C, and is at a pressure of 1 atm, what volume will the products occupy upon reaction completion?
Answer
40.48 liters
Explanation
Given: that:
n = mole = 1 mol
P = Pressure = 1 atm
T = Temperature = 220 °C = (220 + 273K) = 493 K
What to find:
The volume of the product.
Step-by-step solution:
The volume, V of the product can be calculated using the ideal gas equation:
PV = nRT
Putting the values of the parameters and molar gas constant, R = 0.0821 liter·atm/mol·K into the formula, we have:
[tex]\begin{gathered} V=\frac{nRT}{P}=\frac{1\text{ }mol\times0.0821\text{ }L.atm\text{/}mol.K\times493\text{ }K}{1\text{ }atm}=40.48\text{ }L \\ \end{gathered}[/tex]Thus, the volume of the product, upon reaction completion, will occupy 40.48 liters.
Classify the following amine as 1°, 2°, 3° or 4°(primary, secondary, tertiary, quaternary).CH3NH2A. primaryB. secondaryC. tertiaryD. quarternary
Explanation:
The degree of amines is determined by the number of carbons attached to the nitrogen.
According to the given picture, the answer is A.
Answer:
The answer is A.
midterm 3 In an effort to stretch already thin educational budgets, a county’s school cut home economics from their offered programs. Fast forward to 10 years down the road, which statement shows the MOST likely consequence of that choice? A. The county now has a generation of young adults who eat mostly fast food and take out. B. The county has a higher rate of college graduates and the median income has risen. C. The county has seen little to no change that can be traced back to the decision to cut the program. D. The county now has a generation of young adults who are opening new bars, breweries, and restaurants. wellness & nutrition
In an effort to stretch already thin educational budgets, a county’s school cut home economics from their offered programs fast forward to 10 years down the road then the county has a higher rate of college graduates and the median income has risen
Home economics be thought in the school again because student all over the world can be empowered by home economics programs by learning essential life skills that, occasionally, cannot be gained from textbooks or parents
And most significantly the knowledge and ability acquire on the home economic class give every student the confidence and positive reinforcement they require
Due to fact that it cover important concepts related to the family house, clothes, and food, this subject aids society in advancing human growth
Human advancement is essential to the development of society and also building essential life skills
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12. What are the 2 types of stability and how do they relate to the parts of the atom?
An atom is stable when its total charge is equal to 0 (zero).
There are 2 situacions that can make an atom not stable (or its total charge is not zero):
1. One situation is that the atom has excess of negative charge. In this case, the atom is stabilized by transferring valence electrons to another atom.
2. Another situation is that the atom has excess of positive charge. In this case, the atom is stabilized by obtaining electrons from another atom.
In both cases, the parts of the atom related to the stable state are the electrons.
In an experiment, hydrochloric acid reacted with different volumes of sodium thiosulfate in water. A yellow precipitate was formed during the reaction. A cross drawn at the base of each flask became gradually invisible due the formation of this yellow precipitate. The time taken for the cross to become invisible was recorded. A partial record of the experiment is shown.Experimental RecordFlaskVolume ofHClVolume ofSodium ThiosulfateVolume ofWaterTime110 mL10 mL40 mL14 seconds210 mL20 mL30 mL310 mL30 mL20 mL410 mL40 mL10 mLBased on your knowledge of factors that affect the rates of chemical reactions, predict the trend in the last column of the experimental record. Use complete sentences to explain the trend you predicted. You do not have to determine exact values for time; just describe the trend you would expect (increase or decrease) and why it occurs.
Answer
Decrease
Explanation
In the last column, the time it will take for the reaction to complete with decrease, meaning the rate of reaction will increase, this is because the reactant concentration was increased. Increasing the concentration of one or more reactants will often increase the rate of reaction. Because a higher concentration will lead to more collisions of that reactant at a specific time.
Iodine-131 has a half-life of 8 days. If you start with a sample of 150 grams, how much of the original isotope will remain after 30 days?A. 144 gramsB. 150 gramsC. 11 gramsD. 8 grams
The first step is to remember the equation for radioactive disintegration:
[tex]M(t)=\text{ M}_{0\text{ }}*\text{ }e^{\frac{-t\text{ * ln 2}}{T}}[/tex]Where M(t) is the mass of the atom at any time t, Mo is the initial mass of the element, and T is the half-life time.
In this case, we have to calculate M(t), which is the remaining mass of the radioactive element. We have all the data from the right part of the equation (initial mass Mo, the time t at we want to calculate the remaining mass, and the half-life T of the element):
[tex]\begin{gathered} M(8)=\text{ 150 g * }e^{\frac{-30\text{ d }*\text{ }ln\text{ 2}}{8\text{ d}}\text{ }} \\ M(8)=\text{ 11.1488 g} \end{gathered}[/tex]Then, the answer is that the remaining mass of iodine-131 is C. 11 g approx
How do I calculate each of these?- Fractional uncertainty in mass of liquid sample - Fractional uncertainty in volume of liquid sample - Fractional uncertainty in density of liquid sample - Uncertainty in density of liquid sample
Fractional uncertainty is found by dividing the absolute uncertainty by the quantity itself. It is always the same for every measure: mass, volume, density, etc.
For example, if we have this measure 7.5+-0.1kg. The fractional uncertainty is:
[tex]\frac{0.1}{7.5}=0.013[/tex]Which of the following are spectator ions in the reaction shown below? Select all that apply.
In this question, we have to find which ions are classified as spectator ions. The definition of spectator ions is the ones that will not participate directly in any change in the reaction.
In a reaction we usually have 2 main changes for the ions, they can change their oxidation number, in a reaction called redox reaction. They can also change their physical state, going from aqueous to solid.
The spectator ions will not have their oxidation number changed and they will not change their physical state.
The 2 ions that can be classified as spectator ions are Na+ and NO3-
Answer: son Na+ y NO3-
Explanation:
7.Write separate, balanced equations for the following double displacement neutralization reactionsa.Hydrochloric acid and sodium hydroxideb.Acetic acid and sodium hydroxide.
a)
Hydrochloric acid: HCl
Sodium hydroxide: NaOH
In the neutralization, an acid and a base react to neutralize the H⁺ and OH⁻, forming water.
In a displacement reaction, an atom in one of the components is displaced to another component in the reaction.
In the case of HCl and NaOH, we can see this as a double displacement, where H⁺ from HCl is exchanged by the Na⁺ of the NaOH, forming NaCl and H₂O:
[tex]HCl+NaOH\to NaCl+H_2O[/tex]b)
Acetic acid: CH₃COOH
Sodium hydrocide: NaOH
In this case, the NaOH is the same. the Aceitc acid dissociates in the following way:
[tex]CH_3COOH\to CH_3COO^-+H^+_{}[/tex]So, we just need to visualize the CH₃COO⁻ as the Cl⁻ of item a.
That is, we will have the reaction exchanging H⁺ and Na
A student stops a titration BEFORE theequivalence point is reached. If NaOH isbeing added to an unknown acid, HA, whations are present in the clear solution in theflask?A. H+, A-, Na+, OH-B. A-, Na+, OH-C. A-, Na+ and H+
Answer
ions are present in the clear solution in the flask, if NaOH is being added to an unknown acid, HA, before equivalence are:
. A⁻, Na⁺ and H⁺
How many grams of Iron are produced if 0.576 moles of Carbon dioxide are produced when Fe3O4 react with CO to form Fe and CO₂?
The mass of Iron produced by the reaction of given reactants will be 64.3 grams.
The balanced reaction is given as,
Fe₂O₃ + 3CO= 2Fe + 3CO₂
According to the chemical equation, 3 moles of carbon monoxide, CO, will react with 1mole of ferric oxide, Fe₂O₃, and produce 3 moles of carbon dioxide, CO₂
Now, we are given moles of carbon monoxide and asked for moles of Iron. This means that we will have to convert the aforementioned mole ratio that exists between carbon monoxide and carbon dioxide to a gram ratio.
If one mole of Iron has the mass of 55.845 g and one mole of carbon dioxide has a mass of 44.01 g, it follows that reaction produces
44.01g of carbon dioxide for the every 55.845 g of Iron.
So for 1 moles of carbon dioxide the mass will be 44.01 g
For 3 moles it is 3× 44.01 =132.03 gram
1 mole carbon dioxide has 55.845 g iron
0.576 moles has 55.845×0.576
44.01×3 g of carbon dioxide = 132.03 g
55.845×2 g of Iron = 111.69 g
So in 0.576 moles it will get 111.69×0.576
=64.3 grams of Iron are produced.
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I just need a clarification please for me I see they’re synthesis I want to be clear P4 + 6 H2 = 4 PH32 H2 + O2 = 2 H2O
In a synthesis reaction, two or more reagents react to form a new product. In decomposition reactions, a single reagent is separated into two or more new products.
According to the given equations:
Phosphorus and hydrogen react to form a new product which is phosphane.
It means that the first is a synthesis reaction.
Hydrogen and oxygen react to form a new product which is water.
It means that the second is also a synthesis reaction.
Energy is absorbed when an electron changes from principal energy level3 to 53 to 22 to 14 to 2
Answer:
[tex]3\text{ to 5}[/tex]Explanation:
When an electron moves from one energy level to another, energy is either absorbed or released
When an electron moves from a lower to a higher energy level, energy is absorbed. When an electron moves from a higher level to a lower level, energy is released
Since the electron moves from a lower level 3 to a higher level 5, emergy is absorbed
Thus, movement from 3 to 5 is the answer
Which of the following statements is FALSE? In its interaction with hemoglobin, oxygen is:
bound at the 6th coordination position of the Fe(II) ion in the heme.
a ligand.
homoallosteric effector.
a prosthetic group.
reversibly bound.
The statement in its interaction with hemoglobin, oxygen is a prosthetic group is False (Option 4).
What is the hemoglobin protein of the red blood cells?The hemoglobin protein of the red blood cells is a protein that binds to oxygen in order to transport this reactant of cellular respiration to all cells of the body.
Therefore, with this data, we can see that the hemoglobin protein of the red blood cells is required to bind oxygen which does not act as a prosthetic group and is a reactant of cellular respiration.
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Question 4 of 25aFor a bond to be covalent, the electronegativity difference between the atomsmust be:OA. zero.B. less than 1.7.OC. less than 0.5.D. over 2.
Answer:
B. Less than 1.7.
Explanation:
A covalent bond can be polar o non polar, but if the electronegativity difference between the atoms is less than 1.7 will be covalent polar and it will be covalent nonpolar if it is less that 0.5.
Which of the following describes how difficult it is to remove a valence electron from an atom of a particular element?
A: Electron Affinity
B: Ionization energy
C: Atomic Radius
D: Electronegativity
The term that describes how difficult it is to remove a valence electron from an atom of a particular element is electron affinity (option A).
What is electron affinity?Electron affinity is the energy released when an electron is attached to an atom or molecule; used as a measure of its ability to form an anion.
It becomes harder to remove an electron when an atom has a net positive charge because the attraction that the nuclear charge exerts per electron gets larger.
It takes a large amount of energy to remove electrons from an element with high electron affinity, hence, electron affinity determines how difficult it is to remove a valence electron from an atom.
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A block of al with a density of 2.7/ml has a mass of 549 g. what's the volume. ( show steps)
Explanation:
We are given: density of Al = 2.7g/mL
: mass of Al = 549g
[tex]\begin{gathered} \rho\text{ = }\frac{m}{V} \\ \\ \therefore\text{ V =}\frac{m}{\rho} \\ \\ \text{ =}\frac{549}{2.7} \\ \\ \text{ = 203.33mL} \end{gathered}[/tex]Answer:
The volume is 203.33mL
This number: 4.188x10^22 particles —-1cm ^3 x particles —-14.374cm^3 is about is about to number of silicon atoms this number: 6.20x10^23 particles is about the expected number of particles the silicon cube what are the differences of the two numbers ?
We are given two volume values, each volume has a certain number of molecules. The second number 6.20 x10^23 corresponds to the avogadro number and is equivalent to one mole of silicon. The first number does not make a molecule, so it must be only a fraction of the molecule of silicon being measured.
That will be the diference between the two number. 6.20 x10^23 is equivalent to one molecule while 4.188x10^22 is not.
ObjectiveYou will write a report on the states ofmatter, answering the question:How do water molecules change as theirstate of matter changes from solid, to liquid,to gas?MaterialsParagraph graphic organizerRubricThe Changing Water MoleculeReportHow do water molecules change as theirstate of matter changes? You will explorethese changes as you write your report onthe changing molecules.Hydrogen and oxygen bond together to formwater molecules. Water's state of matter willchange depending on how these moleculesare arranged. You have been learning aboutthe three states of matter - solid, liquid, andgas. Use this knowledge to write a report inresponse to this question:How do water molecules change as theirstate of matter changes from solid, toliquid, to gas?Your report should include an introduction, aparagraph for each state of matter..
Topic sentence:
All matter is composed of atoms that are in constant motion, three types of motion can be identified translation, rotation, and vibration. These particles are so small that they cannot be observed even with the smallest microscope, but they are so important that depending on their motion and interaction with other particles will be their state and how we see them at the macroscopic level. The greater the movement of the molecules the greater the disorder, so we can distinguish three states of matter presented from greater to lesser disorder: gas, liquid and solid.
Gas:
The motion in gases presents the three types of movement: translation, rotation, and vibration, and is the most intense. In the case of gases, the particles are quite far apart compared to their size. The approximate average distance between particles, under normal conditions, is ten times the particle size. In gases the particles do not occupy fixed positions, they are disordered and move randomly vibrating, rotating, and moving in all directions.
Liquid:
Liquids also exhibit all three types of motion (translation, rotation, and vibration) but with less intensity than in gases. In liquids, the particles do not occupy fixed They are disordered, although less so than in gases, and move randomly, as in gases, but with less intensity.
Solid:
The cohesive forces in solids are strong, much greater than in liquids, which are weak, and practically non-existent in gases. In solids, the particles occupy fixed positions, are ordered, and have no translational or rotational motion, only vibration.
Concluding sentence:
For all states of matter, the pressure and temperature involved will affect the order of the molecules making it possible to pass from one state to another by changing these variables.
Calculate the concentration of the solution in mass percent 178mg C6H12O6 in 4.91g H2O
In this question, we need to calculate the percent mass concentration of one solute in one solvent, and we have:
178mg of C6H12O6
4.91g of H2O
To calculate the mass percent concentration, we can use the following formula:
%mass = (mass of solute/mass of solution)*100
But first, we need to have both compounds in the same unit, so 178mg will be equal to 0.178g
Now we add these values into the formula:
%mass = (0.178/5.088) * 100
mass = 3.50%
The 5.088 is because 4.91 + 0.178
Calculate percent volume/volume of a solution that contains 80 ml of methanol and 230 ml of water?
25.81%
Explanations:The formula for calculating the percent volume/volume of a solution is given as:
[tex]\%v\text{/v}.=\frac{volume\text{ of solute}}{volume\text{ of solution}}\times100[/tex]Given the following parameters
volume of solute (methanol) = 80mL
volume of solution = volume of water + methanol
volume of solution = 80mL + 230mL = 310mL
Determine the required percent v/v
[tex]\begin{gathered} \%v\text{/}v=\frac{80mL}{310mL}\times100 \\ \%v\text{/}v=\frac{800}{31} \\ \%v\text{/}v=25.81\% \end{gathered}[/tex]Hence the percent volume/volume of a solution that contains 80 ml of methanol and 230 ml of water is 25.81%
Calculate the moles of HCI needed to react completely with 8.25 moles of zinc. I picked C but I’m not sure if I’m correct
Answer:
D. 16.5 moles
Explanation:
From the balanced reaction we know that 1 mole of Zn reacts with 2 moles of HCl.
We can calculate the moles of HCl needed to react completely with 8.25 moles of zinc, using the stoichiometry of the reaction and a mathematical rule of three:
[tex]\begin{gathered} 1moleZn-2molesHCl \\ 8.25molesZn-x=\frac{8.25molesZn*2molesHCl}{1moleZn} \\ x=16.5molesHCl \end{gathered}[/tex]So, 16.5 moles of HCl are needed.
Aqueous solutions of all the salts are neutral in nature i.e. neither acidic nor basicin nature.T or F
In nature it is possible to find aqueous solutions of salts in both basic and acidic forms, for the basic salts, which can also be called Alkali salts, we have a few, for example, Sodium carbonate, Sodium sulfide, Sodium hydroxide. For the acidic salts we can have NaHSO4, Sodium bisulfate. Therefore this is a false statement.
The best example of a solution among the following is ______.A. chalk powder in waterB. muddy waterC. table salt (sodium chloride) in waterD. oil in water
Answer
C. table salt (sodium chloride) in water
Explanation
Sodium chloride dissolves in water forming a solution
(07.05 HC)In an experiment, sulfuric acid reacted with different volumes of sodium thiosulfate in water. A yellow precipitate was formed during thereaction. A cross drawn at the base of each flask became gradually invisible due the formation of this yellow precipitate. The time taken for thecross to become invisible was recorded. A partial record of the experiment is shown.Experimental RecordFlask Volume of Volume of Volume of TimeH2SO4 Sodium Thiosulfate Water5 mL 50 mL10 mL 119 seconds5 mL 40 ml10 mL3 5 ml 30 ml120 mL4 15 ml 120 mL30 mLBased on your knowledge of factors that affect the rates of chemical reactions, predict the trend in the last column of the experimental record.Use complete sentences to explain the trend you predicted. You do not have to determine exact values for time; just describe the trend youwould expect (increase or decrease) and why it occurs.
The rate of the reaction usually depends on the concentration of the reactants. We have to reactants in this reaction, sulfuric acid and sodium thiosulfate. Let's look at the values that were recorded.
The volume of sulfuric acid that is added is constant, but the volume of sodium thiosulfate is not. It decreases and the volume of water increases, so we are diluting the sodium thiosulfate. The concentration of one reactant is decreasing. So the rate of the reaction is also decreasing. Then the time that it takes for the cross to become invisible should increase.
Answer: the time should increase.
Part III: Percent Yield1. If the reaction of 80 grams of Pb(NO3)2 produces 21.3 grams of NO2, what is thepercent yield?2Pb(NO3)2 → 2PbO + 4NO₂ +0₂2I
Explanation:
We determine the mass of NO2 from the mass of Pb(NO3)2:
m is the mass, M is the molar mass
[tex]\begin{gathered} m(NO2)\text{ = }\frac{m(Pb(NO3)2)}{M(Pb(NO3)2)}\text{ }\times\text{ }\frac{mol\text{ \lparen NO2\rparen}}{mol(Pb(NO3)2)}\text{ }\times\text{ M\lparen NO2\rparen} \\ \\ \text{ =}\frac{80}{331.2}\text{ }\times\frac{4}{2}\text{ }\times\text{ 46.0055} \\ \\ \text{ = 22.22g} \end{gathered}[/tex]Percent yield:
[tex]\begin{gathered} percent\text{ yield = }\frac{Actual\text{ yield}}{Theoretical\text{ yield}} \\ \\ \text{ =}\frac{21.3}{22.22} \\ \\ \text{ = 0.9586 }\times\text{ 100} \\ \\ \text{ = 95.86\%} \end{gathered}[/tex]Answer:
Percent yield = 95.86%