Answer:
two bonding and two unshared pair of electrons.Explanation:
Chlorite anion, ClO₂⁻ has one atom of chlorine and two atoms of oxygen.
Chlorine atom has 7 valence electrons (group 17 of the periodic table) and oxygen has 6 valence electrons (group 16 of the periodic table).
Thus, in total the anion has 7 + 6×2 electrons, plus an additional electron indicated by the negative charge of the anion: 7 + 12 + 1 = 20 valence electrons, that must be distributed among the three atoms.
Being chlorine the most electronegative atom, you place it in the center. surrounded by the two oxygen atoms.
Thus, so far:
O Cl O (pending to place the valence electrons.
You can put two electrons between each chlorine and oxygen atoms to form the bonds:
O : Cl : O
Also, complete the octets:
. . . . . .
: O : Cl : O :
. . . . . .
That structure works because:
there are 20 electronsevery atom has 8 valence electronsBut you need to calculate the formal charges on each atom:
For chlorine:
7 valence electrons - 4 nonbonding valence electrons - 4/2 bonding electrons = 7 - 4 - 2 = + 1.For each oxygen:
6 valence electrons - 6 nonbonding valence electrons - 2/2 bonding electrons = 6 - 6 - 1 = -1The total charge of the anion is +1 -1 - 1 = -1.
And the complete structure with the charge is:
. . . . . .
[ : O : Cl : O : ] ⁻
. . . . . .
The square bracketts comprise the entire anion and the negative charge is for the entire structure.
In this structure, the central atom (Cl) is surrounded by two bonding and two unshared pairs of electrons. (this is the answer to the question).
There is another structure which minimizes the formal charge, which will be preferred. It is by making a double bond between chlorine and one of the oxygen atoms, by moving two of the atoms beside one chlorine.
That structure is:
. . . . . .
: O : Cl :: O
. . . . . .
There you have 20 valence electrons and complete octets too, but the formal charges are:
Chlorine:
7valence electrons - 4 nonbonding electrons - 6/2 bonding electrons = 7 - 4 - 3 = 0The oxygen on the left is equal to the previous structure, thus - 1 forma charge.
The oxygen on the right:
6 valence electrons - 4 nonbonding electrons - 4/2 bonding electrons = 6 - 4 - 2 = 0Hence, this las structure minimizes the formal charges and is preferred.
This is:
. . . . . .
: O : Cl :: O
. . . . . .
But you must add the negative charge which belongs to the complete anion:
. . . . . .
[ : O : Cl :: O ] ⁻
. . . . . .
The square brackets comprise the entire anion and the negative charge is for it.
Hence, in this other structue the central atom, chlorine, is surrounded by six bonding electrons and four nonbonding electrons.
How many elements are in the following equation?
CH3COCH3
Answer:
3
Explanation:
Answer:
3
Explanation:
the 3 elements are carbon hydrogen and oxygen
Which element in period 3 has both metallic and non metalik properties
Answer:
Si is the answer I hope this help
An ionic precipitation reaction takes place when aqueous solutions of potassium phosphate and aluminum nitrate are combined in a beaker.
K3PO4(aq) + Al(NO3)3(aq) →
i. Predict the products and write a balanced chemical equation for the reaction,
including state symbols.
K3PO4(aq) + Al(NO3)3(aq) →
ii. Write the complete balanced ionic equation, including state symbols.
iii. Write the complete balanced net ionic equation, including state symbols.
Answer:
I hope you can get a good answer
Explanation:
What class is this for?
A 9.80 L container holds a mixture of two gases at 55 ° C. The partial pressures of gas A and gas B, respectively, are 0.298 atm and 0.589 atm. If 0.130 mol of a third gas is added with no change in volume or temperature, what will the total pressure become?
Answer:
1.24 atm is the new pressure
Explanation:
We may solve this question with the Ideal Gases Law that must be used, twice. → P . V = n . R . T
Total pressure = Partial pressure of gas A + Partial pressure of gas B
Total pressure = 0.298 atm + 0.589 atm → 0.887 atm
We convert the T° to Absolute value → 55°C + 273 = 328K
0.887 atm . 9.80L = n . 0.082 . 328K
(0.887 atm . 9.80L) /(0.082 . 328K) = 0.323 moles
These are the moles from the initial mixture, but we add 0.130 moles
Total new moles are 0.323 + 0.130 = 0.453 moles
P = (0.453 mol . 0.082 . 328K) / 9.80L
P = 1.24 atm
Notice, that the pressure was increased. As we add a third gas, the pressure is correctly increased because the molecules from all of the gases collide more with the walls of the vessel.
Which equation should you use to find the final
concentration?
Answer:
Mf = MiVi / Vf
Explanation:
To obtain the answer to the question given, let us obtain the equation for the final concentration.
This can be obtained from the dilution equation as shown below :
MiVi = MfVf
Mi is the initial concentration
Mf is the final concentration
Vi is the initial volume
Vf is the final volume.
Making Mf the subject of the above equation, we can obtain the equation which can be used to calculate the final concentration. This is illustrated below:
MiVi = MfVf
Divide both side by Vf
Mf = MiVi / Vf
Therefore, the equation which can be used to calculate the final concentration is Mf = MiVi / Vf
The first part to this question is:
What is the final volume? 150.0
the second part:
Which equation should you use to find the final concentration? 3rd option
The 3rd part:
What is the new concentration? 0.125 M NaCl
Explanation:
On edg.. Good Luck!!
what is the mass of one mole of oxygen gas?
Answer:
32 grams
Explanation:
To find the molar mass of oxygen gas, you need to take a look at it's molecular formula. Oxygen is O2, and since each oxygen molecule has a molar mass of 16, 2 of them together have a molar mass of 32 grams. Hope this helps!
What is the molar mass of acetylsalicylic acid (Aspirin)? (HC₉H₇O₄)
Answer:
180 g/mol
Explanation:
M(HC₉H₇O₄) = M(H) + 9M(C) + 7M(H) + 4M(O) = 1+ 9*12 +7*1 + 4*16= 180
The molar mass of Aspirin (C9H8O4) is calculated as 180.17 g/mol, by summing the individual contributions of the atomic masses of carbon, hydrogen, and oxygen.
Explanation:The molar mass of acetylsalicylic acid, commonly known as Aspirin, can be calculated by adding the atomic masses of its constituent atoms. Aspirin has the molecular formula C9H8O4. To calculate the molar mass, we sum the atomic masses as follows:
Carbon (C): 12.01 g/mol x 9 atoms = 108.09 g/molHydrogen (H): 1.01 g/mol x 8 atoms = 8.08 g/molOxygen (O): 16.00 g/mol x 4 atoms = 64.00 g/molAdding these contributions together, we get:
Molar mass of Aspirin (C9H8O4) = 108.09 + 8.08 + 64.00 = 180.17 g/mol
This value is slightly different from the reference value of 180.15 g/mol, likely due to rounding differences in the atomic masses used.
A 0.500-g sample of chromium metal reacted with sulfur powder to give 0.963 g of product. Calculate the empirical formula of the chromium sulfide.
Answer: The empirical formula for the given compound is [tex]Cr_2S_3[/tex]
Explanation : Given,
Mass of product = 0.963 g
Mass of Cr = 0.500 g
Mass of S = 0.963 g - 0.500 g = 0.463 g
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.
Moles of Cr =[tex]\frac{\text{Given mass of Cr}}{\text{Molar mass of Cr}}=\frac{0.500g}{52g/mole}=0.00962moles[/tex]
Moles of S = [tex]\frac{\text{Given mass of S}}{\text{Molar mass of S}}=\frac{0.463g}{32g/mole}=0.0145moles[/tex]
Step 2: Calculating the mole ratio of the given elements.
For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.00962 moles.
For Cr = [tex]\frac{0.00962}{0.00962}=1[/tex]
For S = [tex]\frac{0.0145}{0.00962}=1.5[/tex]
To make in a whole number we are multiplying the ratio by 2, we get:
The ratio of Cr : S = 1 : 1.5
The ratio of Cr : S = 2 : 3
Step 3: Taking the mole ratio as their subscripts.
The ratio of Cr : S = 2 : 3
Hence, the empirical formula for the given compound is [tex]Cr_2S_3[/tex]
You use energy to heat your home. What ultimately happens to the energy that you pay for in your heating bill?
1. The energy escapes your home and heats the outside.
2. The energy heats your home.
3. The energy disappears as it never exists.
4. The energy changes to mass.
Answer:
1. The energy escapes your home and heats the outside.
Explanation:
Final answer:
The energy used to heat your home ultimately dissipates into the environment, adhering to the First Law of Thermodynamics, which states that energy is neither created nor destroyed. Thus, we can say option A is correct.
Explanation:
When you pay for energy to heat your home, the energy initially heats your home. Over time, this energy eventually dissipates into the environment, resulting in what we perceive as loss of heat. Contrary to the idea of energy vanishing or turning into mass, the First Law of Thermodynamics assures us that energy is neither created nor destroyed but simply changes form. For instance, the heat produced by your furnace or heat pump eventually escapes to the outside. This process is an inherent part of nearly all energy usage; energy used for work or heating almost always winds up as thermal energy in the end.
A gas has a pressure of 410 atm and a volume of 32 L. At what pressure would the volume of the gas change to 28L?
Answer:
At 468.57 atm pressure the gas volume would change to 28 L.
Explanation:
Boyle's law states that the pressure of a gas in a closed container is inversely proportional to the volume of the container, when the temperature is constant.
This law can be expressed mathematically as:
P · V = k
where P is pressure, V is volume and k is a constant.
This formula can be used to determine the change in pressure or volume during an isothermal transformation (i.e. the temperature is constant) as follows:
P1 · V1 = P2 · V2
In this case,
P1= 410 atmV1= 32 LP2= ?V2= 28 LReplacing:
410 atm*32L= P2*28 L
Solving:
[tex]P2=\frac{410 atm*32 L}{28L}[/tex]
P2=468.57 atm
At 468.57 atm pressure the gas volume would change to 28 L.
Jorge inflates a beach ball to a volume of 4L in his air-conditioned house where the temperature is 18℃. That afternoon he takes the beach ball to the beach with some friends. The temperature at the beach is 32℃, and the air pressure at the beach is the same as it was at Jorge's house. What will happen to Jorge's beach ball when he is at the beach? Choose the claim that best answers the question: * 1 point The beach ball will get smaller at the beach because the molecules are moving slower. The beach ball will stay the same size at the beach because the pressure is constant. The beach ball will get larger at the beach because the molecules are moving faster. The beach ball will get larger at the beach because the pressure will cause it to expand. The beach ball will get smaller at the beach because the molecules will collide less often.
Answer:
The beach ball will get larger at the beach because the molecules are moving faster.
Explanation:
We can answer this problem by using Charle's Law, which states that:
"For a constant mass of an ideal gas kept at constant pressure, the volume of the gas is directly proportional to its temperature"
Mathematically:
[tex]V\propto T[/tex]
where
V is the volume of the gas
T is the absolute temperature of the gas
Here, we are analyzing the air inside the ball (the gas). We are also told that when the ball is brought to the beach, the pressure does not change: therefore, we can apply Charle's Law.
We are told that when the ball is brought to the beach, the temperature increases from 18℃ to 32℃: therefore, since the volume of the air (and the ball) is proportional to the temperature, this means that the volume of the ball will increase as well.
The reason for this is that the ball is not thermally isolated, so the molecules of the air inside the ball reach soon the same temperature of the surroundings, and so they will move faster (higher temperature means higher average kinetic energy of the molecules, so the molecules move faster, and therefore the ball will expand).
So the correct option is
The beach ball will get larger at the beach because the molecules are moving faster.
Jorge's beach ball when he is at the beach should be beach ball will get larger at the beach because the molecules are moving faster.
What should be happening for beach ball?Here we applied Charle law, in this the volume of the gas is directly proportional to its temperature. Here the ball should not be isolated due to this it moved faster i.e. if there is high temperature that means there should be high kinetic energy so the molecules should be moved quicker due to this the ball should be expanded.
Learn more about molecule here: https://brainly.com/question/19531144
A chemist needs 225 ml of 2.4 m hcl. What volume of 12 m hcl must be mixed with water to form this solution?
To determine the volume of 12 M hydrochloric acid (HCl) needed to prepare 225 mL of 2.4 M HCl, you apply the dilution equation C1V1 = C2V2 and solve for V1.
The subject of this question is determining the volume of a concentrated hydrochloric acid (HCl) solution needed to prepare a more dilute solution of HCl.
We use the equation C1V1 = C2V2 where C1 is the concentration of the starting solution (12 M HCl), V1 is the volume of the starting solution we need to find, C2 is the concentration of the final solution (2.4 M HCl), and V2 is the volume of the final solution (225 mL).
Plugging the values into the equation gives us: (12 M)V1 = (2.4 M)(225 mL).
Therefore, V1 = (2.4 M)(225 mL) / (12 M).
By calculating V1, we get the volume of 12 M HCl needed to make 225 mL of 2.4 M HCl.
Balance each of the chemical equations below. (Some equations may already be
in balance.) In the space to the right, classify the reaction as a synthesis, decomposition,
single replacement, or double replacement reaction.
A. ___ AgNO3 + ___ KCl⇒ ___ AgCl + ___ KNO3 _______________________
B. ___ H2O + ___ SO3 ⇒ ___ H2SO4 _______________________
C. ___ KI + ___ Cl2 ⇒ ___ KCl + ___ I2 _______________________
D. ___ NaHCO3 ⇒___ Na2CO3 + ___ H2O + ___ CO2 _______________________
E. ___ Zn + ___ HCl ⇒ ___ ZnCl2 + ___ H2 _______________________
F. ___ BaCl2 + ___ Na2SO4 ⇒ ___ BaSO4 + ___ NaCl _______________________
G. ___ C3H8 + ___ O2 ⇒ ___ CO2 + ___ H2O _______________________
H. ___ Al + ___ CuCl2 ⇒ ___ AlCl3 + ___ Cu _______________________
i will give 80 points and brainliest answer to the first one that answers
Answer:
A. 1 AgNO3 + 1 KCl ⇒ 1 AgCl + 1 KNO3 double replacement
B. 1 H2O + 1 SO3 ⇒ 1 H2SO4 synthesis
C. 2 KI + 1 Cl2 ⇒ 2 KCl + 1 I2 single replacement
D. 2 NaHCO3 ⇒ 1 Na2CO3 + 1 H2O + 1 CO2 decomposition
E. 1 Zn + 2 HCl ⇒ 1 ZnCl2 + 1 H2 single replacement
F. 1 BaCl2 + 1 Na2SO4 ⇒ 1 BaSO4 + 2 NaCl double displacement
G. 1 C3H8 + 5 O2 ⇒ 3 CO2 + 4 H2O combustion
H. 2 Al + 3 CuCl2 ⇒ 2 AlCl3 + 3 Cu single displacement
Explanation:
Use algebra to make sure you have the same amount of each element on each side (Reactants and Products) and only change the coefficients of the compounds and elements!
double displacement: AB + CD ⇒ AD + CB
single replacement: AB + C ⇒ A + CB
decomposition: A ⇒ B + C
synthesis: A + B ⇒ C
combustion: any reaction that involve oxygen and don't follow any of the previous reactions
To balance a chemical reaction equation, the number of atoms of each element on both sides of the reaction equation must be the same.
A chemical reaction equation has a right hand side (reactants side) and a left hand side (products side). The reactants combine to give the products. The number of atoms of each element on the reactants side must be exactly the same as the number of atoms of the same element on the products side.
The balanced chemical reaction equation for each of the reactions is shown below;
AgNO3 + KCl ------>AgCl + KNO3 double replacement reactionH2O + SO3 -------> H2SO4 synthesis reaction2KI + Cl2 ------> 2 KCl + I2 single replacement reaction 2NaHCO3 ----> Na2CO3 + CO2 + H2O decomposition reactionZn + 2HCl -----> ZnCl2 + H2 single replacement reaction BaCl2 + Na2SO4 ------> 2NaCl + BaSO4 double replacement reactionC3H8 + 5O2 ------> 3CO2 + 4H2O Combustion reaction2Al + 3CuCl2 -----> 2AlCl3 + 3Cu single replacement reactionIf there is no molar coefficient written in front of any of the species then the molar is 1.
Learn more: https://brainly.com/question/1388366
A scientist is comparing two cells.
One cell, cell A, is from a unicellular organism, and the other cell, cell B, is from a multicellular organism.
What functional differences will the scientist most likely see when comparing the two cells?
A. Cell A performs all of the organism's necessary functions, while cell B only performs one or a few functions.
B. Cell A is very large and has many organelles, while cell B is very small and has only a few organelles
C. Cell A performs only one or a few functions, while cell B performs all of the organism's necessary functions.
D. Cell A is very small and has only a few organelles, while cell B is large and has many organelles
Answer: Cell A performs all of the organism's necessary functions, while cell B performs only one or a few functions.
how do scientist determine weather a cell from cancerous tissue is a cancer stem cell
Answer:
Researchers take samples of tumors removed from patients during surgery, always with the patient's informed consent. The cells within the tumor are then sorted based on their expression of certain cell markers on their surface.
Explanation:
A compound that can act as an acid or a base is referred to as
Answer:
An amphoteric substance
Explanation:
Answer:
An atmospheric substance
For example is an aluminum hydroxide is atmospheric because it can act as a base and neutralize strong acids
When 38.0 g of N2 is reacted with H2 and 40.12 g of NH3 are produced, what is the percent yield?
Answer:
52.80 % is the percent yield of the reaction.
Explanation:
Mass of nitrogen gas = 38.0 g
Moles of nitrogen = [tex]\frac{38.0g}{17 g/mol}=2.235 mol[/tex]
[tex]3H_2+N_2\rightarrow 2NH_3[/tex]
According to reaction, 1 moles of nitrogen gas gives 2 moles of ammonia, then 2.235 moles of nitrogen will give:
[tex]\frac{2}{1}\times 2.235mol=4.470 mol[/tex] ammonia
Mass of 4.470 moles of ammonia
= 4.470 mol × 17 g/mol = 75.99 g
Theoretical yield of ammonia = 217.8 g
Experimental yield of ammonia = 40.12 g
The percentage yield of reaction:
[tex]=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100[/tex]
[tex]=\frac{40.12 g}{75.99 g}\times 100=52.80\%[/tex]
52.80 % is the percent yield of the reaction.
If the reactants of a reaction are HCI and NaOH, what could be a product? A. NO2,B.HCIO4,C.NaCl,D.Na2CO3
Answer:
C. NaCl
Explanation: The answer is C because the products are water and salt. Hydrochloric acid is a strong acid and NaOH ( sodium hydroxide is also a strong acid) are the reactants.
Answer:
NaCI
Explanation:
Carbon monoxide and chlorine gas react to produce COCl2 gas. The Kp for the reaction is 1.49 × 108 at 100.0 °C: In an equilibrium mixture of the three gases, PCO, = PCl2 = 7.70 × 10-4 atm. The partial pressure of the product, phosgene (COCl2), is ________ atm. Use the assumption that change in x is small so you do not have to use the quadratic.
Answer:
Explanation:
Solution:
For the equilibrium
The equilibrium constant is defined in terms of partial pressure:
Introducing the numerical data given for partial pressureof carbon monoxide 0 and chlorine 12, also the value for equilibrium constant:
Answer:
The partial pressureof the product, phosgene (COCl2), is 29.4atm
Answer:
88.34 atm
Explanation:
At equilibrium, carbon monoxide (CO) would react with chlorine gas according to the equation below:
CO (g) + Cl₂ (g) ⇒ COCl₂ (g)
The equilibrium constant Kp, which is a ratio of the partial pressure of the product to that of the reactants is obtained from the equation below:
Kp = PCOCL / PCO.PCl₂
From the question given,
Kp = 1.49 x 10⁸ t 100° C
PCO = 7.70 X 10⁻⁴ atm
PCl₂ = 7.70 x 10⁻⁴ atm
It therefore implies that,
1.49 x 10⁸ = P(COCl₂) / (7.70 x 10⁻⁴). (7.70 x 10⁻⁴)
P(COCl₂) = 1.49 x 10⁸) . (7.70 x 10⁻⁴) . (7.70 x 10⁻⁴)
P (COCl₂) = 88.34 atm
The partial pressure P(COCl₂) of the product phosgene (COCl₂) is 88.34 atm
A balloon containing helium gas expands from 230
mL to 860 mL as more helium is added. What was
the initial quantity of helium present if the
expanded balloon contains 3.8 x 10-4 mol,
assuming constant temperature and pressure?
Which of the variables are known?
DONE
The answer for the following problem is mentioned below.
Therefore the final moles of the gas is 14.2 × [tex]10^{-4}[/tex] moles.Explanation:
Given:
Initial volume ([tex]V_{1}[/tex]) = 230 ml
Final volume ([tex]V_{2}[/tex]) = 860 ml
Initial moles ([tex]n_{1}[/tex]) = 3.8 ×[tex]10^{-4}[/tex] moles
To find:
Final moles ([tex]n_{2}[/tex])
We know;
According to the ideal gas equation;
P × V = n × R × T
where;
P represents the pressure of the gas
V represents the volume of the gas
n represents the no of the moles of the gas
R represents the universal gas constant
T represents the temperature of the gas
So;
V ∝ n
[tex]\frac{V_{1} }{V_{2} }[/tex] = [tex]\frac{n_{1} }{n_{2} }[/tex]
where,
([tex]V_{1}[/tex]) represents the initial volume of the gas
([tex]V_{2}[/tex]) represents the final volume of the gas
([tex]n_{1}[/tex]) represents the initial moles of the gas
([tex]n_{2}[/tex]) represents the final moles of the gas
Substituting the above values;
[tex]\frac{230}{860}[/tex] = [tex]\frac{3.8 * 10^-4}{n_{2} }[/tex]
[tex]n_{2}[/tex] = 14.2 × [tex]10^{-4}[/tex] moles
Therefore the final moles of the gas is 14.2 × [tex]10^{-4}[/tex] moles.
Answer:
1.0 × 10-4 mol
Or just A. The first one
Explanation:
Just did it on eg
The middle ear converts sound from what into vibrations that can be sent through what?
Answer:
The vibrations are then passed to 3 tiny bones in the middle ear called the ossicles. The ossicles amplify the sound. They send the sound waves to the inner ear and into the fluid-filled hearing organ (cochlea). Once the sound waves reach the inner ear, they are converted into electrical impulses.
Calculate the ph of the solution resulting from the addition of 85.0 ml of 0.35 m hcl to 30.0 ml of 0.40 m aniline (c6h5nh2). kb (c6h5nh2) = 3.8 x 10-10
Answer:
pH = 0.81
Explanation:
HCl reacts with aniline, thus:
C₆H₅NH₂ + HCl → C₆H₅NH₃⁺ + Cl⁻
Moles of HCl are:
0.085L × (0.35mol HCl / L) = 0.02975mol HCl
Moles of aniline are:
0.030L × (0.40mol HCl / L) = 0.012mol aniline
Thus, after reaction, will remain:
0.02975mol - 0.012mol = 0.01775mol HCl
Moles of HCl in solution are equal to moles of H⁺, thus, moles of H⁺ are: 0.01775mol H⁺
As total volume is 85.0mL + 30.0mL = 115.0mL ≡ 0.115L
0.01775mol / 0.115L = 0.1543M
pH of solution = -log[H⁺]
pH = -log 0.1543M
pH = 0.81
Answer:
pH = 0.81
Explanation:
Step 1: Data given
Volume of a 0.35 M HCl solution = 85.0 mL
Volume of a 0.40 M aniline solution = 30.0 mL
Kb of aniline = 3.8 * 10^-10
Step 2: The balanced equation
C6H5NH2 + HCl → C6H5NH3+ + Cl-
Step 3: Calculate moles
Moles = molarity * volume
Moles HCl = 0.35 M * 0.085 L
Moles HCl = 0.02975 moles
Moles aniline = 0.40 M * 0.030 L
Moles aniline = 0.012 moles
Step 4: Calculates limiting reactant
Aniline is the limiting reactant. It will completely be consumed (0.012 mole)
HCl is in excesS. There will react 0.012 moles. There will remain 0.02975 - 0.012 = 0.01775 moles
Step 5: Calculate molarity HCl
Molarity HCl = moles HCl / total volume
Molarity HCl = 0.01775 moles / 0.115 L
Molarity HCl = 0.154 M
Step 6: Calculate pH
pH = -log[H+]
pH = -log[0.154]
pH = 0.81
nitrogen + oxygen → nitrogen dioxide
Which of these is a reactant in this chemical reaction?
A) H2O
B) N2
C) N2O
D) NO2
Answer:
no2
Explanation:
Nitrogen N and Oxygen O2 combine to form NO2
What is the concentration of a calcium hydroxide solution, if 35.00 mL of the base is completely neutralized by 12.0 mL of 0.0338 M HCl?
Answer:
0.00579 M
Explanation:
Concentration of acid CA= 0.0338 M
Volume of acid VA= 12.0mL
Concentration of base CB= ??????
Volume of base VB= 35.00mL
Now we must write the equation of the reaction:
Ca(OH)2(aq) + 2HCl(aq) ------> CaCl2(aq) + 2H2O(l)
We can now write the number of moles of acid and base
Number of moles of acid NA= 2
Number of moles of base NB= 1
From:
CAVA/CBVB = NA/NB
CAVANB = CBVBNA
CB= CA VA NB/ VB NA
CB=0.0338 × 12.0 × 1/ 35.0 × 2
CB= 0.00579 M
The molar enthalpy of vaporization of water is 40.79 kJ/mol, and the molar enthalpy of fusion of ice is 6.009 kJ/mol. The molar mass of water is 18.02 g/mol. How much energy is absorbed when 30.3 g of liquid water boils
Answer : The amount of energy absorbed is, 81.2 kJ
Explanation :
The process involved in this problem are :
[tex](1):H_2O(l)(0^oC)\rightarrow H_2O(l)(100^oC)\\\\(2):H_2O(l)(100^oC)\rightarrow H_2O(g)(100^oC)[/tex]
The expression used will be:
[tex]Q=[m\times c_{p,l}\times (T_{final}-T_{initial})]+[m\times \Delta H_{vap}][/tex]
where,
[tex]Q[/tex] = heat required for the reaction = ?
m = mass of liquid = 30.3 g
[tex]c_{p,l}[/tex] = specific heat of liquid water = [tex]4.18J/g^oC[/tex]
[tex]\Delta H_{vap}[/tex] = enthalpy change for vaporization = [tex]40.79kJ/mol=\frac{40790J/mol}{18.02g/mol}=2263.6J/g[/tex]
Now put all the given values in the above expression, we get:
[tex]Q=[30.3g\times 4.18J/g^oC\times (100-0)^oC]+[30.3g\times 2263.6J/g][/tex]
[tex]Q=81252.48J=81.2kJ[/tex]
Therefore, the amount of energy absorbed is, 81.2 kJ
What is the volume of 2.3 mol of helium at 17 C and 0.89 atm? Assume helium behaves as an ideal gas.
Answer:
39.446L
Explanation:
since helium is ideal gas, we can use PV = nRT
P = pressure
V = volume
n = moles
R = gas constant
T = temperature in Kelvin
we are solving for V
V = [tex]\frac{nRT}{P}[/tex]
C to K temp transfer: K = C + 273, so K = 290 since C = 17
our gas constant is 0.08206 atm L/mol K, this gas constant r will change depending on what unit of pressure you are using (mmHg, atm, etc).
plug and chug
V = [tex]\frac{(2.3mol)(290K)(\frac{0.08206 atmL}{molK}) }{1 atm}[/tex]
canceling out units
V = [tex]\frac{2.3 * 209 * 0.08206L}{1}[/tex] = 39.446
Choose all of the statements below that are true about Avogadro's number and the mole:
A) A mole is a counting unit
B) Avogadro's number is to the mole what "12" is to a "dozen" or what "2" is to a "pair"
C) We can use a conversion factor with Avogadro's number in it to determine the number of particles, atoms and/or molecules in a substance of given moles.
D) A mole simply means 6.022 x 10^23 of something (atoms, molecules, particles)
E) Avogadro's number is 6.022
A, B, C, D
Explanation:
Avogadro number is a constant at 6.022 x 10^23. The number is equivalent to a mole in Chemistry. It stipulates the number of particles expected in a mole of a substance. This unit of measurement is named after its inventor, Amedeo Avogadro, an Italian scientist.
It is also used to derive the molar mass of a substance. Dalton is used in expressing the mass of a mole of a substance– atomic mass unit (AMU) * Mass Number.
A gas sample containing 1.45 mol at 25°C exerts a pressure of 408 torr. Some gas is added to the same container, and the temperature is increased to 50.°C. If the pressure increases to 800. torr, how many moles of gas were added to the container? Assume a constant-volume container.
Answer:
It were added 1.17 moles of gas
Explanation:
We use the Ideal Gases Law to propose both situations:
P . V = n . R . T
For initial situation → P₁ . V₁ = n₁ . R . T₁
For the second situation → P₂ . V₂ = n₂ . R . T₂
R is a constant and V remains constant, so we cancel from the equations.
(n₁ . T₁) / P₁ = (n₂ . T₂) / P₂
Notice that n₂ = n₁ + x where n₁ = 1.45 moles.
Let's make the conversions for the units
25°C + 273 = 298 K (T₁) and 50°C + 273 = 323K (T₂)
408 Torr . 1 atm / 760 Torr = 0.537 atm (P₁)
800 Torr . 1 atm / 760 Torr = 1.05 atm (P₂)
Let's replace and find the x
(1.45 mol . 298K) / 0.537 atm = (( x + 1.45mol) . 323K) / 1.05 atm
(1.45 mol . 298K) / 0.537 atm . 1.05 atm = ( x + 1.45mol) . 323K
845 mol. K = 323 x K + 468.35 mol.K
845 mol.K - 468.35 mol.K = 323 x K
376.65 mol.K / 323 K = x
1.17 mol = x
A mutation occurs in a cell. Which sequence best represents the correct order of the events involved for this mutation to affect the traits expressed by this cell
Answer: A change in the sequence of DNA bases--> Joining amino acids in sequence --> Appearance of characteristics
Explanation:
A mutation is a permanent shift or change from the normal DNA sequence that makes up a gene and affect traits which makes the sequence becomes different from what is commonly found in people. Mutations vary from distortion of a single DNA building block to a large segment of a chromosome.
When mutation occurs in a cell, for the mutation to affect the traits expressed by the particular cell, it must follow this sequence directly:
A change in the sequence of DNA bases--> Joining amino acids in the sequence --> Appearance of characteristics.
The correct sequence is: D) A change in the sequence of DNA bases --->Joining amino acids in sequence ----> Appearance of characteristic
The correct sequence for a mutation to affect cell traits is: a change in the DNA sequence, then joining amino acids in sequence, and finally the appearance of the characteristic.
This order ensures that DNA mutations lead to altered proteins, which result in changed traits.For a mutation to affect the traits expressed by a cell, the events follow a specific sequence.The correct sequence is:
A change in the sequence of DNA basesJoining amino acids in sequenceAppearance of characteristicThis sequence follows the principle that mutations in DNA alter the nucleotide sequence, which in turn changes the amino acid sequence in the proteins produced.
These protein changes can then manifest as different traits or characteristics in the organism.For example, in the case of Sickle Cell Anemia, a single base-pair substitution in the hemoglobin gene results in a different amino acid sequence, altering the shape and function of red blood cells.
Correct question is: A mutation occurs in a cell. Which sequence best represents the correct order of the events involved for this mutation to affect the traits expressed by this cell?
A) a change in the sequence of DNA bases ----> joining amino acids in sequence appearance of characteristic
B) joining amino acids in sequence ---> a change in the sequence of DNA bases appearance of characteristic
C) appearance of characteristic rarr joining amino acids in sequence ---> a change in the sequence of DNA bases
D) a change in the sequence of DNA bases ----> appearance of characteristic ---> joining amino acids in sequence
A concentration cell consists of two Sn/Sn2+ half-cells. The electrolyte in compartment A is 0.10 M Sn(NO3)2. The electrolyte in B is 0.87 M Sn(NO3)2. Which half-cell houses the cathode? What is the voltage of the cell? Cathode: half-cell A half-cell B Voltage of cell: V
Answer:
In compartment A, the solution will be concentrated with respect to compartment B, however, over time both compartments will have the same concentration. In compartment B it houses the cathode.
the voltage of the cell is 0.0315 V
Explanation:
Given:
Electrolyte in compartment A is 0.10 M
Electrolyte in compartment B is 0.87 M
Questions:
Which half-cell houses the cathode?
What is the voltage of the cell, V = ?
In both compartments, the reactions are:
A: Sn → Sn²⁺ + 2e⁻
B: Sn²⁺ + 2e⁻ → Sn
In compartment A, the solution will be concentrated with respect to compartment B, however, over time both compartments will have the same concentration. In compartment B it houses the cathode.
The voltage of the cell
[tex]V=E_{in} -\frac{0.0592}{nlog(C_{A} /C_{B} )}[/tex]
Here
n = 2 due the two electrons transferred
Ein = 0
Substituting values:
[tex]V=0-\frac{0.0592}{2*log(0.1/0.87)} =0.0315V[/tex]