Answer:
Half-lives of first order reactions
[A]1/2[A]o=12=e−kt1/2.
ln0.5=−kt.
t1/2=ln2k≈0.693k.
But volcanoes are not all bad. Can you assess the value of volcanoes for the Earth? Why are they necessary and what good do they do?
Answer:
yes
Explanation:
volcanoes have done wonderful things for the earth
They help cool off the earth removing heat from its interiorvolcanic emissions have produced the atmosphere and the water of the oceansvolcanoes make islands and add to the continentvolcanoes are necessary because:
fertile is another advantage of volcanic activity."In places like Japan,Indonesia,Philippines,Hawaii,volcanic material mixed in with the soil provides a lot of important nutrients
Consider the following half-reactions and their standard reduction potential values to answer the following questions.
Cu2+ (aq) + e- Cu+ (aq) E° = 0.15 V
Br2 (l) + 2e- 2Br- (aq) E° = 1.08 V
i) State which reaction occurs at the anode and which at the cathode. [2 marks]
ii) Write the overall cell reaction. [2 marks]
iii) Calculate the value of E°cell. [2 marks]
iv) Calculate the value ΔG° [2 marks]
v) What is the value of Kc at 25°C? [2 marks]
Answer:
Br2 (l) + 2e- ---------> 2Br- (aq) E° = 1.08 V cathode
Cu2+ (aq) + e- --------->Cu+ (aq) E° = 0.15 V anode
Explanation:
We have to first state the fact that the reaction having the most positive reduction potential occurs at the cathode in any spontaneous electrochemical cell. The half reaction with the less positive electrode potential usually occurs at the anode.
The overall reaction equation is;
2Cu2+ (aq) + Br2 (l) ----->2Cu+ (aq) + 2Br- (aq)
E°cell= E°cathode - E°anode
E°cathode= 1.08 V
E°anode= 0.15V
E°cell = 1.08-0.15 = 0.93 V
But
∆G°= -nFE°cell
n= 2, F=96500C, E°cell= 0.93V
∆G° = -(2× 96500× 0.93)
∆G= -179490 J
But;
∆G = -RTlnK
R=8.314 JK-1
T= 25+273= 298K
Kc= the unknown
∆G° = -179490 J
Substituting values and making lnK the subject of the formula
lnK= ∆G/-RT
lnK= -( -179490/8.314 × 298)
lnK= 72.45
K= e^72.45
K= 2.91×10^31
amning At Home -Chemisu
Use the specific heat values to answer the
following questions.
Cp (J/g•°C)
4.18
Which of the following has the smallest heat
capacity?
2.03
2.08
0.450
RETRY
Substance
H2O(1)
H2O(s)
H2O(g)
Fe(s)
Al(s)
Cu(s)
Sn(s)
Pb(s)
Au(s)
Hg(1)
0.897
0.385
0.227
0.129
0.129
0.140
Intro
Answer:first one: 3.0g second one: 10g H2O(I)
Explanation:
Answer:
First blank: 3.0 g Pb
Second Blank: 10g [tex]H_{2} O[/tex](l)
Explanation:
Edge '21
A scientist places a strip of hot metal on top of a block of another metal with a lower
melting point. The second metal quickly melts. What is the main type of heat transfer
responsible?
The heat transfer that we'll have will be:
- At first, the metal bar will emanate heat through radiation, to the atmosphere, and to the second metal, through conduction.
- Because of this, the second bar will start to increase it's temperature, up to the fusion point, spending the energy received on the fusion, and also radiating heat to the atmosphere. It won't emit heat in any other form, since heat transmission can happen only from a hot body to a cooler one, and the only things in contact are the two bars.
Answer:
conduction
Explanation:
they are in direct contact
In what way are Paul Robeson and Sonia Sotomayor alike?
A. All the above
B They both started ethnic studies programs in their hometowns .
C. They are both people of color who were the first to do something in their fields.
D. They are both Hispanic.
Answer:
C is the answer.
Explanation:
They are both people of color who were the first to do something in their fields
Calculate the value deltaG°
Answer:
ΔG=ΔG0+RTlnQ where Q is the ratio of concentrations (or activities) of the products divided by the reactants. Under standard conditions Q=1 and ΔG=ΔG0 . Under equilibrium conditions, Q=K and ΔG=0 so ΔG0=−RTlnK . Then calculate the ΔH and ΔS for the reaction and the rest of the procedure is unchanged.
Explanation:
A metal, M , of atomic mass 56 amu reacts with chlorine to form a salt that can be represented as MClx. A boiling point elevation experiment is performed to determine the subscript , and therefore, the formula of the salt. A 30.2 g sample of the salt is dissolved in 100.0 g of water and the boiling point of the solution is found to be 376.81 K. Find the formula of the salt. Assume complete dissociation of the salt in solution.
CAN SOMEONE PLEASE HELP ME!!! I AM VERY CONFUSED AND ITS DUE TODAY BEFORE 11:55 THANK YOU IN ADVANCED
Answer:
MCl₂
Explanation:
The formula for boiling point elevation can be used to find x. The "complete dissociation" means there will be an ion of M and x ions of Cl in the solution. The number of moles of solute will be 30.2 grams divided by the molecular weight of MClx, where x is the variable we're trying to find.
[tex]\Delta T=imK_b\qquad\text{where i=ions/mole, m=molality, $K_b\approx 0.512$}\\\\376.81-373.15=(x+1)\dfrac{\text{moles}}{\text{kg solvent}}(0.512)\\\\\dfrac{3.66}{0.512}=(x+1)\dfrac{\dfrac{30.2}{56+35.45x}}{0.1}=\dfrac{302(x+1)}{56+35.45x}\\\\\dfrac{3.66}{0.512\cdot 302}(56+35.45x)=x+1\\\\\dfrac{3.66\cdot 56}{0.512\cdot 302}-1=x\left(1-\dfrac{3.66\cdot 35.45}{0.512\cdot 302}\right)\\\\x=\dfrac{50.336}{24.877}\approx 2.023[/tex]
Then the formula for the salt is MCl₂.
What is the total pressure in a 2.00 L container that holds 1.00g He, 14.0g CO, and 10.0g of NO at 27 degree?
Answer:
13.3 atm(assuming the temperature given is in Celsius)
Explanation:
First, the moles of each gas must be found. .25 mol He, .50 mol CO, .33 mol NO. Next, each set of mols must be plugged into the ideal gas law, PV=nRT, for each gas. Move it around so you get the pressure P=nRT/V. When you calculate everything, you should get 3.08atm He, 6.15atm CO, and 4.06atm NO. Add these together and you get the pressure of the container.
a. Use the following data to calculate the enthalpy of hydration for calcium chloride and calcium iodide.
Lattice Energy* ΔHsoln
CaCl_2(s) -2247 kJ/mol -46 kJ/mol
CaI_2(s) -2059 kJ/mol -104 kJ/mol
*Lattice energy is defined as the energy change for the process M^+(g) + X^-(g) -------> MX(s).
b. Based on your answers to part a, which ion, Cl^- or I^-, is more strongly attracted to water?
O Chloride
O Iodide
Answer:
A. Enthalpy of hydration of CaCl2 = -2293 KJ/mol
Enthalpy of hydration of CaI2 = -2163 KJ/mol
B. Chloride ions
Explanation:
Enthalpy of hydration is the energy required to convert one mole of gaseous ions to aqueousions.
Enthalpy of hydration = Enthalpy of solution - lattice energy
For CaCl2;
Enthalpy of hydration = -46 - 2247 = -2293 KJ/mol
For CaI2;
Enthalpy of hydration = -104 - 2059 = -2163 KJ/mol
B. Since the enthalpy of hydration of CaCl2 is more negative than that of CaI2, it means that chloride ions are more easily attracted to water molecules. This we conclude because the difference in enthalpy values are due to the negative ions as the two compounds share a common positive calcium ion.
The enthalpy for hydration of calcium chloride is -2293 kJ/mol. The enthalpy for the hydration of calcium iodide is -2163 kJ/mol. The chloride ion Cl^- is more strongly attracted to water than iodide.
The enthalpy of hydration also the enthalpy of solvation is the quantity of energy released when 1 mole of gaseous ion is diluted.
It can be expressed by using the formula:
[tex]\mathbf{\Delta H_{hyd} = \Delta H_{solution} + \Delta H_{LE}}[/tex]
The enthalpy for hydration of calcium chloride can be expressed as:
[tex]\mathbf{\Delta H_{hyd(cacl_2)} = \Delta H_{solution(caci_2)} + \Delta H_{LE(caci_2)}}[/tex]
[tex]\mathbf{\Delta H_{hyd(cacl_2)} = -46 \ kJ/mol +-2247 \ kJ/mol}[/tex]
[tex]\mathbf{\Delta H_{hyd(cacl_2)} =-2293 \ kJ/mol}[/tex]
The enthalpy for the hydration of calcium iodide can be expressed as:
[tex]\mathbf{\Delta H_{hyd(cal_2)} = \Delta H_{solution(caI_2)} + \Delta H_{LE(caI_2)}}[/tex]
[tex]\mathbf{\Delta H_{hyd(cacl_2)} = -104 \ kJ/mol +-2059 \ kJ/mol}[/tex]
[tex]\mathbf{\Delta H_{hyd(cacl_2)} =-2163 \ kJ/mol}[/tex]
From the above calculation, we can see that the enthalpy of hydration of calcium chloride is greater than that of calcium iodide,
Therefore, we can conclude that the chloride ion Cl^- is more strongly attracted to water than iodide.
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pH and pOH Formulas
Concentration Formulas
pH = -log[H30)
[H30*) = 10-PH
pOH = -log(OH)
[OH] = 10-POH
pH + POH = 14.00
[H3O+][0] = 1.0 10-14
What is the hydronium (H30*) concentration of a solution with a pH of 3.60?
A 2.5 x 10^M
B 3.0 x 10-M
C 4.0 x 10M
D.
45* 10-11M
Answer:
A. 2.5 x 10^M
Explanation:
H+=10^-pH
- Hope that helps! Please let me know if you need further explanation.
Answer:
A. 2.5 x 10^M
Explanation:
i took the test and i got it correct (edmentum)
How do you think rocks form?
Answer:
Through gradual accumulation of sediments
Explanation:
5. Write word equations for the following reactions
a) Burning of Sulphur in oxygen
b) Burning of carbon in excess oxygen
c) Burning of Sulphur in presence of Iron fillings
Answer:
a) Sulphur + Oxygen → Sulphur dioxide
b) Carbon + Oxygen → Carbon dioxide
c) Sulphur + Iron → Iron sulphide
How do rockets work? What chemicals are used and what reactions happens with those chemicals to make a rocket fly?
Answer:
Chemical rocket engines use a fuel (something to burn) and an oxidiser (something to react with the fuel). ... As the propellant reacts inside a combustion chamber, the chemical reaction produces hot gases. It is the ejection of these rapidly expanding hot gases at high speed from the rocket nozzle that
( I found this on a website called Science Learning. Full credit to them and their work. Check it out for more information)
Briefly describe how a potentiometric pHmeter works. (Hint: Describe how the pH meter
measures the amount of H+ or OH- ions in a sample)
Answer:
A general instrument, which is used to determine the concentration of hydrogen ion within the aqueous solution is known as a pH meter. The meter helps in determining the alkalinity or acidity, which is articulated in the form of pH. It is also called a potentiometric pH meter as it helps in finding the variation in electrical potential between a reference electrode and a pH electrode. This electrical potential variation is associated with the pH of the solution.
The potentiometric pH meter comprises a pair of electrodes and a basic electronic amplifier, some may even comprise a combination electrode and some sort of display that demonstrates pH units. The potentiometric pH meter generally exhibits a reference electrode or a combination electrode, and a glass electrode. The probes or electrodes are administered within a solution whose pH values are needed to be determined.
As ice at 0°C changes to water at 0°C, the average kinetic energy of the ice molecules *
remains the same
increases
decreases
Answer:
increases
Explanation:because it cant decrease
Answer:
remains the same
Explanation:
A proton transfer reaction can occur when an aldehyde is placed in strong base, such as an alkoxide ion, producing an alcohol and a charged conjugate base that is resonance stabilized. In the left box, draw the curved arrows for the proton transfer. In the middle and right boxes, draw the two structures for the resonance-stabilized product as noted in the box-specific directions. Be sure to include all lone pairs and nonzero formal charges.
Hi, you have not provided structure of the aldehyde and alkoxide ion.
Therefore i'll show a mechanism corresponding to the proton transfer by considering a simple example.
Explanation: For an example, let's consider that proton transfer is taking place between a simple aldehyde e.g. acetaldehyde and a simple alkoxide base e.g. methoxide.
The hydrogen atom attached to the carbon atom adjacent to aldehyde group are most acidic. Hence they are removed by alkoxide preferably.
After removal of proton from aldehyde, a carbanion is generated. As it is a conjugated carbanion therefore the negative charge on carbon atom can conjugate through the carbonyl group to form an enolate which is another canonical form of the carbanion.
All the structures are shown below.
Q6. A student mixes 50.0 mL of 1.00 M Ba(OH)2 with 86.4 mL of 0.494 M H2SO4. Calculate the
mass of solid BaSO4 formed and the pH of the mixed solution.
The mass of solid BaSO4 formed - 7.64 grams. and the pH of the mixed solution - 13.13
We can calculate the mass of the Ba(OH)2 by calculating the moles each solution contains
volume of Ba(OH)2 -n(Ba(OH)2) = 1.00M x 0.05L
= 0.05 moles
The volume of H2SO4 is :0.494M x 0.0864L
= 0.04268 moles
According to balanced reaction 1 mole Ba(OH)2 react with 1 mole H2SO4 molar ratio between Ba(OH)2 to H2SO4 is 1:1 therefore to react with 0.05 mole Ba(OH)2 required H2SO4 = 0.05 mole but H2SO4 therefore H2SO4 is limiting reactant
Ba(OH)2 + H2SO4 ----> BaSO4 + 2 H2O
0.04268<--- 0.04268
The mixed solution is Ba(OH)2 with 0.05 - 0.04268= 0.0172 mole
The concentration of mixed solution is :0.0172:(0.05 + 0.0664)
= 0.1478 M
The pH of mixed solution is:Ba(OH)2 is strong base therefore dissociate completely and 1 mole of Ba(OH)2 form to mole of OH- ion therefore concentration of OH- is double than Ba(OH)2
14 - -log[0.1478]
= 14 - 0.83
= 13.13 pH
the mass of BaSO4 is0.0328 x ( 137 + 32 + 16 x 4 )
= 7.64 grams.
Thus, The mass of solid BaSO4 formed - 7.64 grams. and the pH of the mixed solution - 13.13
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3. What are the two types of mechanical waves?...
Answer:
longitudinal waves and transverse waves.
Explanation:
Mechanical Waves are waves which propagate through a material medium (solid, liquid, or gas) at a wave speed which depends on the elastic and inertial properties of that medium. There are two basic types of wave motion for mechanical waves: longitudinal waves and transverse waves.
The two types of mechanical waves are transverse waves and longitudinal waves.
How to explain them
Transverse waves are characterized by oscillations perpendicular to the direction of wave propagation. In this type of wave, the particles of the medium move in a direction perpendicular to the wave's motion. Examples of transverse waves include electromagnetic waves like light and radio waves, as well as waves on a string or water waves.
Longitudinal waves, on the other hand, have oscillations parallel to the direction of wave propagation. In these waves, the particles of the medium move in the same direction as the wave. Sound waves are a common example of longitudinal waves, as well as seismic waves.
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1. Chromium metal is reacted with 40.0mL of 3.0M tin (IV) chloride in the following reaction:
4Cr + 3SnCl4 --> 4CrCl3 + 3Sn
How many grams of tin will be produced? (3 marks) Please upload your work.
(Non-anonymous question )
Answer:
14.2 g
Explanation:
40.00 mL = 0.04000 L solution of SnCl4
3.0 M = 3.0 mol/L Molarity of solution of SnCl4
3.0 mol/L * 0.04000 L = 0.12 mol SnCl4
4Cr + 3SnCl4 --> 4CrCl3 + 3Sn
from reaction 3 mol 3 mol
given 0.12 mol x mol
x = 0.12 mol Sn
Molar mass (Sn) =118.71 g/mol
0.12 mol Sn * 118.71 g/mol≈ 14.2 g
By titration, it is found that 28.5 mL of 0.183 M NaOH(aq) is needed to neutralize 25.0 mL of HCl(aq). Calculate the
concentration of the HCl solution.
Answer:
0.209M
Explanation:
M1V1=M2V2
(28.5 mL)(0.183M)=(25.0mL)(M)
M2= 0.209M
*Text me at 561-400-5105 for private tutoring if interested: I can do homework, labs, and other assignments :)
By means of a schematic diagram show how a bacteria cell applied to the region of a cowpea root can end up becoming a nitrate ion which can be absorbed by a subsequent crop
Answer:
Nitrifying Bacteria are a group of aerobic bacteria important in the nitrogen cycle as converters of soil ammonia to nitrates, compounds usable by plants. An example is nitrosomonas or nitrobacter and species in that family.
The schematic diagram is attached below, which summarises the oxidation of ammonia or free nitrogen in the soil to nitrates for the cowpea plant's utilisation.
Indicate the direction of polarity of each of the following covalent bonds. Please just write a + or - not the bonds.
1. C ---- O
2. O ---- Cl3. O ----- F4. C ----- N5. Cl ----- C6. S ----- H7. S ----- Cl
Answer:
1. C+ ---- O-
2. O+ ---- Cl-
3. O+ ----- F-
4. C+ ----- N-
5. Cl- ----- C+
6. S- ----- H+
7. S+ ----- Cl -
Explanation:
Electronegativity determines the polarity . There may be two atoms in a bond with high electronegativity, in such cases the positive charge is given to atom with comparatively lower electronegativity. Electronegativity determines the easiness with which an atom attract electrons in a chemical bond. A polar bond is formed when the difference in the electronegativity of two combining atoms is between 0.4 and 1.7. The correct direction is
1. C+ ---- O-
2. O+ ---- Cl-
3. O+ ----- F-
4. C+ ----- N-
5. Cl- ----- C+
6. S- ----- H+
7. S+ ----- Cl -
How many milliliters of 12.0 M hydrochloric acid contain 3.646 g of HCl (36.46 g/mol)?
Group of answer choices
Answer:
8.3ml of 12M HCl contains 3.646 grams HCl
Explanation:
moles HCl = Molarity X Volume => Volume (Liters) = moles HCl/Molarity
Vol(L) = (3.646g/36.46g/mole)/12M = 0.0083Liter x 1000ml/L = 8.3ml
convert 200 grams N to moles
Answer: 14.278880821321199
Explanation:
Answer:
521.12323
Explanation:
I need help with this i'm really dumb.
Balance
p4+o2 ----> p4o10
Answer:
P4 + 5O2 → P4O10
Explanation:
White Phosphorus - P4
Dioxygen - O2
Tetraphosphorus Decaoxide - P4O10
In a neutralization reaction with a strong acid or base, all of the hydrogens from the acid and the hydroxides from the base react to form water.
Balance the following neutralization reaction:
H3PO4 (aq) + NaOH (aq) â H2O (l) + Na3PO4 (aq)
Enter the appropriate coefficient to the left of the respective term. In the event that your coefficient would be "1" be sure to write "1" as opposed to leaving it blank.
Answer:
H3PO4 + 3NaOH ----> Na3PO4 + 3H2O
Explanation:
The balanced equation is given below
H3PO4 + 3NaOH ----> Na3PO4 + 3H2O
Answer:
[tex]H_3PO_4 (aq) + 3NaOH (aq) \rightarrow 3H_2O (l) + Na_3PO_4 (aq)[/tex]
Explanation:
Hello,
In this case, for the given reaction:
[tex]H_3PO_4 (aq) + NaOH (aq) \rightarrow H_2O (l) + Na_3PO_4 (aq)[/tex]
We must assure the law of conservation of mass is respected, so we equal the number of atoms at each side of the equation by adding the stoichiometric coefficients to the left of each compound as shown below:
[tex]H_3PO_4 (aq) + 3NaOH (aq) \rightarrow 3H_2O (l) + Na_3PO_4 (aq)[/tex]
So the coefficients are 1, 3, 3 and 1 respectively for each species in the chemical reaction.
Regards.
a. Which date shows a waning crescent?
Answer:
Warning means that it is getting smaller while crescent refers to the crurved shape simular to a banana or a boat. The warning crescent moon rises after midnight and is still up and visible in the morning and day sky before itsets in the afternoon.
Explanation:
What disease is spread through warm climates ?
Answer:
malaria
Explanation:
The U.S. Food and Drug Administration (FDA) recommends that an adult consume less than 1.8 g
of sodium per day.
What mass of sodium chloride (in grams) can you consume and still be within the FDA guidelines? Sodium chloride is 39% sodium by mass
Answer:
less than 4.62 g
Explanation:
Sodium chloride contains 39% sodium by mass. Hence, 1 g of sodium chloride will contain:
39/100 x 1 = 0.39 g of sodium.
If 1 g of sodium chloride contains 0.39 g of sodium, then how many g of sodium chloride will contain the 1.8 g required sodium per day?
1 g sodium chloride = 0.39 g sodium
x g sodium chloride = 1.8 g sodium
x = 1.8 x 1/0.39 = 4.62 g of sodium chloride
Since the adult is supposed to consume less than 1.8 g of sodium per day, the mass of sodium that should be consume per day and still be within the FDA guidelines will be less than 4.62 g of sodium chloride.
What are two things plants have which animal cells do not
Answer:
Animal cells don't have a dividing cell wall like plant cells do
Explanation:
Plants cells use photosynthesis from the sun, which requires them to have chloroplast filled with chlorophyll to complete this function; animal cells do not have chloroplasts