Answer: a. False.
b. True
c. False
Explanation:
a. When a solution is made, the enthalpy of mixing is always a positive number.
This is false. It should be noted that the nature of reaction determine the enthalpy which can either be positive or can be negative.
b. An increase in entropy favors mixing.
This is true because when molecules get randomly distributed, they mix with one another. Therefore, an increase in entropy favors mixing.
c. A solute will dissolve in a solvent if solute-solute interactions are stronger than solute-solvent interactions.
This is false. This is because the solute-solute interactions have to be weaker and not stronger.
a. When a solution is made, the enthalpy of mixing is always a positive number. FALSE
b. An increase in entropy favors mixing. TRUE
c. A solute will dissolve in a solvent if solute-solute interactions are stronger than solute-solvent interactions. FALSE
EntropyEntropy is the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work
EntalphyEnthalpy is the sum of the system's internal energy and the product of its pressure and volume.
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I am running a reaction that creates 138 grams of sulfur trioxide (S03). My theoretical yield was 156 grams. What is my percentage yield?
Answer:
88.46%
Explanation:
Percentage yield is actual/theoretical * 100
138/156 * 100 = 88.4615385
can someone help me?
Answer:
no, and next time take it right
Explanation:
1.
How many miles per hour is 30.5 m/s?
Answer:
68.22656
Explanation:
I think this is the answer.
Hope it's correct!
Answer:
68.22656
Explanation:
Speed
30.500001382
Meter per second
=
68.22656
Miles per hour
Formula
multiply the speed value by 2.237
(hope this helps can i plz have brainlist :D hehe)
How many molecules are in 2.50 moles of carbon dioxide?
Question 3 options:
1.5055 molecules
4.15 x 10^24 molecules
1.5055 x 10^24 molecules
2.4 x 10^24 molecules
Answer:
1.5055×10²⁴ molecules
Explanation:
From the question given above, the following data were obtained:
Number of mole CO₂ = 2.5 moles
Number of molecules CO₂ =?
The number of molecules present in 2.5 moles CO₂ can be obtained as:
From Avogadro's hypothesis,
1 mole of CO₂ = 6.022×10²³ molecules
Therefore,
2.5 mole of CO₂ = 2.5 × 6.022×10²³
2.5 mole of CO₂ = 1.5055×10²⁴ molecules
Thus, 1.5055×10²⁴ molecules are present in 2.5 moles CO₂
The reaction Fe3O4 +C ---> CO2 + Fe can be balanced with the coefficients:
1,4,4,3
2.4.4.3
1,2,2,3
O 1,1,1,3
Answer:
the answer is 1,2,2,3
Explanation:
Fe3O4 +C ---> CO2 + Fe
1Fe3O4 +2C ---> 2CO2 + 3Fe
Help plz :( Convert 48,000 seconds into hours. (Two step problem, use two conversion factors in a row)
Answer:
13.3 h
Explanation:
Step 1: Given data
Time (t): 48,000 seconds
Step 2: Convert "t" from seconds to minutes
We will use the conversion factor 1 min = 60 s.
48,000 s × 1 min/60 s = 800 min
Step 3: Convert "t" from minutes to hours
We will use the conversion factor 1 h = 60 min.
800 min × 1 h/60 min = 13.3 h
To sum up, 48,000 seconds is equal to 13.3 hours.
Two colorless chemicals combine inside a glow
stick. When the chemicals combine, they produce
brightly colored light. The glow stick's temperature
does not change.
emission of heat
emission of light
color change
formation of gas
Answer:
Option B & Option C
Explanation:
correct on edge! :D
When chemicals combine chemical change takes place which is accompanied by emission of heat and light.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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Which is a typical characteristic of an ionic compound?
A) Electron pairs are shared among atoms.
B) The ionic compound is a discrete molecule that can be represented in a Lewis Structure.
C) An ionic bond is one of the weakest attractive forces that results in ionic compounds having low
melting points.
D) The ionic compound is a continuous array of repeating unit cells that comprises a crystalline structure.
Answer:
The answer to this problem is C
1. How many moles are in an 84.2 g sample of aluminum sulfate?
Answer:
0.246 moles
Explanation:
Aluminum Sulfate is an ionic equation so we need to write the equation first with proper charges and subscripts:
Aluminum (Al) has a charge of [3+]. Sulfate (SO4) has a charge of [2-]. The charges need to be swapped to match.The ionic equation therefore is: Al_2(SO4)_3. We need 2 Aluminum's to match with the charge of 3 sulfates.Now that we know the ionic equation, we need to find the molar mass of Al_2(SO4)_3. There's 2 Aluminum's, each weighing 26.98 g/mol. There are 3 sulfates, each sulfate weighs 96.06 g/mol. We need to multiply the number of elements/compounds by their mass to get the total molar mass and then add them up (remember atomic mass = molar mass in g/mol):
(2 Al * 26.98 g/mol) + (3 (SO4) * 96.06 g/mol) = 342.15 g/mol of Al_2(SO4)_3We now know the molar mass of Al_2(SO4)_3 we need to find how many moles of it there are in an 84.2g sample. To do that, we need to do some dimensional analysis:
84.2g Al_2(SO4)_3 * ( 1 mol of Al_2(SO4)_3 / 342.15 g/mol of Al_2(SO4)_3 )The grams of Al_2(SO4)_3 cancel so that we're left with moles of Al_2(SO4)_3 on top:
84.2 * ( 1 mol of Al_2(SO4)_3 / 342.15 ) = 0.246 mol of Al_2(SO4)_3So in an 84.2g sample of Al_2(SO4)_3 (aka aluminum sulfate), there are 0.246 moles. This is correct because in one mole of Al_2(SO4)_3, there are 342.15g and the sample of 84.2 g of Al_2(SO4)_3 is way smaller than that, so our answer should be less than one mole, which it is.
I hope this helped!
1. How many moles are in the following: a. 5 grams of Lici
Answer:
Number of moles = 0.1179 (Approx)
Explanation:
Given:
Mass of LiCl = 5 grams
Molar mass of LiCl = 42.39 g
Find:
Number of moles
Computation:
Number of moles = Mass / Molar mass
Number of moles = 5 / 42.39
Number of moles = 0.1179 (Approx)
In a chemical reaction, reactants interact to form products. This process is summarized by a chemical equation. In the Balancing Chemical Equations Gizmo, look at the floating molecules below the initial reaction: H2 + O2 ???? H2O. 1. How many atoms are in a hydrogen molecule (H2)? 2. How many atoms are in an oxygen molecule (O2)? 3. How many hydrogen and oxygen atoms are in a water molecule (H2O)? 4. In general, what does a subscript (such as the "2" in H2) tell you about the molecule? 5. A chemical equation is balanced if the number of each type of atom on the left side is equal to the number of each type on the right side. Is this reaction balanced?
Answer:
See answer below
Explanation:
Let's write the equation again:
H₂ + O₂ ---------> H₂O
Now that we have written the equation, let's solve the exercise:
1. In this case, we first need to make a difference between atom and molecule. An atom is just a single element, a molecule it's when you have more than 1 element in a compound.
Knowing this, we have the H₂. In this case we only have one element, Hydrogen. However, as you can see in the expression, we have a number 2 as a subscript. The number 2 means that the hydrogen it's not alone, we do not have one hydrogen, we have two hydrogens, therefore, it becomes a molecule. Now, This molecule, according to the number 2 as subscript, means that the molecule of hydrogen have 2 atoms of hydrogens, and this formed the molecule, therefore, there are 2 atoms of hydrogens in H₂.
2. Following the same explanation of above, but using oxygen, we have the same thing, so, in a molecule of O₂, we have 2 atoms of oxygen.
3. The molecule of water is composed of Hydrogen and oxygen. As you can see, in this case we have 2 hydrogen and 1 oxygen, therefore, in 1 molecule of water, there are 1 atom of oxygen and 2 atoms of hydrogen.
4. The subscript, as you may know now, tell us the number of atoms that you have in a molecule or compound. This number also means, in different compounds the oxidation state of the atoms that conform the molecule.
5. No, the equation is not balanced, because we do not have the same number of oxygen on the side of the products. We need to balance that. As the oxygen is unbalanced, we just need to put numbers as coefficients, behind the molecule. This number will multiply the number of atoms of the referred molecule. So, doing this with the water on the products to equal the number of oxygen, we have:
H₂ + O₂ ---------> 2H₂O
But this 2, unbalance at the same time the number of hydrogens. We now have 4 hydrogens in the product, so, to balance this, we put a 2 on the reactants:
2H₂ + O₂ ---------> 2H₂O
Now the reaction is balanced.
Hope this helps
1. Give examples of a catalyst and the reaction it catalyses.
1
Answer:
Explanation:
Iron Haber process = (making ammonia)
Vanadium (V) oxide = Contact process (a stage in making sulfuric acid)
Manganese dioxide = Decomposition of hydrogen peroxide (produces water and oxygen)
Consider an experimental setup with two compartments separated by a phospholipid bilayer membrane containing ion channels selectively permeable only to chloride ions. The left compartment (also called inside) contains 1 mM Cl- and the right compartment (also called outside) contains 100 mM Cl-. What will the electrical potential be when the system attains equilibrium
This question is incomplete, the complete question is;
Consider an experimental setup with two compartments separated by a phospholipid bilayer membrane containing ion channels selectively permeable only to chloride ions. The left compartment (also called inside) contains 1 mM Cl- and the right compartment (also called outside) contains 100 mM Cl-. What will the electrical potential be when the system attains equilibrium? [ assume body temperature; log 100 = 2, log 10 = 1, log 1 = 0, log 0.1 = -1, log 0.01 = -2]
Options;
a) -62 mV
b) -124 mV
c) +62 mV
d) 0 mV
e) +124 mV
Answer:
the electrical potential be when the system attains equilibrium is –124mV
Option b) –124mV is the correct answer
Explanation:
Given the data in the question;
Two compartments are divided by lipid bilayer;
In inside compartment Cl- ion concentration- 1mM and out side of the cell concentration is 100mM
now we apply the Nernst equilibrium potential equation;
Chlorine ion valency is z = –1
So
[tex]E_{eq}[/tex] = 62/z × log(ion outside/ ion inside) [for Cl‐ ions]
[tex]E_{eq}[/tex] = (62 / –1) x log( 100 / 1 )
[tex]E_{eq}[/tex] = -62 x 2 =
[tex]E_{eq}[/tex] = –124mV
Therefore, the electrical potential be when the system attains equilibrium is –124mV
Option b) –124mV is the correct answer
A chemical reaction takes place inside a flask submerged in a water bath. The water bath contains 8.10kg of water at 33.9 degrees celsius . During the reaction 69.0kJ of heat flows out of the bath and into the flask.Calculate the new temperature of the water bath.
Answer: The new temperature of the water bath is [tex]31.9^0C[/tex]
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
[tex]Q=m\times c\times \Delta T[/tex]
Q = Heat released by water =[tex]69.0kJ=69000J[/tex] (1kJ=1000J)
m= mass of water = 8.10 kg= 8100 g (1kg=1000g)
c = specific heat capacity = [tex]4.184J/g^0C[/tex]
Initial temperature of the water = [tex]T_i[/tex] = [tex]33.9^0C[/tex]
Final temperature of the water = [tex]T_f[/tex] = ?
Change in temperature ,[tex]\Delta T=T_f-T_i[/tex]
Putting in the values, we get:
[tex]-69000J=8100g\times 4.184J/g^0C\times (T_f-33.9)^0C[/tex]
[tex]T_f=31.9^0C[/tex]
The new temperature of the water bath is [tex]31.9^0C[/tex]
How many molecules in 4.10 mol H2O?
6.02×10^23
1.4×10^23
2.47×10^24
1.15×10^-23
Answer:
2,47 * [tex]10^{24}[/tex] (molecules)
Explanation:
Avogadro's number is a very important relationship: 1 mole = 6,02 * [tex]10^{23}[/tex] atoms, molecules, protons, etc.
To convert from moles to molecules, multiply the molar amount by Avogadro's number.
4,1 mol * 6,02 * [tex]10^{23}[/tex] ≈ 24,7 * [tex]10^{23}[/tex] = 2,47 * [tex]10^{24}[/tex] (molecules)
Therefore the third answer is correct
One mole of a metallic oxide reacts with one mole of hydrogen to produce two moles of the pure metal
and one mole of water. 5.00 g of the metallic oxide produces 2.32 g of the metal. What is the metallic
oxide? (Use molar masses)
Answer:
The metallic oxide is Li₂O
Explanation:
Let the metallic oxide be M₂O
Thus;
M₂O + H₂ = 2M + H₂O
Molar mass of M₂O = (2x + 16)
We assume Molar mass of M to be x.
We are told that 5.00 g of the metallic oxide produces 2.32 g of the metal.
By proportion, we can write the following;
5g of M₂O × (1 mole of M₂O/(2x + 16)) × (2 moles of M/1 mole of M₂O) = 2.32 g of M × 1 mole of M/x g of M
This cancels out to give us;
10/(2x + 16) = 2.32/x
Cross multiply to get;
10x = 2.32(2x + 16)
10x = 4.64x + 37.12
10x - 4.64x = 37.12
5.36x = 37.12
x = 37.12/5.36
x = 6.925 g/mol
The metal with a molar mass closest to this value of x is Lithium which has a molar mass of 6.94 g/mol
Thus the metal is Lithium and as such the metallic oxide is Li₂O
The ______ are new substances taht are created following a chemical reaction?
A simplified version of photosynthesis can be represented as carbon dioxide
combining with water to form glucose and oxygen: 6CO2 + 6H20 - C6H12O6 +
602. In this reaction, is oxidized.
A) hydrogen
B)
oxygen
C) carbon dioxide
D) carbon
B) oxygen is oxidized.
Further explanationGiven
photosynthesis reaction
6CO2 + 6H20 ⇒ C6H12O6 + 602
Required
the oxidation compound
Solution
Oxidation-reduction reactions or abbreviated as Redox are chemical reactions in which there is a change in oxidation number
Oxidation is an increase in oxidation number, whereas Reduction is a decrease in oxidation number.
In the photosynthetic reaction, oxidation and reduction reactions occur in:
CO2 to C6H12O6 : reduction
Oxidation number of C from +4 to 0
H2O to O2 : oxidation
Oxidation number of O from -2 to 0
A 980 pound horse is diagnosed with strongyle parasites. The veterinarian orders he be given 10 milligrams per kilogram of de-wormer. How many milligrams will he need?
What would the volume of a gas be at -125°C, if it had a volume of 693 mL at 45°? A -1,925 mL b. 322.5 mL c. 2,279 mL d. 15.4 mL
Answer: b. 322.5 mL
Explanation:assume constant pressure, then
693/(273.15+45) = v/(273.15-125)
v= 693*148.15/318.15 = 322.7
By using Charles law, the volume will be 322.5 mL
What is Charle's law?
The volume of such an ideal gas is proportional to its absolute temperature at constant pressure, according to Charles' law.
According to Charles law.
[tex]T_{1} / T_{2} = V_{1} / V_{2}[/tex]
where, T is temperature and V is volume.
What is volume?A substance or object's volume refers to the amount of 3D space it takes up.
Calculation of volume.
Given data:
V = 693 mL
[tex]T_{1}[/tex] =-125°C = (273-125) = 148 K
[tex]T_{2}[/tex] = 45° = (273+45) = 318 K
Put the value of given data in Charles law formula.
148 K/ 318 K = V / 693 mL
V = 322.5 mL.
Therefore, by using Charles law the volume of a gas will be 322.5 mL.
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A powder sample weighing 250 g and having a surface area of 1 m2/g is dispersed in 1 L of water. After 10 minutes, 0.4 g of the sample is dissolved. The aqueous solubility of the sample is 0.01 g/cm3. a) Calculate k. Assume that sink conditions are prevailing and that the surface area of the sample is constant. b) How long will the sink conditions prevail
Answer:
a)
[tex]K = 2.64 * 10^{-8}[/tex]
b)
[tex]15 \frac{5}{8}[/tex] hours
Explanation:
Given
Surface Area (S) of 250 grams of powder sample [tex]= 250[/tex] square meter.
[tex]S = 2500000[/tex] square centimeter
[tex]V\frac{dC}{dT} = 0.40[/tex] grams/minute
[tex]V\frac{dC}{dT} = \frac{dM}{dT} = \frac{0.40*60}{10} = 0.66[/tex] mg per second
[tex]C_s = 0.01[/tex] gram per cubic meter [tex]= 10[/tex] mg/ml
a)
[tex]\frac{dM}{dT} = K SC_s[/tex]
[tex]0.66 = K* 2500000* 10\\[/tex]
[tex]K = 2.64 * 10^{-8}[/tex] cm /sec
b) Time taken
Time taken to sink
[tex]\frac{10*60}{0.4} * 37.5 = 56,250[/tex]
Time in hours
[tex]15 \frac{5}{8}[/tex] hours
1.5 pts) The Rf value of compound A is 0.29 when developed in petroleum either and 0.44 when developed in dichloromethane. Compound B has an Rf value of 0.45 in petroleum either and 0.69 in dichloromethane. Which solvent would be better for separating a mixture of compounds A and B. Briefly explain your choice. What is petroleum ether
Answer:
The better solvent for separating the mixture of A and B is dichloromethane
Explanation:
Petroleum ether is the mixture of hydrocarbons obtained from the petroleum distillation with a boiling range between 35 and 60°C. Is used as a solvent.
In the other hand, the best solvent for separating a mixture in TLC is the one that has the higher difference between RF's of the compounds.
The difference in RF's in dichloromethane is:
|0.44 - 0.69| = 0.25
In petroleum ether:
|0.29 - 0.45| = 0.16
That means the better solvent for separating the mixture of A and B is dichloromethane
Aluminum reacts with iron nitrate to form aluminum nitrate and iron. What is the
reactant, or what are the reactants, in this chemical equation?
aluminum nitrate
aluminum nitrate and iron
iron and aluminum
aluminum and iron nitrate
When Robert Hooke looked at cork through a microscope , he named what he saw “cells” because__________
a. He could barely see what he was looking at
b. The cork looked like shells
c. They were the holes of the cork
d. The cork looked like tiny rectangular rooms
Answer:
D. The cork looked like tiny rectangular rooms
Explanation:
The invention that helped scientists discover the cell is the microscope. Tell why Hooke called the structures he saw in the cork cellular("small rooms"). He called them cellular because the box like cells reminded him of the monks monasteries.
Which of the following represents C3H8?
Among the given options the compound with the formula C₃H₈ is option C. It is an organic compound under named as propane.
What is propane?
Propane is an organic compound classified as a hydrocarbon with saturated carbon - hydrogen bonds. It's formula is C₃H₈. It contains 3 carbons and 8 hydrogens.
The two end carbons contains 3 hydrogens each and the middle carbon contains 2 hydrogens. They are all bonded through sigma bonding. The compound in A is C₅H₁₂ and in B, it is C₆H₁₄.
The formula of the compound in option D is C₅H₁₀. Hence, the skeleton showing the compound with the formula of C₃H₈ is option C.
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convert
chloroethane
into enene
What is Kb for N2H4 if the pH of a 0.158M solution of N2H5Cl is 4.5?
Answer:
Kb[tex]= 1.58 * 10^{-6}[/tex]
Explanation:
The correct question is
What is Kb for N2H4 if the pH of a 0.158M solution of N2H5Cl is 4.5?
Solution-
N2H4Cl hydrolyses on addition of water
The reaction equation is as follows -
N2H4+ + H2O ----> N2H4 + H3O+
[tex]Ka = \frac{K_w}{K_b} = \frac{10^{-14}}{K_b}[/tex]
pH [tex]= 4.5[/tex]
[tex][H+] = 10^{-pH} = 10^{-4.5}[/tex]
[tex]K_b= \frac{10^{-14} }{K_b} = \frac{Y_2}{0.158} \\K_b= \frac{(10^{-4.5})^2}{0.158}\\=> Kb = 0.158 * 10-14 /(10-4.5)2[/tex]
Kb[tex]= 1.58 * 10^{-6}[/tex]
19. Which wind water interaction is responsible for cycling nutrient-rich waters
from the ocean floor to the sea surface?
A. upwelling
B.storm surge
C.downwelling
D.surface currents
Explanation:
ksiiaisisjjsjajajhahajajjalañLzlzl
Explanation: A . upwelling .
Gizmo Warm-up In a chemical reaction, reactants interact to form products. This process is summarized by a chemical equation. In the Balancing Chemical Equations Gizmo, look at the floating molecules below the initial reaction: H2 O2 ---> H2O. How many atoms are in a hydrogen molecule (H2)
Answer:
There are two atoms in one hydrogen molecule.
Explanation:
Hello!
In this case, when going over chemical reactions, we need to realize about the amount of atoms of each element; thus, according to the given chemical reaction by which water is formed:
[tex]H_2+O_2\rightarrow H_2O[/tex]
It is seen there are two hydrogen atoms in the hydrogen molecule, two in oxygen and two hydrogen atoms and one oxygen atom in water; however, these reactions must be balanced according to the law of conservation of mass:
[tex]2H_2+O_2\rightarrow 2H_2O[/tex]
Which means we have two hydrogen molecules with two atoms each, one oxygen molecule with two atoms and two water molecules with two hydrogen atoms and one oxygen atom each.
Best regards!
After two half-lives, how much of the original material has decayed? 25 percent 50 percent 75 percent 100 percent
The original material has decayed 75%
Further explanationGiven
two half-life
Required
The decayed sample
Solution
General formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
t = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
t = 2 x t 1/2
Input the value :
[tex]\tt \dfrac{Nt}{No}=\dfrac{1}{2}^2=\dfrac{1}{4}=25\%[/tex]
The amount of Nt = 25% No