A physical change is a change
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20-20=X what is X? I don't know please help me
Water pollution that washes into storm sewers from many places, such as parking lots and lawns, is known as nonpoint-source pollution. True or false ?
Water is moving across a membrane from solution a into solutionb. What can be inferred? Solution a must be pure water. Solution a must have a lower solute concentration than solutionb. Solution a must have a higher solute concentration than solutionb. Solution a and solution b must have the same concentration of solutes. Solution b must be pure water.
1) Look at the graph. What is the independent variable and the dependent variable?
The part I cannot figure out is the question afterwards which is If the calorimeter has a heat capacity of 8.20 J/°C and a correction is included to account for the heat absorbed by the calorimeter what is the heat of reaction q
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Answer:
a. qrxn = 831 J
b. 863 J
Explanation:
we know that density is the mass of a substance per unit volume
d=mass/volume
the volume of the solution is the combination of solution A and solution B
1.02 g/mL=mass/(25+25)
mass=50*1.02
mass=51g
Recall that Q=mCdT
mass=m, C=specific heat capacity
dT=change in temperature
qrxn = (51 g)(4.18 J/g⋅°C)(25.3 °C - 21.4 °C)
qrxn = 831 J
2.Heat=Heat capacity *change in temperature
qcal = (8.20 J/°C)((25.3 °C - 21.4 °C)
qcal = 31.98 J
qrxni + qcal = qrxn
qrxn = 831 J + 32.0 J
863 J------Heat of reaction
863 J =(51 g)(Heat Capacity)(25.3 °C - 21.4 °C)
4.34 J/g⋅°C
q = cΔT
Now, just plug in the ΔT we had for the original equation (which was 3.9) and use the specific heat of the calorimeter to get q.
q = (8.20) * (3.9)
q = 31.98, or about 32
The 32 is what was absorbed by the calorimeter, so we can add that to the original value to get our answer.
831 + 32 = 863 J
So, the answer is 863 J
Hope this helped!! :D
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Answer:
I got you..you need help but with which question?
Explanation:
Have a great day!
B ratio that describes the amount of solvent or solution divided by the amount of solute
C ratio that describes the mass of solute divided by the mass of solvent
D ratio that describes the amount of solvent in a solution
2 Which contributes to the dissolution of sugar in water?
A the dissociation of an ionic compound in water
B a strong pull of water molecules on an ionic compound
C the dissociation of a polar covalent compound in water
D a strong pull of water molecules on a polar covalent compound
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These are two questions and two answers.
Question 1: Which best defines concentration?
Answer: option A, ratio that describes the amount of solute divided by the amount of solvent or solution
Explanation:
There are many different measures of concentration: percent, molarity, molality, mole fraction are some examples.
All of them express the ratio of solute to solvent or solution, in different kind of units, may be mass, number of moles, or volume.
Molarity is number of moles of solute per liter of solution. Molality is number of moles of solute per kg of solvent.
So, as you see it is always a ratio of the amound of solute, but it is not a fixed unit.
Question 2. Which contributes to the dissolution of sugar in water?
Answer: option D, a strong pull of water molecules on a polar covalent compound.
Explanation:
Sugar is not a ionic compound so it does not dissociate.
Sugar is a molecule, so it remains as such in solution.
Sugar is polar, so it can be dissolved in water that is a polar solvent (like dissolve like, is the rule).
The dissolution is explained by the fact that the pull exerted by the molecultes of solvent on the molecules of solute, is greater than the pull that the molecules of solute extert among themselves.
That permits the molecules of solvent surround the molecules of solute and get them appart of the solid substance to form the aqueous solution.
Concentration is the ratio that describes the amount of solute divided by the amount of solvent or solution; option A
The dissociation of sugar in water is due to a strong pull of water molecules on a polar covalent compound; option D
What is concentration of a solution?
Concentration of a solution is the amount of solute present in a given volume of solution.
Thus, concentration is the ratio that describes the amount of solute divided by the amount of solvent or solution.
The dissolution of sugar in water forms a sugar solution.
Sugar is a polar covalent molecule. The dissociation of sugar in water is due to a strong pull of water molecules on a polar covalent compound.
Learn more about polar compounds at: brainly.com/question/1433127
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The answer is D. have nausea and hair loss.
b. O
c. He
d. Mg
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Considering the definition of molar mass, the number of moles of chlorine present in 140 grams of chlorine gas is 1.975 moles.
Definition of molar mass
The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.
Number of moles present in 140 g of Cl₂
Next, you can apply the following rule of three: If by definition of molar mass 70.9 grams are contained in 1 mole of Cl₂, 140 grams of the gas are contained in how many moles?
amount of moles= 1.975 moles
Finally, the number of moles of chlorine present in 140 grams of chlorine gas is 1.975 moles.
Learn more about molar mass:
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