1. Moles
a. Which has more mass, 1 g of C or 1 g of Pb?
b. Which has more mass, I mole of C or 1 mole of Pb?
c. How much mass does a mole of C have, and where do you find this information?
d. How much mass does a mole of Pb have?
e. How many atoms does a mole of C have?
f. How many atoms does a mole of Pb have?
g. Does a mole of any element have more atoms than a mole of another element?
h. If a mole of C has the same number of atoms as a mole of Pb, why is a mole of Pb so much heavier than a mole of C?
i. How many molecules of CH4 are in a mole of CH4?
j. What is the mass of a mole of CH4?
k. How many H atoms are in 1 molecule of CH4?
l. How many moles of H atoms are in 1 mole of CH4?
In: Chemistry
Given the data tables below for the concentrations of crystal violet dye in the crystal violet-hydroxide reaction CV+ + NaOH- --> CVOH + Na, calculate the order of hydroxide if the order of crystal violet is first order (ln[A] shows a linear relationship for CV).
CV+ + OH- --> CVOH
Data
|
Trial 1: CV + 0.020M NaOH |
||||
|
Time (s) |
%TCV |
[A]CV |
ln[A]CV |
1/[A]CV |
|
190 |
49.8 |
0.303 |
-1.195 |
3.303 |
|
250 |
52.6 |
0.279 |
-1.276 |
3.584 |
|
310 |
55.8 |
0.253 |
-1.373 |
3.947 |
|
370 |
58.4 |
0.234 |
-1.454 |
4.281 |
|
430 |
61.2 |
0.213 |
-1.545 |
4.689 |
|
490 |
63.8 |
0.195 |
-1.634 |
5.123 |
|
Trial 2: CV + 0.040M NaOH |
||||
|
Time (s) |
%TCV |
[A]CV |
ln[A]CV |
1/[A]CV |
|
180 |
54.8 |
0.261 |
-1.342 |
3.828 |
|
240 |
59.6 |
0.225 |
-1.493 |
4.449 |
|
300 |
64.2 |
0.192 |
-1.648 |
5.196 |
|
360 |
68.4 |
0.165 |
-1.802 |
6.063 |
|
420 |
72.2 |
0.141 |
-1.956 |
7.069 |
|
480 |
75.8 |
0.120 |
-2.118 |
8.310 |
In: Chemistry
Consider each of the following ideal geometries for MXn molecules (n = 3-6) and thte distortions described for each. What are the point groups of the ideal geometries and the distorted geometries? 11. MX3 trigonal planar distorted by lifting the M atom out of the plane.
12. MX4 tetrahedral distorted by slightly flattening the molecule along on of the C2 axes.
13. MX5 trigonal bipyramid distorted by equally elongating the two axial bonds.
14. MX6 octahedral distorted by slightly closing the 90º angles between the three M-X bonds in both sets of the cis-related positions.
15. MX6 trigonal prism distorted by a 45º rotation of one of the triangular faces.
In: Chemistry
In an experiment, why would the concentration of a sample decrease when changing the wavelength for a spectrophotometer from 235 nm to 280 nm?
In: Chemistry
A mixture of LiAlH4 and LiCl weighs 7.51 g. LiAlH4 reacts exothermically with ethanol according to the following equation LiAlH4(s) + 4CH3CH2OH(l) → Li[Al(OC2H5)4](s) + 4H2
14.48 g of Li[Al(OC2H5)4] is formed when this sample is dissolved in CH3CH2OH, what percentage of the original sample is LiAlH4, also what percentage is LiCl? Assuming LiAlH4 is completely turned into Li[Al(OC2H5)4] and LiCl dissolves in ethanol
In: Chemistry
A galvanic cell consists of a standard hydrogen electrode and a copper electrode. Suppose that the copper electrode is immersed in a solution that is 0.1 M NaOH and that it is saturated with Cu(OH)2. Find the cell potential?
In: Chemistry
If 15.0 mL of a 1.5M HCl solution at 21.50C is mixed with 25.0mL of a 1.5M NaOH solution at 21.50C that is in a calorimeter, and the final mixed solution temperature rises to28.50C, what is the ΔHrxnfor this process?Assume that Ccalorimeter= 35.5J/0C.
a.What is the balanced equation for the reaction?
b.What is the source of the heat that is causing the increase in temperature?
c.Calculate the amount of heat absorbed or lost for the HCl/NaOH solution. Assume aqueous conditions.(Cwater= 4.18 J/g·0C, d =1.0 g/mL)
d.Calculate the amount of heat absorbed or lost by the calorimeter. The calorimeter’s initial temperature is the same as the solution that is initially inside it.
e.Determine the amount of heat absorbed or lost during this reaction.
f.Which of the reactants is the limiting reagent? Determine the moles of the limiting reagent.
g.Determine the amount of heat given off per mole of limiting reagent(ΔHrxn).Make sure to include an appropriate sign indicating whether it is an endothermic (+) or exothermic (-) process. Provide your answer in units of kJ/mol.
In: Chemistry
You added 20 mL of 0.20M solution of Ba(OH)2(aq) to 50 mL of 0.10M solution of HCl(aq). The pH of the resulting solution is ________.
In: Chemistry
The standard enthalpy change for the following reaction is -170 kJ at 298 K. 2 Cu(s) + 1/2 O2(g) Cu2O(s) ΔH° = -170 kJ What is the standard enthalpy change for the reaction at 298 K? 4 Cu(s) + O2(g) 2 Cu2O(s)
A student determines the heat of dissolution of solid cobalt(II) chloride using a coffee-cup calorimeter of negligible heat capacity. When 1.33 g of CoCl2(s) is dissolved in 111.00 g of water, the temperature of the solution increases from 25.00 to 26.84 °C. Based on the student's observation, calculate the enthalpy of dissolution of CoCl2(s) in kJ/mol. Assume the specific heat of the solution is 4.184 J/g°C.
In: Chemistry
balance the following oxidation reduction in an acidic solution Cl2(g) = Cl– (aq) + OCl–(aq)
(hint: this reaction is a disproportionation, meaning the same element undergoes both oxidation and reduction. Use Cl2 as the reactant for each of your half reactions)
Please explain. Thank you!
In: Chemistry
Describe and justify the optimal type/amount of carbohydrate consumption for various times related to exercise (pre-, during-, post-)
In: Chemistry
- Minimum 2 pages
- Topic: Scientific discovery/development relating to chemistry (no more than 3 years ago)
Paper should cosnsist of:
- Brief summary of the topic
- Why it is important (why you chose it)
- How it will affect society (positively/negatively)
Please, give me a hand for this paper. I can not find the topic at all, and it's hard to cauth the points up.
The due date is until Thursday.
In: Chemistry
What are resistant starches/carbohydrates? Why are they considered a ‘good’ carbohydrate? Would they be good to consume during exercise? After? Explain. What is retrogradation?
In: Chemistry
|
Heat of Vaporization and Heat of Fusion Learning Goal: To calculate the total energy required to convert a solid to a gas using heat capacity, heat of fusion, and heat of vaporization. The amount of heat required to melt one mole of a solid is called the heat of fusion (ΔHfus). The amount of heat required to vaporize (boil) one mole of a liquid is called the heat of vaporization (ΔHvap). The heat of fusion and the heat of vaporization can be used to calculate the amount of heat needed to melt or vaporize, respectively, a given amount of substance.For example, the heat of fusion for H2O is 6.02 kJ/mol, which means that 6.02 kJ of heat is needed to melt a mole of ice. Twice as much heat is needed to melt twice as much ice, as shown here: 2.00 mol×6.02 kJ/mol=12.0 kJ |
Constants Heat of fusion (ΔHfus) is used for calculations involving a phase change between solid and liquid, with no temperature change. For H2O, ΔHfus=6.02 kJ/mol. Specific heat capacity (C) is used for calculations that involve a temperature change, but no phase change. For liquid water, C=4.184 J/(g⋅∘C). Heat of vaporization (ΔHvap) is used for calculations involving a phase change between liquid and gas, with no temperature change. For H2O, ΔHvap=40.7 kJ/mol. Part A How much heat is required to melt 52.5 g of ice at its melting point? Express your answer numerically in kilojoules.
SubmitHintsMy AnswersGive UpReview Part Correct Part B How much heat is required to raise the temperature of 52.5 g of water from its melting point to its boiling point? Express your answer numerically in kilojoules.
SubmitHintsMy AnswersGive UpReview Part Incorrect; Try Again; 4 attempts remaining; no points deducted ****NEED HELP PLEASE PART B ANSWER IS WRONG**** |
In: Chemistry
Every time the compound is contaminated the melting range will go up.
Group of answer choices
True
False
In: Chemistry