The formula for methane is CH4 and it’s molar mass is 16.04 grams/mol.
(a) How many moles of methane are in 2.750 grams of methane?
(b) How many molecules of methane are in a 11.5 mole sample?
In: Chemistry
Why is it not necessary to test the reactivity of the elemental metals with solutions of the same metal ion? To illustrate your explanation, write the equation for the potential chemical reaction using one of the metals: Cu, Zn, Mg, Ni, Pb.
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Now that Hermione understands empirical formulas she wants to teach Harry and Ron. What is the empirical formula for dibromoethane: C2H4Br2
A. CH2Br2
B. CH2Br
C. C2H4Br
D. CHBr
E. C2H2Br2
2.Calculate the maass percent composition of carbon in C2H5Cl.
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5. Describe qualitatively the microstructural development that will occur upon slow cooling from of 1050 steel from 1600 °C to 20 °C.
6.
a). What are p-type semiconductors? What are their differences comparing with n-type semiconductors?
b). Moore’s law predicts the rapid and steady growth in the number of transistors contained on a single microcircuit chip. Why do engineers want to increase the number of transistors contained on a single microcircuit chip?
c). Even through silicon is abundant on the earth. What is the key reason that silicon wafers are so expensive?
d). Based on the semiconductor introduction video, if the thickness of a semiconductor wafer is ___ _ floor height, the Integrated Circuits are build on the top ____ floor(s).
7.
a). Among multiple components of a composite material, at least two components have to serve for specific functions. What are these two components? What are these two specific function?
b). Give an example of engineering application (not household items), where ceramics will be good materials to choose and high alloy steel will not be a good material to choose. Explain your reasons.
c). Give an example of engineering application (not household items), where polymers will be good materials to choose and composites will not be a good material to choose. Explain your reasons.
8.
a). Among many polymer processes, which processes can be usefor thermoplastics? Can they be used to process thermosetting polymers? Explain your reasons.
b). Engineering designers select thermosetting polymers to make electrical components. Explain why not use thermoplastic polymers.
c). PVC popes are widely used in commercial and residential construction, what does PVC stands for?
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The solubility product for barium sulfate is 1.1*10^-10. Calculate the molar solubility of barium sulfate.
1) 5.5*10^-11 mol/L
2) 1.1 *10^-5 mol/L
3) 2.1*10^-5 mol/L
4) 1.1*10^-10 mol/L
5) 2.2*10^-10 mol/L
I don't understand how to solve this. I'm stuck. Can anyone help me soon as possible as fast? Thank you.
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Calculate the pH, pOH, [H3O+], and [OH-] of the following
solutions:
(a) 0.001 M HNO3,
(b) 0.3 M Ca(OH)2;
(c) 3.0 M HNO3,
(d) 6.0 M NaOH,
(e) 0.05 M HBr
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Experimental measurement shows that 0.200 M arsenious acid, H2AsO3 (aq), is 0.0051% dissociated at 25 degrees Celsius. Determine the value of the acid-dissociation constant of H2AsO3 (aq) at 25 degrees Celsius.
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briefly explain how ion exchange chromatography works. Why is the pH of the elutent changed during the seperation?
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When solutions of silver nitrate and calcium chloride are mixed, silver chloride precipitates out of solution according to the equation
2AgNO3(aq)+CaCl2(aq)→2AgCl(s)+Ca(NO3)2(aq)
What mass of silver chloride can be produced from 1.51 L of a
0.201 M solution of silver nitrate?
Express your answer with the appropriate units.
The reaction described in Part A required 3.51 L of calcium chloride. What is the concentration of this calcium chloride solution?
Express your answer with the appropriate units.
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For the molecular compound carbon tetrabromide, what would you multiply "molecules of CBr4" by to get the units "grams of CBr4"?
For the molecular compound carbon dioxide, what would you multiply "molecules of CO2" by to get the units "grams of CO2"?
How many ATOMS of carbon are present in 1.85 moles of carbon monoxide ? How many MOLES of oxygen are present in 3.38×1022 molecules of carbon monoxide ?
How many GRAMS of sulfur are present in 2.60 grams of sulfur dichloride
How many GRAMS of sulfur dichloride can be produced from 4.61 grams of chlorine ?
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Calculate the weight % of acetic acid in the vinegar. Calculate your percent error. For this calculation, assume that the density of vinegar is 1.01g/mL.
0.8488 Molarity of acetic acid in my experiment.
I'm a little confused-if you solve it can you be sure to specify what the conversion factors are in the calculations. Thank you!
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A certain material's temperature increases by 1.0 C for every 1560J that it gains. A 0.1964g sample of quinone (molar mass= 108.1 g/mol) was burnt, and the surrounding material's temperature increased from 20.3C to 23.5C. Find the molar heat of reaction for the combustion of quinone.
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Dozens of pharmaceuticals ranging from Cyclizine for motion sickness to Viagra for impotence are derived from the organic compound piperazine. Solutions of piperazine are basic (Kb1 = 5.38 x 10^-5, Kb2 = 2.15 x 10^-9). What is the pH of a 0.0130 M solution of piperazine? Please explain!
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For each solution, state the equation for the hydrolysis reaction that occurs and state the equation for the dissolution of the solid salt in water:
1) HCl
2) Fe(NO3)3
3) HC2H3O2
4) NaH2PO4
5) NH4Cl
6) NaCl
7) NH4C2H3O2
8) NaC2H3O2
9) NaHCO3
10) Na2HPO4
11) NH3
12) NaOH
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Sulfur (2.56 g) was burned in a constant volume calorimeter with excess O2(g). The temperature increased from 21.25 °C to 26.72 °C. The bomb has a heat capacity of 923 J/K, and the calorimeter contained 815 g of water. Calculate ΔU per mole of SO2 formed for the reaction
S8(s) + 8 O2(g) → 8 SO2(g)
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