A sample of cross-linked natural rubber (polyisoprene) is found to have shear modulas G = 217...

A sample of cross-linked natural rubber (polyisoprene) is found to have shear modulas G = 217 kPA at 20 C. Deduce N, the number of sub-chains between crosslinks per m^3 and hence the number average degree of polymerization between crosslinks. The chemical structure of polyisoprene. You may take for relative atomic mass C=12 and H=1, and for the density rho=909 kg/m^3. Assume <r^2>i = <r^2>o.

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Amanda K answered 2 years ago

9a) A sample of an unknown gas is found to have a density of 1.07 g/L...

9a) A sample of an unknown gas is found to have a density of 1.07 g/L at a pressure of 0.783 atm and a temperature of 56 °C. Assume ideal behavior. The molar mass of the unknown gas is ____g/mol. b) A sample of oxygen gas has a density of _____g/L at a pressure of 1.20 atm and a temperature of 38 °C. Assume ideal behavior. c) A mixture of xenon and oxygen gases, in a 6.72 L flask at...

At 25 oC a 0.50 g sample of polyisobutylene (a polymer used in synthetic rubber) in...

At 25 oC a 0.50 g sample of polyisobutylene (a polymer used in synthetic rubber) in 100.0 mL of benzene solution has an osmotic pressure that supports a 5.1 mm column of solution (p = 0.88 g/mL). What is the molar mass of the polyisobutylene? (For Hg, p = 13.6 g/mL)

The dry weight of a natural stone sample is 336 g, the water-saturated weight is 340...

The dry weight of a natural stone sample is 336 g, the water-saturated weight is 340 g, and the water-saturated sample is 196 g in water. The volume of the 50 gr powder sample obtained by grinding the same stone is 18.7 cm3 measured at the picnometer. Calculate the unit weight, specific weight, and weight and volume water absorption rates of this stone.

A stone with a mass of 525 g in air is found to have an apparent...

A stone with a mass of 525 g in air is found to have an apparent mass of 377 g when submerged in water. a. What mass of liquid is displaced? b. What is the volume of the stone? c. What is the average density of the stone?

1) A rock with a mass of 550 g in air is found to have an...

1) A rock with a mass of 550 g in air is found to have an apparent mass of 327 g when submerged in water. a) What mass, in grams, of water is displaced? b) What is the volume, in cubic centimeters, of the rock? c) What is the average density of the rock, in grams per cubic centimeter? 2) Suppose 1.95 L of gas at 37°C is under 7.37 × 107 Pa of pressure. How many moles of gas...

A 1.912-g sample of calcium chloride is decomposed into its constituent elements and found to contain...

A 1.912-g sample of calcium chloride is decomposed into its constituent elements and found to contain 0.690 g Ca and 1.222 g Cl. Calculate the mass percent composition of Ca and Cl in calcium chloride.

coins have a mean of 2.5 g 32 coin sample the sample coins have a mean...

coins have a mean of 2.5 g 32 coin sample the sample coins have a mean weight of 2.49496 standard deviation of 0.01722g with a 0.05 significance level to test the claim this sample from s population with a mean weight of 2.5 gm give test statistic and p value

Dolomite, [CaMg(CO3)2] is found in a soil sample. A geochemist titrates 24.65 g of soil with...

Dolomite, [CaMg(CO3)2] is found in a soil sample. A geochemist titrates 24.65 g of soil with 57.85 mL of 0.3315M HCl. What is the mass % of dolomite in the soil? ( Write answer to two decimal places, ex. 15.77) Following is the acid/base reaction which occurs during the titration: CO3-2(aq) + HCl(aq) --> HCO3-(aq) + Cl-(aq)

Consider a sample of push pins. Their weights are measured and found to have a standard...

Consider a sample of push pins. Their weights are measured and found to have a standard deviation of 2.02 Give a point estimate for the population standard deviation in weights of push pins. Round your answer to two decimal places, if necessary.

A sample of 64 resistors are taken from a production line and are found to have...

A sample of 64 resistors are taken from a production line and are found to have a sample mean of 998 Ohms. The population distribution for the resistances is unknown but the population standard deviation is known to be 10 Ohms. (a) Find a 97% confidence interval for the population mean. The tabulated value is and obtained from table. Lower limit is and the upper limit is . (b) Answer the following two questions by writing either ”narrower” or ”wider” in the blank...

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