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An unknown substance has a mass of 43.9 g. The temperature of the substance increases from 27.1oC to 42.7oC when 89.1 J of heat is added to the substance. Substance Specific Heat (J/g·°C) Lead 0.130 Silver 0.240 Copper 0.385 Iron 0.442 Aluminum 0.892 Water 4.184   a) What is the specific heat of the unknown substance ? [a] J/goC b) Based on the substances shown on the table above, what is the most likely identity of the unknown substance ?[b]

If a gaseous mixture is made by combining 3.13 g of Ar (0.0783 moles) and 2.69 g (0.0321 moles) of Kr in an evacuated 2.50 L container at 25.0oC. What is the partial pressure of Ar in atm ? PAr = [Ar] atm What is the partial pressure of Kr in atm ? PKr = [Kr] atm What is the total pressure exerted by the gaseous mixture in atm ? Ptotal = [total] atm

An unknown substance has a mass of 14.8 g. The temperature of the substance increases from 27.1oC to 42.7oC when 89.1 J of heat is added to the substance. Substance Specific Heat (J/g·°C) Lead 0.130 Silver 0.240 Copper 0.385 Iron 0.442 Aluminum 0.892 Water 4.184   a) What is the specific heat of the unknown substance ? [a] J/goC b) Based on the substances shown on the table above, what is the most likely identity of the unknown substance ?[b]

Use the following enthalpies of formations (∆Hof): CH4(g) HCN(g) NH3(g) ∆Hof -74.6 kJ/mol 135.5 kJ/mol -45.9 kJ/mol to calculate the standard enthalpy of reaction (∆Horxn) for the following reaction: CH4(g) + N2(g) → HCN(g) + NH3(g) ∆Horxn = ?

Draw the Lewis structure of SF6 on your exam work paper, which you will submit under Exam 5 work Apply VSEPR theory and answer each of the following questions on the exam  a) Total number of valence electrons. [a] valence electrons b) Number of lone pairs on central atom. [b] lone pairs c) Molecular Geometry. [c] shape d) Polar or Nonpolar. [d] molecule

An unknown substance has a mass of 1.37 g. The temperature of the substance increases from 27.1oC to 42.7oC when 89.1 J of heat is added to the substance. Substance Specific Heat (J/g·°C) Lead 0.130 Silver 0.240 Copper 0.385 Iron 0.442 Aluminum 0.892 Water 4.184   a) What is the specific heat of the unknown substance ? [a] J/goC b) Based on the substances shown on the table above, what is the most likely identity of the unknown substance ?[b]

In the fermentation process, yeast converts glucose to ethanol and carbon dioxide. What volume of carbon dioxide, measured at 745 torr and 25.0°C, can be produced by the fermentation of 24.0 g of glucose? C6H12O6(aq)  → 2C2H5OH(aq)   + 2CO2(g)

Calculate the molar mass of a gas if 0.611 g of this gas occupies 0.250 L at 0.955 atm and 297 K. Show all your work for full credit. Use the correct number of significant figures.

An unknown substance has a mass of 23.8 g. The temperature of the substance increases from 27.1oC to 42.7oC when 89.1 J of heat is added to the substance. Substance Specific Heat (J/g·°C) Lead 0.130 Silver 0.240 Copper 0.385 Iron 0.442 Aluminum 0.892 Water 4.184   a) What is the specific heat of the unknown substance ? [a] J/goC b) Based on the substances shown on the table above, what is the most likely identity of the unknown substance ?[b]

Consider the reaction: 4HCl(aq) + MnO2(s) → MnCl2(aq) + 2H2O(l) + Cl2(g) A sample of 29.3 g MnO2 (molar mass = 86.94 g/mol) is added to a solution containing 37.0 g HCl (molar mass = 36.46 g/mol). a) How many moles of Cl2 can be obtained from MnO2? b) How many moles of Cl2 can be obtained from HCl? c) How many moles of Cl2 can be obtained in this reaction? d) How many grams of Cl2 (molar mass = 70.91 g/mol) can be obtained in this reaction? e) What is the limiting reactant? f) If the yield of the reaction is 79.9 %, what is the actual yield of Cl2? Show all your work for full credit. Use the correct number of significant figures.