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General Chemistry

Percentage yields

A chemist isolates 17.43 g of product from a reaction that has a calculated theoretical yield of 21.34 g. What is the percentage yield?

Wavelength and Frequency Example Problem

Question 1: M. tuberculosis, the organism that causes tuberculosis, can be completely destroyed by irradiation with UV light with a wavelength of 254 nm. What is the frequency? Question 2: Aradio station's signal broadcasts at a freq. 1240kHZ. What is the wavelength in meters?

Chemical Symbol Elements

Give the name and chemical symbol for: a) An element with 50 electrons b) An element with 28 protons c) An element with 2 electrons in the first shell, 8 electrons in the second shell, 8 electrons in the third shell, and 2 electrons in the fourth shell d) An element with atomic number of 78

Distinguish Ionic or Covalent Bonding

While you are working in the lab your instructor hands you a vial of red, crystalline material and asks you to tell if it has ionic or covalent bonding. Describe at least one experiment you would do to answer the instructor's question.

Compound or a mixture?

Tell whether the following is a property of a compound or a mixture: a) Can contain three elements in a specific ratio b) Varies in chemical composition depending on the sample size c) Can be classified as either homogeneous or heterogeneous

Heterogeneous and homogeneous mixture

Tell if the mixture is homogeneous or heterogeneous and explain why you classified it as homogeneous or heterogeneous. a) Iced tea b) Salad c) Chocolate chip cookie

Volatility

Suppose you were given samples of two different liquids. Describe how you would determine which one is more voliatile.

Working with molecules in first excited rotational state

Calculate the ratio of HCL molecules in the first excited rotational state to those in the ground state @ 25 C. Assume an equilibrium bond distance of 1.275 angstroms. the angstrom part of the problem throws me off, I usually start these out by solving Change in E = ( h ) ( c )(Wo), but this is a q (rot) prob, not a q (elec).

Isotopes of Hydrogen Elements

Name the three isotopes of the element whose atomic number is 1. (b) What collective name do we give to a mixture of these three isotopes when they are present in the same ratios as in the universe as a whole?

Conversions

The volume of a certain bacterial cell is 1.60 µm3. (a) What is its volume in cubic millimeters (mm3)? (b) What is the volume of 105 cells in liters (L)? [show all the conversion factors that were used in calculating the answers]

Particle in a Box Proportionality

A particle is constrained to lie along a one-dimensional line segment between 0 and a. The probability of finding the particle along this line segment is seen in attached file. A. Find the proportionality constant, ie., normalize the function. B. Calculate the expectation values of X and X^2 for n=1 and n=2. C. Find t

Dilution Processes

I need help in solving this word problem: A corrupt barman attempts to prepare 100ml of some drink by mixing 30ml of ethanol with 70 ml of water. Does he succeed? If not, what volumes should have been mixed in order to arrive at a mixture of the same strength but of the required volume?

Precipitation calculations

Precipitation Calculations. Will a precipitate of calcium sulfate (Ksp = 2.4 x 10-5) form when 50.0 mL of 0.00150 M calcium chloride and 25.0 mL of 0.0100 M sodium sulfate are mixed? Why or why not?

Colors and Bands

What color has the smallest band in the spectrum of a tungsten light bulb? I have guessed yellow because the waves are shortest but don't know if I am right.

Total Pressure

A closed flask contains a .25 moles of O2 which exerts a pressure of .50 atm. If .75 moles of CO2 is added to the container what is the total pressure in the flask? Please provide step by step instructions with explanation.

General Chemistry - Orbitals and Configuration

Which one of the following configurations depicts an excited oxygen atom? a. 1s22s22p2 b. 1s22s22p23s2 c. 1s22s22p4 d. [He]2s22p4 e. 1s22s22p1 In a ground-state manganese atoms, the _____ subshell is partially filled. a. 4s b