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Calculate the frequency of the red light emitted by a neon sign with a wavelength of 659.9 nm.

Conversion of units: A person on a diet loses in a week. How many are lost?

A 25.5 mL aliquot of HCl (aq) of unknown concentration was titrated with 0.113 M NaOH (aq). It took 51.2 mL of the base to reach the endpoint of the titration. The concentration (M) of the acid was ________.

When evaluating for acute deep vein thrombosis (DVT) in the lower extremity, reversal of flow of the Doppler signal lasting longer than 0.5 second when the sample volume is placed within the vein indicates __ valvular incompetence

What event occurred in the Byzantine Empire in the late fifteenth century that limited Europe’s access to spices from the East?

If a reaction of 5.0 g of hydrogen with 5.0 g of carbon monoxide produced 4.5 g of methanol, what was the percent yield?   2H2 + CO ® CH3OH

Which of the following was one of the causes of Greek colonization and particularly persistent problem for Sparta?

A 4.00 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a bomb calorimeter with a heat capacity of 4.25 kJ/°C. If the temperature rose from 29.5°C to 60.5°C, determine the value of ΔH°comb for aniline.

If 4.89 g of ZnCl2 is dissolved in enough water to give a total volume of 500 mL, what is the molarity of the solution?

The atomic number of an atom of 13C is