.A sample of alfalfa meal weighing 2.0 g is analyzed by Kjeldahl method for the percentage of nitrogen. The liberated NH3 is caught in a solution of H3B03, and 8.23 ml of HCI are required in the subsequent titration. A sample of pure (NH4)2SO4 (132.12) weighing 0.61 g is treated with excess NaOH and the liberated NH3 (17.04) is also caught in H3BO3. The resulting solution requires 20 ml of the acid for titration. Calculate the percentage of protein in the sample using 6.25 as the factor.

A piece of platnium metal ore obtained was determined to have a mass of 1.6124 grams. The density of platnium is 21.45 g/ml what is the full volume (in liters) of the piece of platnium

Calculate the number of atoms in 264. µg of cadmium. Be sure your answer has the correct number of significant figures. Note: Reference the SI prefixes and Fundamental constants table for additional information. Cd atoms 0 x10 X

Q1. The net potential energy between two adjacent ions, EN, is represented by A В E N pn where EN is the net energy in Joule (J), A and B are constants with values of 1.436 J.nm and 7.32 × 106 J.nm, r is the interatomic distance between the two ions in nanometer (nm), and n is a positive number with a value of 8.

Substance Physical Appearance Fe     S     FeS

Which piece of equipment would you use to measure 7.10 mL of CuSO4 (aq)?

Scientists can learn a great deal about a community's drug use (both legal and illegal) by analyzing the contaminants in wastewater. In a recent study in New York State, chemists measured the concentration of cotinine, a derivative of nicotine that i produced in the liver and excreted in the urine of tobacco users. The chemists found the average cotinine concentrations in the wastewater stream was 1.43 µg/L. a Ι Ι H- b HH H H-C C-N: C=0: TH HH Jonutis/Shutterstock Revell, Introductory Chemistry, 2e, © 2021 W. H. Freeman and Company Cotinine is slightly soluble in water. Using the structure of cotinine, identify any polar covalent bonds that are present in this substance. C-O C-C C-H C-N

ча OH A OH D B с CHO

(2) Draw the (right next splitting patterns to with each for a all unique It's in chemical environment). the molecules below

The world population is estimated to be 7.4 x 109. Nauru is the smallest island nation and comprises 1.5 x 10-4% of the world population. If the percentage of left-handed people is approximately 12%, estimate the number of left-handers on the island of Nauru.