29. A sample of air was collected near a busy street in LA county. The air sample contained PM2.5 particles that have a total mass of 6.0 x 10 ug (micrograms). The air sample was collected in a container that measures 3.0x10-2 m (length) by 1.0x10-2 m (width) by 1.0x10-² m (height). Calculate the density in units of ug/m2 (micrograms per cubic meter). Look up the World Health Organization guidelines for PM2.5 (or do a google search for “who pm2.5 guidelines") and discuss if the level may be harmful to health. A) 2.0 x 10+! B) 2.0 × 10-11 C) 2.0 × 10-17 D) 5.0 E) 2.0 x 10*7 ug/m³ ug/m ug/m³ ug/m³ ug/m³

A chemist prepares a solution of sodium nitrate NaNO3 by measuring out 101.μmol of sodium nitrate into a 450.mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in μmol/L of the chemist's sodium nitrate solution. Be sure your answer has the correct number of significant digits.

3. When a piece of metal weighing 108 g is submerged in water the volume changes from 36.9 mL to 49.2 mL. Calculate the density of this metal. 4. The accepted value for the density of a certain metal is 6.81 g/cm³ . Calculate the percent error in a laboratory measurement that gives a density value of 6.6 g/cm³ . Express this result in the proper number of significant figures.

Measurement and Matter Adding or subtracting and multiplying or dividing measurements 0/3 B A chemistry student must write down in her lab notebook the concentration of a solution of potassium chloride. The concentration of a solution equals the mass of what's dissolved divided by the total volume of the solution. Here's how the student prepared the solution: The label on the graduated cylinder says: empty weight: 1.500 g She put some solid potassium chloride into the graduated cylinder and weighed it. With the potassium chloride added, the cylinder weighed 40.22 g. She added water to the graduated cylinder and dissolved the potassium chloride completely. Then she read the total volume of the solution from the markings on the graduated cylinder. The total volume of the solution was 172.08 mL. What concentration should the student write down in her lab notebook? Be sure your answer has the correct number of significant digits. A Om g·mL -1 □×1 x10 x 5