You are measuring lead by atomic absorption spectroscopy, a technique that is known to respond linearly to lead concentration. One 10.0 mL portion of river water is added to a 25.00 mL volumetric flask and diluted to the mark. A second 10.0 mL portion is added to another 25.00 mL volumetric flask. 5.00 mLs of a standard solution containing 4.0 ppm Pb are added to the second flask which is then diluted to the mark. The measured absorbance for the first flask is 0.178. The measured absorbance for the second flask is 0.287. Use this information to calculate the concentration of lead in the river water.

Follow the steps provided in the simulation to add water to the graduated cylinder, select one of the three samples (copper, silver, or gold), set its mass to the values given in the statements below, and calculate its density. here is a summary of the steps required: add water by clicking and holding prepare a known volume of water button. until the desired volume of water has been added. if more than the desired volume is added, click the reset button. button and redo the procedure. a single click will add about 21.0 ml of water. to set the mass, click and hold weigh out metal button. until the desired amount of metal is added to the weighing pan. once the desired mass of the metal is added, release the button. transfer the metal to water and then click on calculate density button. to see how the density is calculated using water displacement to measure the volume of the solid. to save time you can approximate the initial volume of water to â±1 ml and the initial mass of the solid to â±1 g. for example, if you are asked to add 23 ml of water, add between 22 ml and 24 ml. which metals in each of the following sets will have equal density? check all that apply.

The reactions shown here can be combined to make the overall reaction c(s) + h2o(g) ⇌ co(g) + h2(g) by reversing some and/or dividing all the coefficients by a number. a. c(s) + o2(g) → co2(g) k=1.363×10^69 b. 2 h2(g) + o2(g) → 2 h2o(g) k=1.389×10^80 c. 2co(g) + o2 (g) → 2 co2(g) k=1.477×10^90

What is the temperature of 0.750 mol of a gas stored in a 6,850 ml cylinder at 2.21 atm? . 2.95 k 5.24 k 138 k 246 k