A 2.000-g sample containing Na2CO3 (FM 106.0) is titrated with 0.8500 M HCl. The titration is fully completed with 25.00 mL of HCl. Calculate the percentage of sodium carbonate in the sample (assuming other compositions in the sample does not react with HCl). Na2CO3 2 HCl2NaCl H2O CO2 A. 55.55% Na2CO3 B. 71.62% Na2CO3 C. 43.53% Na2CO3 D. 44.45% Na2CO3 E. 56.31% Na2CO3

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)

How many moles are in 7.2 x 10^23 carbon molecules? (*round to the nearest hundredth and include the unit "mol c" after your number) question 6 options:

If i initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200 k, and then i raise the pressure to 14 atm and increase the temperature to 300 k, what is the new volume of the gas?