6.02 x 1023 atoms C. 6.02 x 1023 ions B. 6.02 x 1023 grams D. 6.02 x 1023 molecules 5. What ts the correct unit of a formula weight? A. gram B mol C. gram/mol D. mole/gram 6. How many individual atoms are there in 250 grams of O2?
(c) Calculate the mass of water formed when 20 g of methane undergoes complete combustion. 6 Deduce the empirical formulae of the following: Moles and empirical formulae 1 Calculate the molar mass of these compounds. (Relative atomic masses H = 1; N = 14; O = 16; Mg = 24; S = 32; Ca = 40; K =39; Cr = 52; Fe = 56.) (a) calcium ethanoate, Ca(CH3CO2)2 (b) chromium sulfate Cr2(SO4)3 (c) magnesium hydroxide, Mg(OH)2 (d) potassium cyanoferrate(III), K3Fe(CN)6 2 When 2.4 g of magnesium
Practice Test for 6.1-6.3 1. Complete the following molarity calculations: a. What is the molarity of a solution containing 25.3 grams of copper (II) chloride dissolved in 140 mL of water? b. How many grams of sodium hydroxide are needed to make 2 L of a 0.05 M solution?
Calculate the molarity of an aqueous solution resulting when 275 ml of 3.15 M glucose is diluted with 150 ml of water. M1V1 = M2V2 Total volume = 275 ml + 150 ml = 425 ml 3.15 M x 275 ml = M2 x 425 ml [pic] 3. How many grams of sodium hydroxide are in 36.7 ml of 2.256 M sodium hydroxide? [pic] 4. What is the concentration of glucose in ppm in a 0.00025 M glucose solution?
Practice Question for Exam 2 Chem 103 |A chemical reaction requires 30.77 kJ. How many kilocalories does this correspond to? | |A) 7,354 kcal B) 7.354 kcal C) 128.7 kcal D) 0.1287 kcal E) 30.77 kcal | |776 J is the same quantity of energy as | |A) 7.76 × 105 kJ. B) 1.85 × 102 kcal. C) 0.185 kcal.
The RQ was 0.79, which indicates that the 33% of the kcal that the subject was using came from carbohydrates and that 67% of the kcal came from fat. In the 100W stage the volume of carbon dioxide was 4.08L/min and the volume of oxygen consumed was 4.1L/min. The RQ came out o be 0.99, the substrate being used was only carbohydrates at this point. The 200w stage had a carbon dioxide volume of 7.91L/min and a oxygen consumed volume of 6.51L/min. The RQ was 1.2 which indicates that the body is producing more carbon dioxide than the oxygen being consumed.
1) Calculate the number of moles in each of the following solutions:- a) 2.0 dm3 of 0.050 mol.dm-3 hydrochloric acid b) 50 dm3 of 5 mol.dm-3 sulfuric acid c) 10 cm3 of 0.25 mol.dm-3 potassium hydroxide [3] 2) Calculate the volume in cm3 of each solution that contains the following numbers of moles:- a) 0.00500 moles of NaOH with concentration 0.100 mol.dm-3 b) 1.00×10-5 moles of HCl with concentration 0.0100 mol.dm-3 c) 9.25×10-3 moles of KCl with concentration 0.250 mol.dm-3 [3] 3) Find the concentrations of the following solutions in both mol.dm-3 and g.dm-3:- a) 0.400 moles of HCl in 2.00 dm3 of solution b) 12.5 moles of H2SO4 in 5.00 dm3 of solution c) 1.05g of NaOH in 500 cm3 of solution [6] 4) In a titration, 25.0 cm3 of a solution of sodium hydroxide required 18.80 cm3 of hydrochloric acid of concentration 0.0500 mol.dm-3 for neutralisation. Find the concentration of the sodium hydroxide in both mol.dm-3 and g.dm-3. [3] NaOH + HCl ( NaCl + H2O 5) Calculate the volume of 0.05 mol.dm-3 potassium hydroxide solution that is required to react exactly with 25.0 cm3 of 0.0150 mol.dm-3 nitric acid. [2] HNO3 + KOH ( KNO3 + H2O 6) In a titration, 20.0 cm3 of barium hydroxide solution required 28.60 cm3 of sulfuric acid of concentration 0.0250 mol.dm-3 for neutralisation. Find the concentration of the barium hydroxide in both mol.dm-3 and g.dm-3.
Which of the following mass units is the largest? a.|1 cg|c.|1 mg| b.|1 dg|d.|1 ng| 9. If the temperature changes by 100 K, by how much does it change in C? a.|0C|c.|100C| b.|37C|d.|273C| 10. What is the quantity 987 milligrams expressed in grams?
Mg = 24 g/mole Percent of an element = Mass of the element X 100 C = 12 g/mol Total formula mass O = 16 g/mol 3. How many grams are there in 0.5 moles of each of the compounds? a) H2S b) Mg c) C12H22O11 d) F2 4. How many particles
RESULTS The first flask held .305 grams; the second, .454 grams; and the third, .477 grams of unknown gas. According to the ideal gas law, at a pressure of 762.0 mmHg and 16.0ºC, a vessel of 250 ml will contain .0105 moles of gas, while a vessel of 252 ml will contain .0106 moles of gas. Dividing the number of grams of unknown gas contained in each flask by the corresponding number of moles contained in that vessel resulted in a molar mass for each of the flasks. The