A) How many H atoms are present in a 4.25 ng sample of urea, CO(NH2)2? give answer accurate to three signifiacnt figures
B) If 10.24 g of a pure element contains 6.761 x 10 22 atoms, what is the element?
C) What mass of O is found in 58.7 g K2Cr2O7?give answer accurate to 3 significant figures
D) Complete combustion of 1.744 g of a particular hydrocarbon yielded 5.105 g CO 2 and 3.135 g of H 2 O. What is the empirical formula of this hydrocarbon?
E) A 4.2039-g sample of a hydrate of Cu(NO3)2 was heated to drive off all of the water of hydration. The remaining solid weighed 3.2635 g. If Cu(NO3)2.x H2O represents the formula of the hydrate, then what is the value of x?
F) How many grams of H3PO4 are produced if the following reaction yielded 24.1 g HCl? (Enter your answer in grams accurate to 3 significant figures
G) What is the minimum mass of oxygen, in grams, needed to burn 39.7 g C6H6O? Give your answer to three significant figures
H) What is the maximum mass of I2 that can be obtained from 38.2 g KMnO4, 114 g KI and excess H2SO4? Give your answer in grams to three significant figures