For the following calculations SHOW ALL WORK!! (6 points each) 7. The half- life of molybdenum-99 is 67.0 hours. How much of a 1.000 gram sample
remains after 335 hours.

8. Determine the average atomic mass of gallium if 60.00% of its atoms have a mass of
68.926 amu and 40.00% have a mass of 70.925 amu.

Balance and in which category does it fit in? single or double displacement or synthesis or decomposition? (a) k2 o → k + o2 (b) na + i2 → nai (c) cu(no3 )2 + naoh → cu(oh)2 + nano3 (d) kclo3 → kcl + o2 (e) ca(no3 )2 + hbr → cabr2 + hno3 (f) sn(oh)2 → sno + h2 o (g) p4 + n2 o → p4 o6 + n2 (h) fe + al2 (so4 )3 → feso4 + al (i) alcl3 + na2 co3 → al2 (co3 )3 + nacl (j) c3 h6 + o2 → co2 + h2 o