Iron reacts with oxygen to produce iron(III) oxide.
4 Fe(s) + 3 O2(g) ? 2 Fe2O3(s)
If 7.18 moles of Fe react with excess O2, how many moles of Fe2O3 can be formed?
- 14.4 mol
- 7.18 mol
- 5.39 mol
- 3.59 mol
- 4.79 mol
2- Two electronic balances are tested using a standard weight. The true mass of the standard is 5.0000 g. The results of 5 individual measurements on each balance are recorded below.
Balance ABalance B 5.2895 g5.0001 g 5.1077 g4.9998 g 4.6407 g4.9999 g 4.8947 g5.0002 g 5.0672 g4.9999 g average mass =5.0000 g5.0000 g
Which statement best describes the results?
- A: good precision, good accuracy. B: poor precision, good accuracy.
- A: good precision, poor accuracy. B: poor precision, good accuracy.
- A: good precision, good accuracy. B: good precision, poor accuracy.
- A: poor precision, good accuracy. B: good precision, poor accuracy.
- A: poor precision, good accuracy. B: good precision, good accuracy.
3- What is the correct formula for an ionic compound that contains magnesium ions and phosphide ions?
4- Which of the following statements is/are CORRECT according to valence bond theory?
1.The overlap between an s orbital and a p orbital is called a pi-bond. 2.The overlap of two s orbitals in H2 is called a sigma bond. 3.HF is formed from the overlap of a hydrogen 1s orbital with a fluorine 2p orbital.
- 1 only
- 3 only
- 2 and 3
- 1, 2, and 3
- 2 only