A penny for the scratch test (low hardness)a hand lens for inspection a peice of tile for a streak test a geologic hammer to test for cleavage of fracture and the pocket knife for the scratch test (high hardness)
Answer: E. trigonal planar
Explanation:
The trigonal planar geometry is made up of 3 equally spaced sp2 hybrid orbitals arranged at angle 120° to each other, The molecule are electron deficient and does not follow octet rule. Therefore, a molecule containing an sp2 hybrid central atom has a trigonal planar geometry e.g boron hydride (BH3)
Answer: 78.69 g of Fe
Explanation: Iron(III) oxide is Fe2O3. It has a molar mass of 159.7 g/mole. That consists of:
2 x Fe at 55.85 = 11.69 or 69.94%
3 x O at 16.0 = 48.0 or 30.06%
Therefore 112.5 grams will contain (112.5 g)*(69.94%) = 78.69 g of Fe
Answer: option B. The number of the outer most energy level for elements in that period
Explanation:
Cro42ag
What is the percent for the fraction nine twentieths?
1.
9%
2.
20%
3.
45%
4.
90%