In which of the following pairs of elements are both members of nonmetals? (A) C

Question

In which of the following pairs of elements are both members of nonmetals? (A) Cu and Br (B) Al and Si (C) P and N (D) Zn and Mg Which element would have physical and chemical properties similar to sulfur? (A) Ar (B) O (C) Br (D) N Which of the following compounds represent a covalent compound? (A)NH_4Cl (B) HCl (C) MgCl_2 (D) FeCl_3 The answer to the subtraction of 23.48-2.012 reported to the proper number of significant figures is (A) 20.09 (B) 21.468 (C) 25.49 (D) 21.47 The measurement 580 g in scientific notation becomes (A) 5.80 times 10^-2 g (B) 5.80 times 10^2 g (C) 5.8 times 10^2 g (D) 5.8 times 10^-2 g How many grams of aluminum (Al) are in 3.01 mole of aluminum? (A) 81.2 g (B) 3.01 g (C) 26.98 g (D) 96.5 g In which of the following lists are the elements arranged in decreasing atomic size (largest to smallest)? (A). Cl, Si, Al (B). Al, Ga, In (C). Ca, Mg, Be (D). O, S, Se How many molecules are in 0.0200 mole of nicotine, a compound present in tobacco? (A.N. 6.022 times 10^23) (A) 1.20 times 10^23 molecules (B) 2.41 times 10^22 molecules (C) 6.02 times 10^23 molecules (D) 1.20 times 10^22 molecules The formula for barium phosphate is (A) Ba_3(PO_4)_2 (B) BaPO_4 (C) Ba_2(PO_4)_3 (D) Ba(PO_4)_3

Explanation / Answer

1) Phosphorous (P) and Nitrogen(N)

2) Oxygen is from same family (O)

3) HCl

4) 23.48-2.012 = 21.47

5) 5.8 X 10^2

6) the atomic weight of Aluminium = 27

The weight of 1 mole = 27 grams

so weight of 3.01 moles = 27 X 3.01 = 81.27 g

7) Decreasing : Ca > Mg > Be

8) The number of atoms in 1mole = 6.023 X 10^23 molecules

Number of molecules in 0.02 = 6.023 X 10^23 X 0.02 = 1.2046 X 10^22

9) Ba2(PO4)2

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