mole

[April]

What is the number of sodium atoms that contain the same mass as 4.0 g of calcium atoms?

1) If 67.5g of aluminium atoms are completely changed into aluminium ions,what is the total number of electrons released?

2) What is the number of sodium atoms that contain the same mass as 4.0g of calcium atoms?

3) If 8g of nitrogen gas contain X molecules, how many molecules are present in 8g of sulphur dioxide gas? Give your answer in term of X.

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[zileselakovic]

1) Ar(Al) = 27
N (Al)= 67.5/27 * 6*1023 = 15*1023

Al 0 = Al +3 + 3 e-

3* 15 * 1023 = 45 * 1023

2) N (Na) = 4/23 * 6 * 1023 = 1.04 * 1023

3) X= 8/28 * 6 * 1023 = 1.7 * 1023
N(SO₂) = 8/64 * 6 * 1023 = 0.75 * 1023

N= 0.44X