4 x 0.05 = 0.2
2
4x 5
There are six factor pairs: 392 = 1 x 392 392 = 2 x 196 392 = 4 x 98 392 = 7 x 56 392 = 8 x 49 392 = 14 x 28
2 x 2 x 2 x 7 x 7 = 392
7 x 56 = 392
it is a method of estimation used in school e.g 698,656,675,689=700,700,700,700next step is to multiply 700 X 4=2800
If you rounded to the nearest hundred, you could do 7300 x 600, so your estimated guess would be 4,380,000. The actual answer is 4,612,336.
There are six factor pairs: 392 = 1 x 392 392 = 2 x 196 392 = 4 x 98 392 = 7 x 56 392 = 8 x 49 392 = 14 x 28
392 56 x 7 = 392
392 = 2 x 2 x 2 x 7 x 7.
2 x 2 x 2 x 7 x 7 = 392
2 x 2 x 2 x 7 x 7 = 392
7 x 56 = 392
98 x 4 = 392
The prime factorization of 392 is 2 x 2 x 2 x 7 x 7 or 23 x 72.392= 2x2x2x7x7
78.4 (just take 392 x 0.20)
36.41% = .3641 g of H2O 63.59% = .6359 g of MnCl2 .6359g MnCl2 x (1molm MnCl2/125.84g MnCl2)=.0051 mol MnCl2 .3641g H2O x (1 mol H2O/ 18.02g H2O) = .0202 mol H2O .0051 mol MnCl2 / .0051 = 1mol MnCl2 .0202 mol H2O /.0051 = 3.96 = 4 mol H2O Formula is: MnCl2 4H2O Manganese (II) chloride tetrahydrate
392
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