% nguyên tử của đồng vị $^{65}Cu=100\%-69,1\%=30,9\%$
$\overline{A}_{Cu}=\dfrac{63.69,1+65.30,9}{100}=63,618$
Đáp án:
\({M_{tb}} = 63,618g/mol\)
Giải thích các bước giải:
\(\begin{array}{l}{\% ^{65}}Cu = 100 - 69,1 = 30,9\% \\{M_{tb}} = \dfrac{{63 \times 69,1 + 65 \times 30,9}}{{100}} = 63,618g/mol\end{array}\)
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nếu ta nhân số 12345679 với một số a bất kì có một chữ số , rồi nhân kết quả đó với 9 thì ta được số có 9 chữ số mỗi chữ số đều là a chẳng hạn khi a= 3 thì 12345679 nhân 3 = 37037037 37037037 nhân 9 = 333333333 Em hãy giải thích tại sao
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