Question

leveled practice in 1 and 2, complete the expressions to 1. simplify the expression (9.6×10^(-9))+(2×10^(-10)). express your answer in scientific notation. 2. find (6.5×10^(11))/(1.3×10^(8)). write your answer in scientific notation 4. what is the mass of 75,000 oxygen molecules? express your answer in scientific notation. mass of one molecule of oxygen = 5.3×10^(-23) 6. find (3.8×10^(7))×162. write your answer in scientific notation.

Explanation:

1. Simplify the expression $(9.6\times 10^{-6})+(2\times 10^{-10})$

Step1: Make exponents the same

Since $10^{-10}$ is much smaller than $10^{-6}$, we rewrite $2\times 10^{-10}=0.0002\times 10^{-6}$.

Step2: Add the coefficients

$(9.6 + 0.0002)\times10^{-6}=9.6002\times 10^{-6}$

Step1: Divide the coefficients

$\frac{6.5}{1.3}=5$

Step2: Subtract the exponents

$10^{11 - 8}=10^{3}$

Step3: Combine the results

$5\times10^{3}$

Step1: Write 75000 in scientific - notation

$75000 = 7.5\times 10^{4}$

Step2: Multiply the number of molecules by the mass of one molecule

$(7.5\times 10^{4})\times(5.3\times 10^{-23})$

Step3: Multiply the coefficients and add the exponents

$(7.5\times5.3)\times10^{4+( - 23)}=39.75\times 10^{-19}$

Step4: Adjust to scientific - notation

$3.975\times 10^{-18}$

Answer:

$9.6002\times 10^{-6}$

2. Find $\frac{6.5\times 10^{11}}{1.3\times 10^{8}}$