Chemistry, 26.08.2019 20:20 smmailloux7249

2,083,193 cm in scientific notation rounded into 2 sig figs

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Answers

Answer from: xavier1283

$\boxed{2.1 \times 10^{6}\text{ cm}}}$

Explanation:

1. Rounding

2 083 193 cm

You want to round to two significant figures.

You replace all the underlined digits (all those after the first two digits) with zeroes.

The rule is: If the first figure dropped (8) is greater than 5, increase the last figure kept (0) by 1.

Then, 2 083 193 cm becomes 2 100 000 cm

2. Converting to scientific notation

A number in scientific notation has the form

N × 10ⁿ

where N is a decimal number called the mantissa and n is an integer called the exponent.

We must have 1 ≤ N < 10

(a) Determine the mantissa

Move the decimal place to the left to create a new number between 1 and 10.

2 100 000 ⟶ 2.100 000; N = 2.1

(b). Determine the exponent.

The exponent is the number of times you moved the decimal to get the mantissa.

You moved the decimal six places to the left, so the exponent n = 6.

(c). Write the number in scientific notation

$\text{The measurement in scientific notation is }\boxed{\mathbf{2.1 \times 10^{6} \textbf{ cm}}}.$

Answer from: Quest

може ли да зареждате повече информация, моля

Answer from: Quest

remember that hf is only the energy of one photon. not two. not three. one. 1) 5.12 * 10^3 photons find the energy of one photon, then determine how many photons are needed to reach the sensitivity. e = hf = (6.626 * 10^-34 js)(5.95 * 10^19 hz) = 3.94247 * 10^-14 j per photon (2.02 * 10^-10 j) / (3.94247 * 10^-14 j/photon) = 5123.69149 photons round to three sig figs. 2) 5.77 * 10^-17 j energy of pulse = energy per photon * number of photons = hfn = (6.626 * 10^-34 js)(1.66 * 10^13 hz)(5250) = 5.774559 * 10^-17 j round to three sig figs. 3) 4.07 * 10^8 kj/mol 10^12 pm = 1 m c = fλ f = c/λ e = hf = hc/λ = [(6.626 * 10^-34 js)(3.00 * 10^8 m/s) / (2.94 * 10^-12 m)](1 kj/1000 j)(6.02 * 10^23 photons/mol) = 40702571.4 kj/mol round to three sig figs. 4) 9.94 * 10^-1 m e = hc/λ λ = hc / e = (6.626 * 10^-34 js)(3.00 * 10^8 m/s) / (2.00 * 10^-25 j) = 0.9939 m round to three sig figs. 5) 9.06 * 10^3 photons energy of pulse = energy per photon * number of photons number of photons = energy of pulse / energy per photon = energy of pulse / (hf) = (3.87 * 10^-13 j) / [(6.626 * 10^-34 js)(6.45 * 10^16 hz)] = 9055.23695 photons round to three sig figs. 6) 2.78 * 10^-15 j this is problem 1, except in reverse. sensitivity = minumum number of photons * energy per photon = (5930)(6.626 * 10^-34 js)(7.077 * 10^14 hz) = 2.78070758 × 10^-15 j round to three sig figs.