How many moles of Ca are in 1.25x1023 atoms? We used two conversion factors in this unit, they are provided below. It is your responsibility to know which conversion factor to use!

Avogadro’s number: 6.02x1023 atoms = 1 mole

Molar mass of calcium: 40.078 g Ca = 1 mol Ca

A. 3.12x10^21 mol

B. 0.21 mol

C. 3.12 mol

D. 0.21x10^21 mol

B. 0.21 mol

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Step 1: Define

1.25 × 10²³ atoms Ca

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

0.207572 mol Ca ≈ 0.208 mol Ca

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.