How many atoms make up 20.0 grams of chalk (caco3)?

First, find the molar mass of CaCO3 (100.0869 grams, but you can usually look on a periodic table for a less precise number and still be fine).

Convert grams to moles, and moles to atoms

20.0 grams * = 1.20 * .

Check if the answer makes sense.

If you have 20 grams of chalk, you have ~20% of a mole of chalk.  This means you have ~20% of the atoms a normal mole of chalk would have.

1.2 / 6.02 = 0.199, which is very close to 0.2 a.k.a. 20%

1.consider the following balanced equation and answer parts a through. show calculations for each part.  

3 ag(s) + 4 hno3(aq) → 3 agno3(aq) + no(g) + 2 h2o(l)  

a. calculate the number of moles of agno3 produced by the reaction of 3 moles of ag with excess hno3. if the number to the left of the compound represents the number of moles of the compound which are present, then 3 moles of ag react with 4 moles hno3 to produce 3 moles agno3 (aq).

so the answer to a would be 3 moles.

b. calculate the number of moles of agno3 produced by the reaction of 108 grams of ag with excess hno3.  

i'm not sure how to plug in the grams of silver into an equation using moles to find how many moles are produced.

c. calculate the number of grams of agno3 produced by the reaction of 108 grams of ag with excess hno3  

d. calculate the number of moles of no produced as a byproduct of the reaction of 108 grams of ag with excess hno3.  

e. calculate the number of grams of no produced as a byproduct starting with 108 grams of ag and excess hno3.  

explanation:

why is cellular respiration important for homeostasis?

it changes food into energy that the organism can use.

which of the following is most likely to happen if a cell is not able to divide?

the cell will not be replaced when it is damaged.

explanation: