How many grams of water are needed to react with 485g of cac2

273 g  

Step-by-step explanation:

a) Balanced equation

We know we will need an equation with masses and molar masses, so let’s gather all the information in one place.  

M_r:    64.10   18.02

          CaC₂ + 2H₂O ⟶ Ca(OH)₂ + 2C₂H₂

m/g:    485

(b) Mass of H₂O

(i) Calculate the moles of CaC₂

n = 485 g CaC₂ × (1 mol CaC₂/64.10 g CaC₂)

  = 7.566 mol CaC₂  

(ii) Calculate the moles of H₂O

The molar ratio is (2 mol H₂O /1 mol CaC₂)

n = 2.00 mol CaC₂ × (7.566 mol H₂O /1 mol CaC₂)

  = 15.13 mol H₂O

(iii) Calculate the mass of H₂O

m = 165.16 mol H₂O × (18.02 g H₂O /1 mol H₂O)

    = 273 g H₂O

The reaction requires 273 g H₂O.

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answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.