Mass-Mass Conversions

Use the following reaction equation to answer questions 1 and 2. Make sure you balance it first!

NaBr + Ca(OH)2 ---- CaBr2 + NaOH
How many grams of NaBr are needed to produce 187 grams of CaBr2?

Question

Mass-Mass Conversions

Use the following reaction equation to answer questions 1 and 2. Make sure you balance it first!

NaBr  +  Ca(OH)2  ---->  CaBr2  +  NaOH
 How many grams of NaBr are needed to produce 187 grams of CaBr2?

anonymous · Answer

Ok so I need the steps, basically someone to walk me through it, any takers?

chmvijay · Answer

can u balance it :) since Br are there on right so u add 2 Brr on the left

anonymous · Answer

uh not really sure how to balance it either

chmvijay · Answer

2NaBr  +  Ca(OH)2  ---->  CaBr2  +  2NaOH

chmvijay · Answer

can u tell molecular weight of NaBr

chmvijay · Answer

now dont say i dont know :)

anonymous · Answer

since you already have the balanced equation, start with the given mass of CaBr2 divide this by the molecular weight of CaBr2... after doing so, you'd get the moles of CaBr2 which you will need to convert to moles of NaBr using the balanced equation.. since there are 2moles NaBr per mole of CaBr2... then multiply it to the molecular weight of NaBr.

anonymous · Answer

i kinda need someone to walk me through this

anonymous · Answer

like actually show me all the steps

anonymous · Answer

can you balance the equation?

anonymous · Answer

2NaBr + Ca(OH)2 ----> CaBr2 + 2NaOH

anonymous · Answer

yes.!     you copied this from above..  havent you??? :)

anonymous · Answer

yup

anonymous · Answer

now, observe that 2 moles of NaBr produce 1 mole of CaBr2

anonymous · Answer

ok

anonymous · Answer

i want you to find the molar mass of NaBr and CaBr2
use a periodic table .... 
can you do this ?

anonymous · Answer

yup one sec

anonymous · Answer

NaBr=102.89
CaBr2=199.89

anonymous · Answer

good!

i.e. 1 mole NaBr has 102.89g weight and 
1 mole CaBr2 has 199.89g weight..

follow this thing?

anonymous · Answer

follow what thing?

anonymous · Answer

i mean to say,, what i said you understood?

anonymous · Answer

yeah i have the molar masses now what?

anonymous · Answer

now, you can say that to get 199.89 grams of CaBr2, you need 2 * 102.89 grams of NaBr.

i multiplied by 2 because 2 moles of NaBr are needed to produce 1 mole CaBr2..

anonymous · Answer

ok and then what?

anonymous · Answer

now, it's just unitary method.

        199.89 grams of CaBr2   produced by    205.78 grams of NaBr
then, 187 grams of CaBr2        produced by       $$\frac{ 205.78 }{ 199.89 }\times 187$$

anonymous · Answer

the ans. will be the no. of grams of NaBr required to produce 187 grams of CaBr2

anonymous · Answer

got it?

anonymous · Answer

I got 192.51 grams

anonymous · Answer

I think so