[Ednet]

Hi everyone! I'm pretty new to chemistry and mixing, but I've been tasked to mix 3 types of substances with a certain vol/weight.

To put it simply by identification of A and B chemical and powder,

Given mixture volumes and weight (The Recipe) are like:
Chemical A - 98mL
Powder A   - 2grams
Powder B   - 0.05grams

If I realise that I do not have enough of chemical A, say maybe I'm left with 80mL of it and I'll be happy with having just half of the intended mixture. Does it mean I can also half the weights of both Powders?

Thereby giving me:
Chemical A - 49mL
Powder A   - 1grams
Powder B   - 0.025grams

Hope to hear from anyone soon!

Happy New Year To All Reading This Post! Thank You! 

[Borek]

Yes, dividing everything by two will produce identical solution, just half of it.

[billnotgatez]

I would say that halving of each will result in the same reaction.
It works when you are doing baking.
@Ednet
Can you compute what it should be if you used 80 ml of chemical A?
Are you doing this for home purposes or for a class?
By the way if you have not read forum rules, please do so.

[Ednet]

Yes, dividing everything by two will produce identical solution, just half of it.

Cool! Thanks alot Borek!

I would say that halving of each will result in the same reaction.
It works when you are doing baking.
@Ednet
Can you compute what it should be if you used 80 ml of chemical A?
Are you doing this for home purposes or for a class?
By the way if you have not read forum rules, please do so.

What do you mean by computing chemical A? Do you mean the network structure?

Well, I'm doing this for my own chemical project.
I was thinking of mixing my own photopolymer resin using a recipe from an institution article.

Oh yea! I just read the forum rules. 

[billnotgatez]

@Ednet
Given Recipe #1 and Recipe #2 what would you expect the x and y to be in Recipe #3?
 Note: I am just using the numbers from your original post

Recipe #1
Chemical A - 98 mL
Powder A   - 2 grams
Powder B   - 0.05 grams

Recipe #2
Chemical A - 49 mL
Powder A   - 1 grams
Powder B   - 0.025 grams

Recipe #3
Chemical A - 80 mL
Powder A   - x grams
Powder B   - y grams

[Ednet]

@Ednet
Given Recipe #1 and Recipe #2 what would you expect the x and y to be in Recipe #3?
 Note: I am just using the numbers from your original post

Recipe #1
Chemical A - 98 mL
Powder A   - 2 grams
Powder B   - 0.05 grams

Recipe #2
Chemical A - 49 mL
Powder A   - 1 grams
Powder B   - 0.025 grams

Recipe #3
Chemical A - 80 mL
Powder A   - x grams
Powder B   - y grams

Oh yea!

For Recipe #3, proportionately it'd have to be:

Chemical A - 80 mL
Powder A   - 1.6326 grams
Powder B   - 0.0408 grams

Am I right?

[billnotgatez]

That is not what I am getting
Could you show your computations

[Ednet]

That is not what I am getting
Could you show your computations

Hmm. OK.

Since if I can do it proportionately then,

Chemical A : 80 ml
Powder A : (80/98) * 2 grams = 1.632653061 grams
Powder B : (80/98) * 0.05 grams = 0.040816326 grams

[billnotgatez]

@Ednet
You were correct I had misread your values -- 98 is not 90
Thanks for being patient.

Can you look at the link below and think about how you would deal with Significant figures
http://en.wikipedia.org/wiki/Significant_figures
Also could you tell me what level of accuracy the devices you are using to measure the mL and grams.

I am assuming you want a total discussion about your original question.

[Ednet]

@Ednet
You were correct I had misread your values -- 98 is not 90
Thanks for being patient.

Can you look at the link below and think about how you would deal with Significant figures
http://en.wikipedia.org/wiki/Significant_figures
Also could you tell me what level of accuracy the devices you are using to measure the mL and grams.

I am assuming you want a total discussion about your original question.

Hey! No worries! I tot it was real nice of you to point it out if I had something wrong and you wanted to see how i did my computations and at the same time helped me with my learning.

I'll be taking the precision of my measurements to as close to 3 significant figures as I can, because I can foresee a lack of precision instruments for this home project. I'll try my best though.

I'm thinking of getting a volumetric pipette or a macropipetter of 25ml and an analytical balance (up to 4 decimal place) which I can borrow from a friend.

Is there any device which I can accurately or better dispense the low amounts of powder for measurement? Something not too expensive i hope.. ><