It would be 50 grams filled up with water to make 1kg.
Though many recipes have enough tolerance (or are worded wrongly from the start) to put in this case 50grams in 1Liter of water.
And it displaces one cubic centimeter.Got it, I think. I seem to remember from GCSE chemistry that a mililitre of water weighs a gram, which bears out what you are saying here.
The great example of add 50ml of water to 50ml of alcohol you end up with 95ml. I will leave it to PE to explain the whole hydrogen bonding , shielding thing .But, as you add materials to water, it expands or contracts. This is confusing to many.
You can make g/g or what is called weight / weight solutions to make up something or you can use g/v or weight / volume. The former says weight out 5 g of x and add to water to make 100 g of total solution and this is w/w. OTOH, g/v suggests using 5 g of x and adding water to make 100 ml of solution. This is a very subtle difference that becomes greater as percentage goes up or if the reaction generates or absorbs heat.
Then there is the school that uses g/g in this sense, 5 g of x and 100 g of water. This uses a method called "molal" which varies from compound to compound and really is not good.
If you measure viscous liquids such as HC110, you should use v/v, another method. In this you take 5 ml of HC110 and add water up to 100 ml as one example.
And 1 cc of water is 1 gram of water only at 20C.
PE
But, as you add materials to water, it expands or contracts. This is confusing to many.
You can make g/g or what is called weight / weight solutions to make up something or you can use g/v or weight / volume. The former says weight out 5 g of x and add to water to make 100 g of total solution and this is w/w. OTOH, g/v suggests using 5 g of x and adding water to make 100 ml of solution. This is a very subtle difference that becomes greater as percentage goes up or if the reaction generates or absorbs heat.
Then there is the school that uses g/g in this sense, 5 g of x and 100 g of water. This uses a method called "molal" which varies from compound to compound and really is not good.
If you measure viscous liquids such as HC110, you should use v/v, another method. In this you take 5 ml of HC110 and add water up to 100 ml as one example.
And 1 cc of water is 1 gram of water only at 20C.
PE
Follow the instructions packaged with the developer or whatever.Very interesting. Thanks to all who have replied. So this is why development times always assume 20C.
And mixing up the Ilford powdered developers (I've only ever used Ilford, living in the UK), the instructions on the pack are to add water up to 1 litre of volume at 40C. Am I correct in thinking this is the g/v method, and that the higher temperature is to speed up the dissolving? Presumably also the g/g method would not be optimal since the temperature change would affect the weight, although presumably also the difference would be negligible...
Nearly lost all respect for you there PE! I take it wt/wt means weight/weight? Would you really advocate weighing out hc110 rather than using a syringe and rinsing it out for example?I have edited my egregious error in that last post. For viscous liquids use wt/wt due to the fact that a viscous liquid cannot pour easily! You cannot get it all out of the measuring container.
My apologies for this terrible error. It must have been the hour. IDK.
PE
that's how I use it 1mg =1 mlA simple question and I'm sure the answer will be simple. I often see advice to make a solution up at a percentage or ratio of weight of solid to volume of liquid. Does one milligram equate to one millilitre? So say a 5% solution of potassium ferricyanide. Would that be 50 milligrams of chemical in 1 litre of water?
Thanks,
Jez
A syringe which can be evacuated totally, due to its construction, is fine as long as there is no residue left in the tip of any significant amount. Many syringes are made to compensate for the tip residue, but it often does not consider viscous or dense materials.
For viscous liquids use wt/wt due to the fact that a viscous liquid cannot pour easily! You cannot get it all out of the measuring container.
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