If 278 g of water is contained in a 264 g aluminum vessel at 10?C and an additional 92 g of water at 82?C is poured into the container, what is the final equilibrium temperature of the mixture? The specific heat of aluminum is 900 J/kg · ?C and of water 4186 J/kg · ?C .Answer in units of ?C
The first thing that we need to do is to convert the mass to kilogramsFor cold water, mass 0.278 For aluminum, mass 0.264 For hot water, mass 0.092 In this type of problem, the amount of heat energy that is absorbed by cold water and aluminum vessel is equal to the amount of heat energy that is released by the hot waterLet’s use the following equation to determine the amount of heat energy that is absorbed by the water and aluminum vesselQ m SpHt (Tf – Ti) For cold water, Q 0.278 4186 (Tf – 10) 1163.708 Tf – 11,637.708 For aluminum, Q 0.264 900 (Tf – 10) 237.6 Tf – 2376 Total Q 1401.308 Tf – 14,013.708 For hot water, Q 0.092 4186 (82 – Tf) 31,579.184 – 385.112 Tf Set these two amounts of heat energy equal to each other and solve for Tf1401.308 Tf – 14,013.708 31,579.184 – 385.112 Tf Add 385.112 Tf and add 14,013.708 to both sides1786.42 Tf 45,592.892 Tf 45,592.892 ÷ 1786.42 25.52193325?C The final temperature is approximately 25.53?C To check this answer, let’s put this number into the following equationsTotal Q 1401.308 Tf – 14,013.708 Total Q 1401.308 25.53 – 14,013.708 21,761.68254 Q 31,579.184 – 385.112 Tf Q 31,579.184 – 385.112 25.53 21,747.27464 Since I rounded the final temperature, I believe that this proves that it is correct.
You need to make a 4x4 in square to see how many st in an inchIt usually will state 20 st 4in for whatever the yarn isThis is called guageHere is a link about guage explanation.
I am having the same problem as you and I hesitate to write anything here, because I am no authoritySo that's the warningI look at the yarn they suggest and see how thick/thin it is (the number too).and then I choose something similarI also buy more than I need and figure that if I have a skein left over and it's not too expensive then I will just make a hat and donate it for charitySo far it's working well for meI do know that the person who wrote about gauge is correctYou have to make a swatch to see if what you are doing matches the intent of the patternBut I know that's not what you are askingI also shop at yarn shops now, because they are the authorities and they help me with what will work and whyI've been learning.
This is rather complicated to answer because there are many factors that go into making any one particular yarn successful in a projectWeight or size of the yarn is only one of themThe way it was spun is a major one for meThe fibre content is another - acrylics just do not behave the same way wool will, which is different than cotton, which is different again from silkThe first thing in the yarn store is to compare to see if it is the same sizeYou need a sample of one yarn, and then compare it to anotherThe best way is to cross the lengths of two yarns and then fold them back on themselvesYou will get them hooked on each other (like you link your fingers together) and then you can clearly feel any differencesYou can sometimes see it too, but I find I can feel the difference as I run my fingers over that strand back and forthWhen you think you have a yarn that may work, you still need to work up a sample swatchSorry, it is a pain, I know, but you won't know until you actually use it to see how it will behaveSome yarns compress too much, some stretch, some have no bodyI never look at the labels of yarns because I spin my ownBut as a general rule, I use the crochet hook as a guideThe hook is about the same thickness as two strands of yarn held togetherThat is a general guideIf you want a tighter fabric, use a smaller hookIf you want a looser fabric, then use a larger hookThat is about the easiest way I can describe itIf you can't find the yarn you want, then change the size of the hookThe only correct way to find the substitute for a yarn is going by length per weightIn the US, that is yards per poundIn the rest of the world, that is metres per kilogramBut remember: that is for the same fibre contentSilk weighs more than wool, so you can't compare different fibresWorseted spun is different than woolen spun.
