May 17, 2013

## How do you lose weight by counting calories?

Ive heard that you have to subtract something from some calorie intake i dont know but could somebody help me?
Something about your calorie intake and you minus something and thats how much calories your suppose to have in order to lose weight……

First, don’t believe the myth that “a calorie is a calorie.” If twins are both on 1900 calorie diets and one twin eats chicken, whole wheat, and vegetables and the other eats pure sugar, which is going to be healthier at the end?

If you eat “clean” foods like the ones mentioned above, then you can count a calorie as a calorie within moderation. The big deal when calorie counting is to make sure your diet is still balanced. Balance your carbs, proteins and fats according to the food pyramid and you should be able to count your calories down to weight loss success.

EDIT: The formula your speaking of is {Your ideal weight}x100 = Your total daily calories, but that formula is unsafe. The body needs no less than 1200 calories a day for basic function and even more than that if you do any physical activity.

## How do you calculate airplane fuel consumption?

Just wanted to make sure… I have to calculate the fuel consumption of a plane in litres per passenger per 100 km… to do that would i just divide my litres by the number of passengers and then divide that number by my kilometers and then multiply it by 100? thanks!

Note:This is NOT how fuel consumption is calculated in the real world.
For the purposes of your question,
it could be solved by the following:

liters per km x100 divided by number of passengers.

## What mass of this alloy, in grams, must you weigh out to obtain a sample containing 6.70×10 to the 23 atoms?

The alloy is only 8% cadmium and it is looking for the amount to get that many cadmium atoms. I have been racking my brains over this problem for half an hour but just can’t get it to work!
The alloy is 8.0% cadmium. That is the EXACT wording of the question.

Basically from what i can understand of your poorly worded problem use avogadroes number 1mole=6.02×10^23 atoms. You can work out that there are (6.7×10^23)/(6.02×10^23)=1.1moles of the alloy. MolesxMM=mass

in relation to the cadmium thing i can’t really understand what your asking. If you copy the problem out i could probably answer it.

Ok so 8% of the sample presumably (W/W) is cadmium

8%=6.7×10^23 atoms

1.11=mass/112.4=125.1grams of cadmium are in the sample

8%=125.1
1%=125.1/8
1%=15.6g
x100=1563.7grams of alloy

so essentially 0.08% w/w of 1563.7grams is cadmium.

Think thats right. Haven’t slept in about 27hours though

## How do I find percent yield of an equation?

What are the steps for percent yield in a chemical equation?

1) write a balanced equation
2) convert everything given to moles
3) determine limiting reagent by comparing moles of each reactant to coefficients of balanced equation
4) convert moles limiting reagent to moles of other species via the coefficients of the balanced equation
5) convert moles back to mass. This is “theoretical mass” aka “theoretical yield”
6) % yield = actual recovered mass / theoretical mass x100%

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do you have a specific problem?