Answer:
Heat required = 13,325 calories or 55.75 KJ.
Explanation:
To convert a water to steam at 100 degree celsius to vapor, we have to give latent heat of vaporization to water
Which equals ,
Q = mL,
Where, m is the mass of water present
L = specific latent heat of vaporization
Here , m= 25 gram
L equals to 533 calories (or 2230 Joules)
So, Q = 25×533 = 13,325 Calories
Or , Q = 55,750 Joules = 55.75 KJ
so, Heat required = 13,325 calories or 55.75 KJ.
1. The hypothesis for this is experiment is that the 50:50 of methanol-water mixture will not turn to solid when the temperature reaches to -40°C.
2. The procedure for this is measuring equal volumes of water and methanol using the graduated cylinder. You can measure 100 mL of water and 100 mL of methanol using the graduated cylinder. Then, mix them in the beaker. Next, measure 200 mL of water, and another 200 mL of methanol. Don't mix them. Also, make a 60:40 mixture by measuring 120 mL of water and 80 mL of methanol, then mix them together. Place them all in the refrigerator at the same time. Record the time when they would freeze to solid.
3. The controls for this experiment are the 200 mL water alone, and the 200 mL methanol alone.
4. The independent variable in here is the time, while the dependent variable is the temperature of the mixtures.
5. If the hypothesis turns out to be true, then all the mixtures prepared should freeze and become solid after a certain period of time, with the exception of the 50:50 mixture. The 50:50 mixture should still remain as a liquid even when left overnight.
Answer: 72 grams of 
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number 
of particles.
To calculate the number of moles, we use the equation:
Putting in the values we get:
According to stoichiometry:
1 mole of 
requires 5 moles of oxygen
0.45 moles of require= 
moles of oxygen
Mass of 
72 grams of are needed to completely burn 19.7 g
Answer:
D. Is the correct Option!
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<u><em>Hope this helps!!! :)</em></u>
