Answer: A. the transfer of heat by currents
Explanation: There are three modes of heat transfer:
1) Conduction: This type of heat transfer happens when there is direct contact between the two object. Example: heating a pan on stove.
2) Convection: This type of heat transfer happens when there is a movement of fluid (liquid or gas) due to the movement of hot layers to the top and cold layers to the bottom which leads to convection currents. Example: Heating of swimming pool.
3) Radiation: This type of heat transfer happens when there is direct transfer of energy through space. Example: Heating of earth's surface.
B. The transmission of heat across matter is conduction.
C. The electromagnetic radiation from the surface of an object which is due to the object's temperature is radiation.
D. The transmission of heat across empty space is radiation.
Answer:
Number of neutrons and stability
Explanation:
An isotope of an element is basically the same element but with different number of neutrons. For example here, boron can exist in the forms of boron-10 and boron-11, and so the latter would have one more neutron than the former one.
Adding an extra neutron may or may not disrupt the strong force that much, and so the half-life and stability of the new isotope can be slightly different than its most stable one.
<span>BaCl2+Na2SO4---->BaSO4+2NaCl
There is 1.0g of BaCl2 and 1.0g of Na2SO4, which is the limiting reagent?
"First convert grams into moles"
1.0g BaCl2 * (1 mol BaCl2 / 208.2g BaCl2) = 4.8 x 10^-3 mol BaCl2
1.0g Na2SO4 * (1 mol Na2SO4 / 142.04g Na2SO4) = 7.0 x 10^-3 mol Na2SO4
(7.0 x 10^-3 mol Na2SO4 / 4.8 x 10^-3 mol BaCl2 ) = 1.5 mol Na2SO4 / mol BaCl2
"From this ratio compare it to the equation, BaCl2+Na2SO4---->BaSO4+2NaCl"
The equation shows that for every mol of BaCl2 requires 1 mol of Na2SO4. But we found that there is 1.5 mol of Na2SO4 per mol of BaCl2. Therefore, BaCl2 is the limiting reagent.</span>
You are given
200 grams of H2O(s) at an initial temperature of 0°C. you are also given the
final temperature of water after heating at 65°C. You are required to get the
total amount of heat to melt the sample. The specific heat capacity, cp, of
water is 4.186 J/g-°C. Let us say that T1 = 0°C and T2 = 65°C. The equation for
heat, Q, is
Q = m(cp)(T2-T1)
Q = 200g(4.186
J/g-°C )(65°C - 0°C)
<u>Q =
54,418J</u>
D. infrared waves.
The infrared waves are hard to detect, so it is hard to detect where the soldiers are at night
