Answer:
In both cases, the gas evolved is H2. When calcium reacts with water the heat evolved is not suffcient for hydrogen to catch fire. On the other hand, sodium metal reacts with water violently and in this case a lot of heat is evolved which is sufficient for hydrogen to catch fire.
Explanation:
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Answer:
Reflection involves a change in direction of waves when they bounce off a barrier; refraction of waves involves a change in the direction of waves as they pass from one medium to another; and diffraction involves a change in direction of waves as they pass through an opening or around a barrier in their path.
Explanation:
https://www.physicsclassroom.com/class/waves/Lesson-3/Reflection,-Refraction,-and-Diffraction#:~:text=Diffraction%20of%20Waves-,Reflection%20involves%20a%20change%20in%20direction%20of%20waves%20when%20they,a%20barrier%20in%20their%20path.
Answer:
Mechanical Energy to Thermal Energy
When you strike a match, it moves through the air until it rubs against a surface. The rubbing produces the heat required to light the match. This is a transformation from mechanical energy to thermal (heat) energy.
Explanation:
Answer:
If you are given a chemical equation and specific amounts for each reactant in grams, you have to follow these steps, in order, to determine how much product can possilby be made:
1. Convert each reactant into moles of the product.
2. Determine which reactant is the limiting reactant.
3. Convert the moles of product, from the limiting reactant, to grams.
Explanation:
Answer:
16974J of energy are required
Explanation:
The energy required is:
* The energy to heat solid water from -15°C to 0°C using:
q = m*S*ΔT
* The energy to convert the solid water to liquid water:
q = dH*m
* The energy required to increase the temperature of liquid water from 0°C to 75°C
q = m*S*ΔT
The first energy is:
q = m*S*ΔT
<em>m = Mass water = 25g</em>
<em>S is specific heat of ice = 2.03J/g°C</em>
<em>ΔT is change in temperature = 0°C - (-15°C) = 15°C</em>
q = 25g*2.03J/g°C*15°C
q = 761.3J
The second energy is:
q = dH*m
<em>m = Mass water = 25g</em>
<em>dH is heat of fusion of water = 80cal/g</em>
q = 80cal/g*25g
q = 2000cal * (4.184J/1cal) = 8368J
The third energy is:
q = m*S*ΔT
<em>m = Mass water = 25g</em>
<em>S is specific heat of water= 4.184J/g°C</em>
<em>ΔT is change in temperature = 75°C-0°C = 75°C</em>
q = 25g*4.184J/g°C*75°C
q = 7845J
The energy is: 7845J + 8368J + 761J =
16974J of energy are required
