Answer:
1280J are required.
Explanation:
Heat of fusion is defined as the amount of heat required to change its state from liquid to solid at its melting point at constant pressure.
As heat of fusion of gold is 64J/g, there are required 64J to melt 1g of gold at its melting point. The energy required to melt 20g is:
20g * (64J/g) =
1280J are required
Answer:


Explanation:
<u>First mixture</u>:
40 wt% methanol - 60 wt% water 200 kg


<u>Second mixture</u>:
70 wt% methanol - 30 wt% water 150 kg


Final mixture:




If, the compositions are constant, the only variables are the mass of each mixture used in the final one, so there can be only one independent balance.
Answer: Lexington and Concord
Explanation: The British were trying to find weapons and could not find them.
The water from the lake must first evaporate from the liquid state to the gaseous state and then condense in the air to form vapors.
The water molecules absorb energy while evaporating and release it when condensing. Their motion gets faster when they are evaporating and slows back down upon condensation.