Answer:
9000 BC
Explanation:
Although various copper tools and decorative items dating back as early as 9000 BCE have been discovered, archaeological evidence suggests that it was the early Mesopotamians who, around 5000 to 6000 years ago, were the first to fully harness the ability to extract and work with copper.
They are moving away from each other
Answer:
The final temperature is 31.95° C.
Explanation:
Given that,
Initial temperature of a sample of chloroform, 
Mass of chloroform, m = 150 g
It absorbs 1 kJ of heat, Q = 10³ J
The specific heat of chloroform, c = 00.96 J/gºC
We need to find the final temperature. The heat absorbed by an object in terms of specific heat is given by :
So, the final temperature is 31.95° C.
Answer:
Answer: B. Water condenses to form clouds.
Explanation:
When the moisture condenses, this results in the release of energy. The energy causes the air to be warm and results in the rise of air in the upper atmosphere. This process results in the instability in the atmosphere and cumulonimbus clouds are formed. These clouds support lightening during a thunderstorm.
Answer:25,06 kJ of energy must be added to a 75 g block of ice.
ΔHfusion(H₂O) = 6,01 kJ/mol.
T(H₂O) = 0°C.
m(H₂O) = 75 g.
n(H₂O) = m(H₂O) ÷ M(H₂O).
n(H₂O) = 75 g ÷ 18 g/mol.
n(H₂O) = 4,17 mol.
Q = ΔHfusion(H₂O) · n(H₂O)
Q = 6,01 kJ/mol · 4,17 mol
Q = 25,06 kJ.
Explanation:
