Answer:
A. Position B.
Explanation:
In the summer the northern hemisphere is closer to the Sun so it's Position B.
Answer:
eight oxygen atoms
Explanation:
This formula shows that in one mole of this compound, there are 3 moles of Ca atoms that combine with 2 moles of the PO4(phosphate) groups, which gives a total of 2 moles of P atoms and 8 moles of 0 atoms.
Answer:
The fraction of water body necessary to keep the temperature constant is 0,0051.
Explanation:
Heat:
Q= heat (unknown)
m= mass (unknown)
Ce= especific heat (1 cal/g*°C)
ΔT= variation of temperature (2.75 °C)
Latent heat:
ΔE= latent heat
m= mass (unknown)
∝= mass fraction (unknown)
ΔHvap= enthalpy of vaporization (539.4 cal/g)
Since Q and E are equal, we can match both equations:
Mass fraction is:
∝=0,0051
Answer:
Explanation:
The Lanthanides were first discovered in 1787 when a unusual black mineral was found in Ytterby, Sweden. This mineral, now known as Gadolinite, was later separated into the various Lanthanide elements. In 1794, Professor Gadolin obtained yttria, an impure form of yttrium oxide, from the mineral.
