Answer:
a. 1,2,and 3.
Explanation:
When something turns liquid, e.g. metal, you need to heat it. When something turns gas, e.g. water, you need to heat it. And when something goes directly from solid to gas, e.g. dry ice, carbon dioxide, you need to add heat to it. hope this helps! Please mark brainiest.
Answer:
BF3
Explanation:
For this question, you need to use the number of valence electrons present in each element. Boron is in group 3/13 on the periodic table so you know it has 3 valence electrons while Fluorine is in group 7/17 so it has 7 valence electrons. These elements are both covalent so they will share electrons. All elements in the first three rows want to reach either have 8 valence electrons or zero valence electrons depending on whichever is easier. When B and F interact each Fluorine will only want to take one electron, but Boron wants to get rid of all 3 electrons, so it will bond with 3 Fluorine to get rid of all its valence electrons.
I hope this helps.
The air pressure inside the can is lower compared to that of outside air pressure.
Explanation:
- In general, the air pressure of an already opened can will be the same as the outside pressure.
- Since the can is evacuated and remain as vacuum, so there will be no pressure difference in it.
- If the can opens, air inside the can push the top and escapes to the outside.
- This is due to high pressure experienced outside the can compare to that of lower pressure inside the can and this may even cause can to collapse itself.
Answer:
Density of unit cell ( rhodium) = 12.279 g/cm³
Explanation:
Given that:
The radius (r) of a rhodium atom = 135 pm
The atomic mass of rhodium = 102.90 amu
For a face-centered cubic unit cell,
where;
a = edge length.
Making "a" the subject of the formula:
a = 381.8 pm
to cm, we get:
a = 381.8 × 10⁻¹⁰ cm
However, recall that:
where;
mass of unit cell = mass of atom × numbers of atoms per unit cell
Also;
Recall also that number of atoms in a unit cell for a face-centered cubic = 4
So;
mass of unit cell = 6.83380375 × 10⁻²² g
Density of unit cell ( rhodium) = 12.279 g/cm³
