Answer:
When water freezes, water molecules form a crystalline structure maintained by hydrogen bonding. Solid water, or ice, is less dense than liquid water. Ice is less dense than water because the orientation of hydrogen bonds causes molecules to push farther apart, which lowers the density.
The answers to your questions:
1: B.
2: True
Answer:
Mass, m = 7.97 grams
Explanation:
We have,
Initial temperature was 34 degrees Celsius
Heat produced in it is 100 calories of heat
The specific heat capacity of water is 4.18 J/g °C
The heat produced due to change in temperature is given by :
m is mass of water in grams
So, 7.97 grams of water is required to produce heat of 2200 joules.
Answer:
computer model
Explanation:
Computer models are cheaper to set up than alternative methods that could be used to predict what will happen in a system, ex. building a prototype. Other benefits include being able to: make alterations and quickly see the outcomes.
Answer:
1, 2, 4
Explanation:
The primitive cubic unit cell has eight corners, and each corner is shared with 8 cubic unit cells. Therefore since we have one atom at each corner, we will have:
8 corner x 1 atom/8 corner = 1 atom
There is then the equivalent of one atom per unit cell in the primitive cubic cell.
For the body-centered cubic unit cell, we have 8 corners again shared each by 8 lattices as in the simple cubic plus we have one atom in the center of the cubic lattice. Therefore, the number of atoms in the body -centerd unit cell is two:
8 corner x 1 atom/8 corner = 1 atom
+
1 atom in the center
= 2 atoms/ unit cel
For the face-centerd cubic again we have 8 atoms in the corners shared by 8 lattices, plus 1 atom in each of the faces shared by two unit cells:
8 corner x 1/8 atom/corner + 6 faces x 1 atom/face = 4 atoms/unit cell