Answer:
2. Chemical reactions changes occur when the bonds between atoms in a molecule are created or destroyed.
3. When you reach your its boiling point, the molecules in liquid have enough energy to become a gas.
4. When you have a solid with more than one type of compound, it is called a mixture.
5. A Crystal is a form of solid where the atoms are arranged is a very specific order.
6. If you have different types of molecules dissolved in a liquid, it is called a solution
Answer:
1. Density of Metal = 4.40g/cm³
2. Density of Liquid = 0.77568g/cm³
Explanation:
1.
Given
Initial Volume of Water = Vi = 21.27mL
Volume of Water = VF = 24.78 mL
Mass of Sphere= 15.45 g
Density = Mass/Volume
Change in Volume = 24.78 - 21.27 = 3.51 mL
Density = 15.45/3.51
Density = 4.40g/ml
1ml = 1cm³
So, density = 4.40/cm³
2.
Initial Mass of Beaker = Mb = 32.4257g
Final Mass of Beaker = Mf = 40.1825 g
V = 10 mL
Density = D = ?
Change in Mass =: MF – MI= 40.1825 – 32.4257 = 7.7568 g
Density = Mass/Volume
Density = 7.7568g/10mL
Density = 0.77568g/mL
1mL = 1cm³
So, density = 0.77568g/cm³
Answer:
a. 0.40
b. 0 .62 mol HCl
c. 0.29 mol HCl
Explanation:
Lets call A⁻ the molar concentration of the weak base A⁻, and HA the acid concentration of HA
a. pH = pKa
from Henderson-Hasselbach equation for buffer solutions:
pH = pKa - log(( A⁻/HA))
we can see that pH = Pka when the log(( A⁻/HA)) is 0 which is the case for the log 1 hence
A⁻ =HA and
Ka= H⁺ x A ⁻/ HA
Now for the equilibrium of the weak acid we have
R HA================== H⁺ + A⁻
Initially 0.80 0 0
Change -x + x + x
Equilibrium 0.80 - x x x
Since x = A⁻ and HA = 0.80- x
x/ (0.80-x) =1
x = 0.80 -x 2x = 0.80
x = 0.40
b. From the Henderson-Hasselbach eqn:
pH = pKa - log ((A⁻/HA))
4.20-4.74 = log ((0 .80-x)/x) (the negative log of A⁻/HA is the same as log HA/A⁻)
-0.54 = log ((0.80-x)/x)
0.29 = (0.80-x)/x
0.29 x = 0.80 - x
1.29 x = 0.80 moles HCL
x = 0.62
c. pH= 5.00
Using the same relationships as in b.
5.00-4.74 = log ((0.80-x)/x)
1.80 =( 0.80 - x) /x
2.8 x = 0.80
x = 0.29
0.29 mol HCl needed
Volume of a cube is length times width times height so do 125 times 37 times 68
Answer:
4) a mixture.....................