Answer:
0.83 mL
Explanation:
Given data
- Initial concentration (C₁): 12 M
- Final concentration (C₂): 1.0 M
- Final volume (V₂): 10.0 mL
We can calculate the initial volume of HCl using the dilution rule.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 1.0 M × 10.0 mL / 12 M
V₁ = 0.83 mL
The required volume of the initial solution is 0.83 mL.
Answer:
b. 3.66x10²³ atoms of chromium.
Explanation:
First we calculate how many moles are there in 31 grams of chromium, using its molar mass:
- Molar Mass of Chromium = 51 g/mol (This can be found on any periodic table)
- 31 g ÷ 51 g/mol = 0.608 mol
Then we <u>calculate how many atoms are there in 0.608 moles</u>, using <em>Avogadro's number</em>:
- 0.608 mol * 6.023x10²³ atoms/mol = 3.66x10²³ atoms
The correct answer is thus option b. 3.66x10²³ atoms of chromium.
1.39 g HCl
Explanation:
The balanced chemical equation for this reaction is given by
Zn(<em>s</em>) + 2HCl(<em>aq</em>) ---> ZnCl2(<em>aq</em>) + H2(<em>g</em>)
Convert the # of grams of Zn to moles:
1.25 g Zn × (1 mol Zn/65.38 g Zn) = 0.0191 mol Zn
Use the molar ratio to find the # of moles of HCl needed to react completely with the given amount of Zn:
0.0191 mol Zn × (2 mol HCl/1 mol Zn) = 0.0382 mol HCl
Convert this amount to grams:
0.0382 mol HCl × (36.458 g HCl/1 mol HCl) = 1.39 g HCl
The first ionization energy is the energy that the atom lost its first electrons. The energy decrease and the atom is more reactive. So from highest to lowest is Li>Na>K>Rb.
Answer:
Option C = object B by 1 gram per cubic cm.
Explanation:
Given data:
Mass of object A = 12 g
Volume of object A = 8 cm³
Mass of object B = 20 g
Volume of object B = 8 cm³
Densities = ?
Solution:
Density:
Density is equal to the mass of substance divided by its volume.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Symbol:
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
Density of object A:
d = m/v
d = 12 g/ 8 cm³
d = 1.5 g/cm³
Density of object B:
d = m/v
d = 20 g/ 8 cm³
d = 2.5 g/cm³
object b has high density.
