Answer:
296.448 g
Explanation:
Density:
we know that density of an object can be measured by dividing its mass to its 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.
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
Given data:
volume= 1.2 cm x 4.00 cm x 3.20 cm =15.36 cm3
density= 19.3 g/cm3
mass=?
Now we will put the values in the formula,
d=m/v
d x V= m
m = 15.36 cm3 x 19.3 g/cm3
m=296.448 g
so the mass of block of gold is 296.448 g
Answer is: 3,4
Chemical reaction: HNO₂ + NaOH → NaNO₂ + H₂O.
c₀(HNO₂) = 1,2 M = 1,2 mol/dm³.
c₀(NaNO₂) = 0,8 M = 0,8 mol/dm³.
V₀(HNO₂) = V₀(NaNO₂) = 1 dm³ = 1 L.
c₀(NaOH) = 0,5 M = 0,5 mol/dm³.
n₀(HNO₂)= 1,2 mol/dm³ · 1 dm³ = 1,2 mol.
n₀(NaNO₂) = 0,8 mol/dm³ · 1 dm³ = 0,8 mol.
V(NaOH) = 400 mL · 0,001 dm³/mL = 0,4 dm³.
n₀(NaOH) = c₀(NaOH) · V₀(NaOH).
n₀(NaOH) = 0,5 mol/dm³ · 0,4 dm³ = 0,2 mol.
n(HNO₂) = 1,2 mol - 0,2 mol = 1 mol.
n(NaNO₂) = 0,8 mol + 0,2 mol = 1 mol.
c(HNO₂) = 1 mol ÷ 1,4 dm³ = 0,714 mol/dm³.
c(NaNO₂) = 1 mol ÷ 1,4 dm³ = 0,714 mol/dm³.
pH = pKa + log (c(HNO₂) / c(NaNO₂)).
pH = 3,4 + log (0,714 mol/dm³ / 0,714 mol/dm³) = 3,4.
Answer:
7. genetics because hereditary is not the study of hereditary.
8. is hereditary because it is the study of how things pass on to next generation what is inherited.
Answer: The statement the 
shell holds a minimum number of 
electrons is true.
Explanation:
The alphabet 'n' denotes the principal quantum number whose value can be equal to 1, 2, 3, and so on but can never be zero.
Basically, 'n' is the number of shell of an atom and total number of orbitals present in a shell is 
.
Each orbital can hold up to a maximum of wo electrons. Hence, the shell can hold a minimum number of electrons.
Thus, we ca conclude that the statement the shell holds a minimum number of electrons is true.
The mass percentage of water (H₂O) in cadmium chloride tetra hydratesolution is equal to the 28.2%.
<h3>How do we calculate mass percentage?</h3>
Mass percentage of any substabce present in any solution will be calculated as:
Mass percent = (Mass of substance/Total mass of solution)×100%
According to the question,
Mass of water (H₂O) = 18.02 g/mol
Mass of solvent (CdCl₂.4H₂O) = 183.32 + 4(18.02) = 255.4 g/mol
On putting values, we get
Mass percent = (18.02 / 255.4) × 100% = 28.2%
Hence mass percent of water is 28.2%.
To know more about mass percent, visit the below link:
brainly.com/question/13896694
