Answer:
The density of block is 2 g/mL.
Explanation:
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.
Given data:
mass of block = 12 g
volume = 6 mL
density = ?
Now we will put the values in the formula,
d= m/v
d = 12 g/ 6 mL
d = 2 g/mL
so, the density of block is 2 g/mL .
<u>Answer:</u> The correct option is
<u>Explanation:</u>
A catalyst is defined as the chemical species that increases the reaction rate but does not participate in it and is left behind after the completion.
A homogeneous catalyst is one that is present in the same phase as the reactants and products.
A heterogeneous catalyst is one that is present in different phase as that of reactants and products.
For the given chemical reaction:

As all the reactants and products are in gaseous state so, the homogeneous catalyst must also be in the gaseous state only.
Hence, the correct option is 
They're based on the results of your testing.
Answer:
If you speak a futureless language, you will speak about time identically meaning you will feel as they are identical, it increases your propensity to save.
Explanation:
hope this helps you :)
Mass using grams because of the balance scale is evenly weighted not from springs and gravity like a normal scale.