One mole of a substance is equal to 6.022 × 10²³ units of that substance (such as atoms, molecules, or ions). The number 6.022 × 10²³ is known as Avogadro's number or Avogadro's constant.
Answer:
Density, 
Explanation:
Mass of a marble slab is 38.6 kg 38600 grams
The dimensions of the marble is 17 cm×23 cm×4 cm
We need to find its density. Mass per unit volume equals density. So,
So, the density of the marble slab is 
Step 1: Write Imbalance Equation
CH₃CHO + O₂ → CO₂ + H₂O
Step 2: Balance Carbon Atoms:
There are 2 carbon atoms at reactant side and one at product side. So multiply CO₂ with 2 to balance them. i.e.
CH₃CHO + O₂ → 2 CO₂ + H₂O
Step 3: Balance Hydrogen Atoms:
There are 4 hydrogen atoms at reactant side and 2 Hydrogen atoms at product side. So, multiply H₂O by 2 to balance Hydrogen on both sides. i.e.
CH₃CHO + O₂ → 2 CO₂ + 2 H₂O
Step 4: Balance Oxygen Atoms:
There are 3 Oxygen atoms at reactant side and 6 Oxygen atoms at product side. In order to balance them multiply O₂ on reactant side by 2.5 (5/2). i.e
CH₃CHO + 5/2 O₂ → 2 CO₂ + 2 H₂O
Step 6: Eliminate Fraction:
Multiply overall equation by 2 to eliminate fraction. i.e.
2 CH₃CHO + 5 O₂ → 4 CO₂ + 4 H₂O
-1 charge = the atom has gained one electron
9+1=10
It depends on the pH if the base. but normally light colors are for bases example blue green etc
