The formula is density = mass / Volume
density = ?
mass = 21 g
Volume = 9 mL
d = m / V
d = 21 g / 9 mL
d = 2.3 g/mL
Hope this help!
Answer:
The correct answer is 0.92 g
Explanation:
The density is defined as the mass per unit of volume:
Density= mass/volume
From the data provided:
volume= 5.4 L
density= 0.17 g/L
Thus, to calculate the mass of helium:
mass= density x volume = 0.17 g/L x 5.4 L= 0.918 g ≅ 0.92 g
Answer:

Explanation:
Assume the reaction is the combustion of propane.
Word equation: propane plus oxygen produces carbon dioxide and water
Chemical eqn: C₃H₈(g) + O₂(g) ⟶ CO₂(g) + H₂O(g)
Balanced eqn: C₃H₈(g) + 5O₂(g) ⟶ 3CO₂(g) + 4H₂O(g)
(a) Table of enthalpies of formation of reactants and products

(b)Total enthalpies of reactants and products

ΔᵣH° is negative, so the reaction is exothermic.
To solve this we use the
equation,
M1V1 = M2V2
where M1 is the concentration of the stock solution, V1 is the
volume of the stock solution, M2 is the concentration of the new solution and
V2 is its volume.
2.5 M x V1 = 1.0 M x .250 L
<span>V1 = 0.10 L or 100 mL of the 2.5 M HCl solution is needed
Hope this helps.</span>
Answer:
your answer would be the last one gold