Answer:
Concentration of the resulting solution = 2.04 M
Explanation:
<u>Data:</u>
M1 = 5.10 M
V1 = 200.0 mL
V2 = 500.0 mL
M2 = ?
By modifying the volume of solution, keeping the amount of solute constant, the concentration changes. To perform the calculations, the equation will be:

Where M1 is the initial concentration of the solution, M2 the final concentration and V is the value of the volumes of the initial and final solution.
Clearing the value of M2 from the equation and replacing the values we have:

The energy produced by burning : -32.92 kJ
<h3>Further explanation</h3>
Delta H reaction (ΔH) is the amount of heat change between the system and its environment
(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)
The enthalpy and heat(energy) can be formulated :

The enthalpy of combustion of naphthalene (MW = 128.17 g/mol) is -5139.6 kJ/mol.
The energy released for 0.8210 g of naphthalene :

Answer:
Number of moles = 0.057 × 10⁻⁷ mol
Explanation:
Given data:
Mass of SiO₂ = 3.4 × 10⁻⁷ g
Number of moles = ?
Solution:
Number of moles = mass/molar mass
Molar mass of SiO₂ = 60 g/mol
by putting values,
Number of moles = 3.4 × 10⁻⁷ g / 60 g/mol
Number of moles = 0.057 × 10⁻⁷ mol
We could use solar power, wind power, geothermal power, hydroelectric power, or nuclear power. There are probably more but this is what I can think of off the top of my head. I hope this helps. Let me know if anything is unclear.