Ar (Cl) = 34.969 * 75.78/ 100 + 36.966 * 24.22/ 100= 35, 45 :)
Answer:
Any element placed in a flame will change its color. Atoms are made of positively charged nuclei, about which negatively charged electrons move according to the laws of quantum mechanics. Quantum mechanics constrains them to appear in various distinct patterns, called orbitals. (Orbitals are a lot like planetary orbits, but blurrier, so that you're never quite sure just where the electrons are.)
Left on their own, the electrons of an atom tend to relax into orbitals that leave the atom with the lowest possible energy--its ground state. Putting atoms into a flame, though, adds energy to the looser electrons farthest from the nucleus and pushes them into other orbitals. Eventually, these excited electrons drop back to where they ought to be, and in so doing, they release the energy they stored up as particles of light, called photons.
Explanation:
Answer:
21 kJ
Step-by-step explanation:
The formula for the heat q is
q = mCΔT
<em>Data:
</em>
m = 200 g; C = 4.184 J·°C⁻¹g⁻¹
T₁ = 50. °C; T₂ = 25 °C
<em>Calculations:
</em>
ΔT = T₂ - T₁
ΔT = 25 – 50.
ΔT = -25 °C
q = 200 × 4.184 × (-25)
q = -21 000 J Convert to kilojoules
q = -21 kJ
The negative sign shows that energy is released, so the water has released 21 kJ of energy.
Answer:
Mass released = 8.6 g
Explanation:
Given data:
Initial number of moles nitrogen= 0.950 mol
Initial volume = 25.5 L
Final mass of nitrogen released = ?
Final volume = 17.3 L
Solution:
Formula:
V₁/n₁ = V₂/n₂
25.5 L / 0.950 mol = 17.3 L/n₂
n₂ = 17.3 L× 0.950 mol/25.5 L
n₂ = 16.435 L.mol /25.5 L
n₂ = 0.644 mol
Initial mass of nitrogen:
Mass = number of moles × molar mass
Mass = 0.950 mol × 28 g/mol
Mass = 26.6 g
Final mass of nitrogen:
Mass = number of moles × molar mass
Mass = 0.644 mol × 28 g/mol
Mass = 18.0 g
Mass released = initial mass - final mass
Mass released = 26.6 g - 18.0 g
Mass released = 8.6 g
No. Changing of color is a physical change.