Answer:
1) 0.0025 mol/L.s.
2) 0.0025 mol/L.s.
Explanation:
<em>H₂ + Cl₂ → 2HCl.</em>
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<em>The average reaction rate = - Δ[H₂]/Δt = - Δ[Cl₂]/Δt = 1/2 Δ[HCl]/Δt</em>
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<em>1. Calculate the average reaction rate expressed in moles H₂ consumed per liter per second.</em>
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The average reaction rate expressed in moles H₂ consumed per liter per second = - Δ[H₂]/Δt = - (0.02 M - 0.03 M)/(4.0 s) = 0.0025 mol/L.s.
<em>2. Calculate the average reaction rate expressed in moles CI₂ consumed per liter per second.</em>
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The average reaction rate expressed in moles Cl₂ consumed per liter per second = - Δ[Cl₂]/Δt = - (0.04 M - 0.05 M)/(4.0 s) = 0.0025 mol/L.s.
Answer: 72 grams of 
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number 
of particles.
To calculate the number of moles, we use the equation:
Putting in the values we get:
According to stoichiometry:
1 mole of 
requires 5 moles of oxygen
0.45 moles of require= 
moles of oxygen
Mass of 
72 grams of are needed to completely burn 19.7 g
Answer:
To have the electronic configuration equal to 1s²2s²2p⁶3s²3p⁶4s²3d⁷, the chemical element must have an electrical charge equal to 27, that is, it must have 27 electrons, such as Cobalt (Co), for example.
Explanation:
The electronic configuration shown in the question above is known as the Linus Pauling distribution and represents the energy sub-levels that an electrically charged atom can have in relation to the amount of electrons it has.
The layers sub-levels are presented in the following order 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹º 4p⁶ 5s² 4d¹º 5p⁶ 6s² 4f14 5d¹º 6p⁶ 7s² 5f14 6d¹º 7p⁶. Where the small numbers represent the number of electrons in each sub-level and the large numbers represent the layers of electronic distribution.
Accordingly, we can see that an atom that has the configuration 1s²2s²2p⁶3s²3p⁶4s²3d⁷ has 27 electrons, like Cobalt.
