Answer:
Na ·
Explanation:
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In this case, since the Lewis dot structure of any element illustrates the number of valence electrons at the outer shell; we can set up the electron configuration of sodium to obtain:
We can see there is only one valence electron, for that reason the Lewis dot structure is:
Na ·
Whereas the dot represents the valence electron.
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Answer:
First, balance the half-reactions
Second, equalize the electrons
Third,add two reaction equations to get final answer
Explanation:
For example
H₂C₂0₄ + MnO⁻₄ ---------->CO₂+Mn²⁺
(i) Balancing the half reactions
H₂C₂O₄-------->2CO₂+2H⁺+2e⁻
5e⁻ +8H⁺+MnO₄⁻----------->Mn²⁺+4H₂O
(ii)
Equalizing the electrons
5H₂C₂O₄--------->10CO₂+10H⁺+10e⁻ ---here there is a factor of 5
10e⁻+16H⁺+2MnO₄⁻--------->2Mn²⁺+8H₂O -----here there is a factor of 2
(iii)
Add the two where electrons and some Hydrogen ions will cancel out
5H₂C₂O₄+6H⁺+2MnO₄⁻---->10CO₂+2Mn²⁺+8H₂O
We know that there are 100 cm in 1 m, so we can use this to convert to meters:
Therefore we know that 
cm is equal to 2.41 m.
Answer:
B.) 129.9 grams
Explanation:
To find the mass, you need to use the following equation:
Q = mcΔT
In this equation,
-----> Q = energy (J)
-----> m = mass (g)
-----> c = specific heat (J/g°C)
-----> ΔT = change in temperature (°C)
The specific heat of copper is 0.385 J/g°C. Knowing this, you can plug the given values into the equation and simplify to isolate "m".
Q = mcΔT <----- Equation
5000 J = m(0.385 J/g°C)(200 °C - 100 °C) <----- Insert values
5000 J = m(0.385 J/g°C)(100) <----- Subtract
5000 J = m(38.5) <----- Multiply 0.385 and 100
129.9 = m <----- Divide both sides by 38.5
