Answer:
In our modern periodic table, the horizontal rows are known as periods , and the elements belonging to same period have same numbers of shells .
for example :
lithium, beryllium , boron , carbon , nitrogen , oxygen, fluorine and neon are in same period and have total 2 shells .
Answer:
make contact with the heat source
Explanation:
Answer:
mass of sodium reacted is 184.1 g
Explanation:
mass Na = X = ?
∴ mass NaCl = 468 g
∴ mass Cl = 0.248 g
∴ molar mass NaCl = 58.44 g/mol
∴ atomic mass Cl = 35.453 a.m.u
∴ atomic mass Na = 22.989 a.m.u
⇒ moles Na = (X gNa)*(mol Na/22.989 g) = X/22.989 mol Na
⇒ mass NaCl = (X/22.989 mol Na)*(mol NaCl/mol Na)*(58.44 gNaCl/mol NaCl) = 468 g NaCl
clearing "X":
⇒ ((58.44)(X))/(22.989) = 468 g
⇒ X = 184.1 g = mass Na reacted
The amount of heat lost by the copper is 2402.4 J.
To Calculate the amount of heat lost, we use the formula below.
<h3>Formula:</h3>
- Q = cm(t₂-t₁)................. Equation 1
<h3>Where:</h3>
- Q = Amount of heat lost
- c = specific heat capacity of copper
- m = mass of copper
- t₂ = Final temperature
- t₁ = Initial temperature
From the question,
<h3>Given:</h3>
- m = 78 g
- c = 0.385 J/g°C
- t₂ = 120°C
- t₁ = 40°C
Substitute these values into equation 1.
- Q = 78(0.385)(120-40)
- Q = 2402.4 J
Hence, The heat lost by the copper is 2402.4 J
Learn more about heat here: brainly.com/question/13439286
