Answer:
0.693 (you can round it up if you want to)
Explanation:
Density= mass ÷ volume
54.2 ÷ 78.1 = 0.693
I hope this helped☺
 
        
             
        
        
        
Answer:
Yes!
Explanation:
I think It would be fun!, Going thought space going from planet to planet. once i get back to earth i can make a document about my time in space. 
 
        
             
        
        
        
Answer:
its atomic number will be 3 and it's mass number will be 7. it is lithium
 
        
             
        
        
        
Protons: charge +1, have a mass of 1 and are found in the nucleus 
Neutrons: charge 0, have a mass of 1 and are found in the nucleus
Electrons: charge -1, have a mass of 1/840 and are found on the outside of the nucleus 
hope that helps 
        
             
        
        
        
To calculate the <span>δ h, we must balance first the reaction: 
NO + 0.5O2 -----> NO2
Then we write all the reactions,
2O3 -----> 3O2    </span><span>δ h = -426 kj        eq. (1)
O2 -----> 2O    </span><span>δ h = 490 kj             eq. (2)
NO + O3 -----> NO2 + O2    </span><span>δ h = -200 kj          eq. (3)
We divide eq. (1) by 2, we get
</span>O3 -----> 1.5O2    δ h = -213  kj             eq. (4)
Then, we subtract eq. (3) by eq. (4) 
NO + O3 ----->  NO2 + O2   δ h = -200 kj
-       (O3 -----> 1.5 O2         δ h = -213  kj)
NO -----> NO2 - 0.5O2        δ h = 13  kj               eq. (5)
eq. (2) divided by -2. (Note: Dividing or multiplying by negative number reverses the reaction)
O -----> 0.5O2  <span>δ h = -245  kj         eq. (6)
</span>
Add eq. (6) to eq. (5), we get
NO -----> NO2 - 0.5O2        δ h = 13  kj 
+  O -----> 0.5O2                 δ h = -245  kj
NO + O ----> NO2               δ h = -232 kj
<em>ANSWER:</em> <em>NO + O ----> NO2               δ h = -232 kj</em>