The first statement (Matter is neither created nor destroyed) is correct.
The second statement would violate the law of conservation of mass (I will refer to this as LCM), as it would mean matter can "flow" into the universe, but not out, meaning the total matter will never be less than it was before.
The third statement violates LCM because it means matter is created during a reaction, which is not true.
The last statement violates LCM because it means matter is lost during a reaction, which is not true.
 
        
             
        
        
        
Ca(OH)₂: strong base
pOH = a . M
a = valence ( amount of OH⁻)
M = concentration
Ca(OH)₂ ⇒ Ca²⁺ + 2OH⁻ (2 valence)
so:
pOH = 2 x 0.005
pOH = 0.01
pH = 14 - 0.01 = 13.99
 
        
             
        
        
        
The chemical formula for sodium and sulfur is Na2S I believe...
        
             
        
        
        
Given:
ΔV = 5 - 1.48 L = 3.52 L = 0.00352 m³, th chane in volume
p = 0.818 atm = 0.819*101325 Pa = 82985.2 Pa
By definition, the work done is

Answer: 292.1 J
 
        
             
        
        
        
Answer:
.259 g 
Explanation:
PV = nRT 
n = PV / RT 
= .986 x 0.144 / .082 x 293.6 
= .005897 moles 
= .005897 x 44 g 
= .259 g