Predict the sign of ΔS° for 2NO2(g) LaTeX: \longrightarrow⟶ N2O4(g) CaCO3(s) + 2HCl(aq) LaTeX: \longrightarrow⟶ CaCl2(aq) + H2O(l) +CO2(g) Ag+(aq) + Cl-(aq) LaTeX: \longrightarrow⟶ AgCl(s)

a. : is negative

b. : is negative

c. : is negative

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from  an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa

a)  

In this reaction 2 moles of gaseous reactants are converting to 1 mole of gaseous products. The randomness will decrease and hence entropy will also decrease. Thus is negative.

b)

In this reaction solid reactants are converting to aqueous products. The randomness will increase and hence entropy will also increase. Thus is positive.

c)

In this reaction aqueous reactants are converting to solid products. The randomness will decrease and hence entropy will also decrease. Thus is negative

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

the answer is b & c i believe : )