We subtract the enthalpies of the reactants from that of the products:

Since this is < 0, this is an exothermic reaction.
Use the equation d=m/v
your mass or "m" is 78 g
your volume or "v" is 60mL
if you plug those values into the equation it will look like this:
d=78/60
d=1.3g/mL should be what you come up with
Answer:
C- A proton has about the same mass as a neutron .
Explanation:
In an atom such as a carbon atom, the masses of the proton and neutrons are the same.
The mass of the electrons is very negligible.
- Protons are the positively charged particles in an atom
- Neutrons do not carry any charges
- Both protons and neutrons have similar masses.
- They contribute the bulk of the mass of the atom.
- The electrons carry negative charges and they have negligible masses.
The mass of protons and neutrons are similar.
Reduction reactions are those reactions that reduce the oxidation number of a substance. Hence, the product side of the reaction must contain excess electrons. The opposite is true for oxidation reactions. When you want to determine the potential difference expressed in volts between the cathode and anode, the equation would be: E,reduction - E,oxidation.
To cancel out the electrons, the e- in the reactions must be in opposite sides. To do this, you reverse the equation with the negative E0, then replacing it with the opposite sign.
Pb(s) --> Pb2+ +2e- E0 = +0.13 V
Ag+ + e- ---> Ag E0 = +0.80 V
Adding up the E0's would yield an overall electric cell potential of +0.93 V.
Lithium is atomic number 3, so it has valency 1
While, Bromine is atomic number 35, and has valency 1
Lithium has an extra electron while Bromine need an electron, since they both need and have one electron, the form
LiBr (Lithium Bromide) where Li is +ve charged and Br is -ve charged
Happy to help :)