I am using a graduated cylinder to measure the volume of my keys . Before I place the keys in , the volume is 35mL. After I place the keys in , the volume is 64 mL. What is the volume of my keys ?

29 mL

Explanation:

Step 1: Given data

Volume of water inside the graduated cylinder: 35 mL

Volume of the water after placing the keys: 64 mL

Step 2: Calculate the volume of the keys

The rise in the level of the water is due to the volume of the keys. We can find the volume of the keys by subtracting the final volume to the initial volume.

V(keys) = 64 mL - 35 mL = 29 mL

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g