A graph titled Position versus time for with horizontal axis time (seconds) and vertical axis position (meters). The line runs in 3 straight segments from 0 seconds 0 meters to 4 seconds 12 meters to 6 seconds 12 meters to 12 seconds 0 meters. Based on the graph, describe what is happening between 4 and 6 seconds.

The object is moving away from the start at a constant speed.
The object is not moving.
The object is returning to the start at a constant speed.
The object is changing speed.

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

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.