Answer:
<em>Someone probably touched chemicals and got hurt / burnt</em>
Explanation:
<em>Got asked this question a while back</em>
Answer:
The concentration the student should write down in her lab is 2.2 mol/L
Explanation:
Atomic mass of the elements are:
Na: 22.989 u
S: 32.065 u
O: 15.999 u
Molar mass of sodium thiosulfate, Na2S2O3 = (2*22.989 + 2*32.065 + 3*15.999) g/mol = 158.105 g/mol.
Mass of Na2S2O3 taken = (19.440 - 2.2) g = 17.240 g.
For mole(s) of Na2S2O3 = (mass taken)/(molar mass)
= (17.240 g)/(158.105 g/mol) = 0.1090 mole.
Volume of the solution = 50.29 mL = (50.29 mL)*(1 L)/(1000 mL)
= 0.05029 L.
To find the molar concentration of the sodium thiosulfate solution prepared we use the formula:
= (moles of sodium thiosulfate)/(volume of solution in L)
= (0.1090 mole)/(0.05029 L)
= 2.1674 mol/L
It is either a proton or a neutron . B
<h3>
How to identify the particle</h3>
The particle labeled with an X is a neutral atom or a proton which is symbolically represented as :
AZX
where,
Z = atomic number of the element and is known as the number of protons and number of electron (in the particle)
A = Mass number of the element which is represented as the sum of the protons and neutrons (in the nucleus)
Thus, the statement that best identifies the particle X is that it is either a proton or a neutron
Learn more about mass number here:
brainly.com/question/1805828
#SPJ1