<u>Answer:</u>
a. Oxidising agent: Cl₂
b. Reducing agent: NaBr
c. Oxidised: NaBr
d. Reduced: Cl₂
e. Oxidation numbers before reaction: Cl= 0, Na= +1, Br= -1
f. Oxidation numbers after reaction: Cl= -1, Na= +1, Br= 0
<u>Explanation:</u>
Oxidising agents reduces themselves, oxidising other elements/compounds.
Reducing agents oxidise themselves, reducing other elements/compounds.
Oxidation is the <u>loss</u> of electrons or an <u>increase</u> in oxidation number.
Reduction is the <u>gain</u> of electrons or <u>decrease</u> in oxidation number.
The correct answer is a descriptive investigation.
An investigation which does not involve hypotheses called descriptive investigation.
Hypotheses are termed as scientific hypotheses and require that one can test it. In hypothesis, previous observation can not satisfactorily be explained with an available scientific theory.
Working hypotheses are being proposed for further research.
Answer:
Number of moles = 0.92 mol
Explanation:
Given data:
Mass of CaSO₄ = 125 g
Number of moles of CaSO₄ = ?
Solution:
Formula:
Number of moles = mass/ molar mass
Molar mass of CaSO₄:
Molar mass of CaSO₄ = 40 + 32+ 16×4
Molar mass of CaSO₄ = 40 + 32+ 64
Molar mass of CaSO₄ = 136 g/mol
Number of moles:
Number of moles = mass/ molar mass
Number of moles = 125 g/ 136 g/mol
Number of moles = 0.92 mol
That is correct c
Explanation
The atoms of hydrogen that are present in 7.63 g of ammonia(NH3)
find the moles of NH3 =mass/molar mass
7.63 g/ 17 g/mol = 0.449 moles
since there is 3 atoms of H in NH3 the moles of H = 0.449 x 3 = 1.347 moles
by use of 1 mole = 6.02 x10^23 atoms
what about 1.347 moles
= 1.347 moles/1 moles x 6.02 x10^23 atoms = 8.11 x10^23 atoms of Hydrogen
