Answer:
c. 3
Explanation:
The unbalanced reaction expression is given as:
Fe + O₂ → Fe₂O₃
To balance the expression gives the coefficient of oxygen.
Assign the coefficients a,b, c and use a mathematical approach to solve this problem:
aFe + bO₂ → cFe₂O₃
Conserving Fe: a = 2c
O: 2b = 3c
Now let c = 1, a = 2, b = 
Multiply through by 2,
a = 4, b = 3 and c = 2
4Fe + 3O₂ → 2Fe₂O₃
The coefficient of O₂ is 3
Answer:
In the lab, students were encouraged to look at different types of rocks and minerals. They were also told to observe the physical properties of the rocks and minerals. Based on these physical properties, the children were able to distinguish the different types of rocks and minerals. The major differences which the children will focus on will be the color, shape, hardness, luster, streak, fracture and cleavage of the rocks and minerals.
Answer:
a) yes, it was an hydrate
b) the number of waters of hydration, x = 6
Explanation:
a) yes it was an hydrate because the mass decreased after the process of dehydration which means removal of water thus some water molecules were present in the sample.
b) NiCl2. xH2O
mass if dehydrated NiCl2 = 2.3921 grams
mass of water in the hydrated sample = mass of hydrated - mass of dehydrated = 4.3872 - 2.3921 = 1.9951 g which represent the mass of water that was present in the hydrated sample.
NiCl2.xH2O
mole of dehydrated NiCl2 = m/Mm = 2.3921/129.5994 = 0.01846 mole
mole of water = m/Mm = 1.9951/18.02 = 0.11072 mole
Divide both by the smallest number of mole (which is for NiCl2) to find the coefficient of each
for NiCl2 = 0.01846/0.01846 = 1
for H2O = 0.11072/0.01846 = 5.9976 = 6
thus the hydrated sample was NiCl2. 6H2O
Answer:
Explanation:
When adding or subtracting values, you must round your answer to the same "place" as the measurement with its last significant figure furthest to the left.
That is, you round off to the same number of decimal places as the measurement with the fewest decimal places.
The measurements of 14.0 and 10.6 have one digit after the decimal point, so you round the sum to have only one digit to the right of the decimal.
The number to be dropped (3) is less than 5, so you drop it.
