Answer:
Demisty = mass/volume = 142/ (2×2×4) = 142 / 16 =
8.875g/cm^3
Explanation:
Answer:
Mass = 18.9 g
Explanation:
Given data:
Mass of Al₂O₃ formed = ?
Mass of Al = 10.0 g
Solution:
Chemical equation:
4Al + 3O₂ → 2Al₂O₃
Number of moles of Al:
Number of moles = mass/molar mass
Number of moles = 10.0 g/ 27 g/mol
Number of moles = 0.37 mol
Now we will compare the moles of Al and Al₂O₃.
Al : Al₂O₃
4 : 2
0.37 : 2/4×0.37 = 0.185 mol
Mass of Al₂O₃:
Mass = number of moles × molar mass
Mass = 0.185 mol × 101.9 g/mol
Mass = 18.9 g
Answer:
No, in science their meanings are not the same as their everyday meanings.
Explanation:
In Science, Precision and Accuracy are defined as,
Accuracy:
Accuracy is the value which is closest to the known or standard value.
Precision:
While, Precision is the value of closeness of two measured values to each other.
Example:
Let suppose in Chemistry Lab you weight an object as 50 g. While the actual weight of that object is 30 g. It means your reading is not accurate.
On second measurement you find that the object weight is 31 g. This time your reading is not precise.
<span>The first method to determine the chemical composition of a substance in space was using light. By determining red shift in the observed spectrum of light they could determine the elements they were observing. Different elements change the way light behaves and from this scientists can determine the makeup of things such as stars and nebulas.</span>
