Answer:
Number of moles = 1.97 mol
Explanation:
Given data;
Number of moles of I₂ = ?
Mass = 500.0 g
Solution:
Number of moles = mass/ molar mass
Molar mass of I₂ = 253.8 g/mol
Number of moles = 500 g / 253.8 g/mol
Number of moles = 1.97 mol
Answer:
0.017 mole of Pb(NO₃)₂.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2KOH + Pb(NO₃)₂ —> 2KNO₃ + Pb(OH)₂
From the balanced equation above,
1 mole of Pb(NO₃)₂ reacted to produce 2 moles of KNO₃.
Finally, we shall determine the number of mole of Pb(NO₃)₂ required to produce 0.034 mole of KNO₃. This can be obtained as follow:
From the balanced equation above,
1 mole of Pb(NO₃)₂ reacted to produce 2 moles of KNO₃.
Therefore, Xmol of Pb(NO₃)₂ will react to produce 0.034 mole of KNO₃ i.e
Xmol of Pb(NO₃)₂ = 0.034 / 2
Xmol of Pb(NO₃)₂ = 0.017 mole.
Thus, 0.017 mole of Pb(NO₃)₂ is needed for the reaction.
Answer:
The human eye can only see white visible light and it contains all the colors of the rainbow, from red to violet.
Explanation:
But visable light comes in many "colors" such as radio, infrared, ultraviolet, X-ray, and gamma-ray that are invisible to the naked eye.The reason that the human eye can see the spectrum is because those specific wavelengths stimulate the retina in the human eye.
Answer:
False
Explanation:
A significant number is a number that is used to express the accuracy in a measurement. There are some rules that binds the identification of significant figures when reporting a scientific measurement.
- All non-zero numbers are significant
- Zeros in between two digits are significant.
- Zeros to the right of the decimal are significant.
- Leading zeros are just place holders and are not significant.
- Trailing zero in a whole number with decimal is significant
- Trailing zero without a decimal is not significant.
source: http://ccnmtl.columbia.edu/projects/mmt/frontiers/web/chapter_5/6665.html
We can see that not all zeros in a measurement is significant. For example, 540 has 2 significant numbers because the zero is not significant but 540.2 has 4 significant numbers.
