Answer:
<h3>
Merits of modern periodic table:</h3>
- The wrong position of some elements like argon, potassium, cobalt and nickel due to atomic weights have been solved by arranging the elements in the order of increasing atomic number without changing their own places.
- The isotopes of some element have the same atomic numbers. Therefore, they find the same position in periodic table.
- It separates metals from non-metals.
- The groups of the table are divided into sub groups A and B due to their dissimilar properties which make the study of elements specific and easier.
- The representative and transition elements have been separated.
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Answer:
350 g dye
0.705 mol
2.9 × 10⁴ L
Explanation:
The lethal dose 50 (LD50) for the dye is 5000 mg dye/ 1 kg body weight. The amount of dye that would be needed to reach the LD50 of a 70 kg person is:
70 kg body weight × (5000 mg dye/ 1 kg body weight) = 3.5 × 10⁵ mg dye = 350 g dye
The molar mass of the dye is 496.42 g/mol. The moles represented by 350 g are:
350 g × (1 mol / 496.42 g) = 0.705 mol
The concentration of Red #40 dye in a sports drink is around 12 mg/L. The volume of drink required to achieve this mass of the dye is:
3.5 × 10⁵ mg × (1 L / 12 mg) = 2.9 × 10⁴ L
Answer:
Part A: 47.8 mi/h
Part B: 0.072 M/s
Part C: 0.144 M/s
Explanation:
Part A
The average speed or velocity (V) is the variation of the space divided by the variation of the time:
V = (241 - 2)/(8 -3)
V = 47.8 mi/h
Part B
As Part A, the average rate (r) of formation of I2 is the variation of the concentration divided by the variation of time:
r = (1.83 - 1.11)/(15 - 5)
r = 0.072 M/s
Part C
The rates of the substances are proportional of their number of moles (n) which are their coefficient, so:
rI2/nI2 = rHCl/nHCl
0.072/1 = rHCl/2
rHCl = 2*0.072
rHCl = 0.144 M/s
Answer:
Mercury is useful in lighting because it contributes to the bulbs' efficient operation and life expectancy. Fluorescent and other mercury-added bulbs are generally more energy efficient and last longer than incandescent and other equivalent forms of lighting.
Explanation:
It will explode together cause danger