Answer:
Mass, m = 1.51 grams
Explanation:
It is given that,
The circumference of Aluminium cylinder, C = 13 mm = 1.3 cm
Length of the cylinder, h = 4.2 cm
We know that the density of the Aluminium is 2.7 g/cm³
Circumference, C = 2πr
Density is equal to mass per unit volume.
m is mass of the cylinder
V is the volume of the cylinder
So,
So, the mass of the cylinder is 1.51 grams.
<u>Answers:</u>
a. 131.85 grams
b. 134.69 grams
To calculate the number of grams in the number of moles given for each compound, consider the formula:
<em>Moles = No. of grams / molar mass</em>
Therefore, to find the gram it will become:
<em>No. of grams = moles x molar mass</em>
a. 0.410 mol of NaCl (sodium chloride)
Molar mass of NaCl = (286.14 + 35.45) = 321.59
No. of grams = moles x molar mass
No. of grams = 0.410 x 321.59 = 131.85 grams
b. 4.80 mol of C2H4 (ethylene)
Molar mass of C2H4 = (12.01 x 2) + (1.01 x 4) = 28.06
No. of grams = moles x molar mass
No. of grams = 4.80 x 28.06 = 134.69 grams
Answer: Positive effects: mass production of fertilizers, alkaline cleansers, refrigerant gas, dyes, explosives
Negative effects: heath problems, negative effects on soil organisms and soil organic matter, imbalances to the nitrogen cycle, high fossil fuel energy inputs, production of deadly weapons
Explanation:
The Haber process (also called Haber Bosch process) is used to produce ammonia from nitrogen and hydrogen under the high pressure. Basically, it's an artificial nitrogen fixation process. This method has both positive and negative effects on modern society.
Positive sides: ammonia is mainly used for mass production of fertilizer, which allows more food for everyone. It can be used for production of alkaline cleansers, refrigerant gas, dyes and explosives. Ammonia is also used in production of synthetic polymers, due to its role in the manufacturing of cyanide.
Negative sides: ammonia is a toxic gas, it can irritate eyes and lungs. Because of that, the excess nitrogen in soil and water coming from synthetic fertilizers can cause health problems. It is harmful for humans and animals, but it can also be harmful for plants. Environmental factors are also important. Because of the mass fixation, there is imbalance in the earth’s nitrogen cycle. Also, fossil fuels are used as a source of power for machinery in Haber's process, which increases emissions into the atmosphere. And, at least ammonia is a major component of weapons including great number of bombs.
Aluminum
Bauxite ore is the world's primary source of aluminum. The ore must first be chemically processed to produce alumina (aluminum oxide). Alumina is then smelted using an electrolysis process to produce pure aluminum metal. Bauxite is typically found in topsoil located in various tropical and subtropical regions.
An exponential decay law has the general form: A = Ao * e ^ (-kt) =>
A/Ao = e^(-kt)
Half-life time => A/Ao = 1/2, and t = 4.5 min
=> 1/2 = e^(-k*4.5) => ln(2) = 4.5k => k = ln(2) / 4.5 ≈ 0.154
Now replace the value of k, Ao = 28g and t = 7 min to find how many grams of Thalium-207 will remain:
A = Ao e ^ (-kt) = 28 g * e ^( -0.154 * 7) = 9.5 g
Answer 9.5 g.
