Answer:
Capillarity , Adhesion and cohesion . The unique property of water enable life to exist . The most important property of water is movement of materials due to water , maintenance and growth and reproduction .
Explanation:
The International Bureau of Weights and Measures is the society that scientist form to bring about one universal system of measurements.
<u>Explanation:</u>
Every theoretical assumptions should be proved experimentally and for that we need a specific system to measure or quantify parameters used in those experiments or the outcome results variables.
The measurements of length should be done by measuring them in meters only and not by liters. The physical properties of every materials should have a particular way of measuring them and this is decided by the International Bureau of Weights and Measures.
They also decide the units of each measurements and the standardization of each units and weights are also done by this society.
Answer:
Thank you for da free points
Explanation:
Answer:
3.861x10⁻⁹ mol Pb⁺²
Explanation:
We can <u>define ppm as mg of Pb²⁺ per liter of water</u>.
We<u> calculate the mass of lead ion in 100 mL of water</u>:
- 100.0 mL ⇒ 100.0 / 1000 = 0.100 L
- 0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²
Now we <u>convert mass of lead to moles</u>, using its molar mass:
- 8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g
- 8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²
The nitrate reduction test identifies whether the given strain of bacteria is able to reduce nitrate to nitrite using anaerobic respiration.
In this test, the solution is incubated after adding the bacteria strain. After the incubation period is over, additional solutions Sulfuric acid (a) and Naphthylamine (b) are added to it.
If the reduction has occurred and the nitrite is present, then the solution gives red color.
If there is no color change, then the solution is tested for the presence of other reduction products like N2 gas , NH3 gas etc. This is done by adding zinc to the solution.
Zinc is able to reduce nitrate to nitrite only. Therefore a color change after the addition of zinc indicates that the bacterial strain was not able to reduce nitrate and nitrates are still present which were reduced by zinc.
If there is no color change, that means the nitrates are absent and the bacteria has reduced nitrate to some other species like N2 or NH3 gas.
Therefore , In the nitrate reduction test, only after the addition of zinc to your 24-hour incubated solutions a and b is there a color change. This indicates that the bacteria was not able to reduce nitrate to nitrite.
