<h3>
Answer:</h3>
Lead-205 (Pb-205)
<h3>
Explanation:</h3>
<u>We are given;</u>
We are supposed to identify its product after an alpha decay;
- Polonium-209 has a mass number of 209 and an atomic number of 84.
- When an element undergoes an alpha decay, the mass number decreases by 4 while the atomic number decreases by 2.
- Therefore, when Po-209 undergoes alpha decay it results to the formation of a product with a mass number of 205 and atomic number of 82.
- The product from this decay is Pb-205, because Pb-205 has a mass number of 205 and atomic number 82.
- The equation for the decay is;
²⁰⁹₈₄Po → ²⁰⁵₈₂Pb + ⁴₂He
- Note; An alpha particle is represented by a helium nucleus, ⁴₂He.
0.125 g=(0.125 g)(1000 mg/1g)=125 mg.
Then, we need 125 mg of ampicillin.
5 ml of liquid suspension contains 250 mg of ampicilling , therefore:
5 ml----------------250 mg of ampicilling
x--------------------125 mg of ampicilling
x=(5 ml * 125 mg of ampicilling) / 250 mg of ampicilling=2.5 ml
Answer: we require 2.5 ml
Answer:
The sun shines with equal intensity on a farm field, an asphalt road and the ocean. So basically asphalt road are heated the most during the day
Explanation:
The heat of water is more than the specific heat of sand.
Therefore sand is hot.
.Water is reflecting solar radiation.
The land retains more heat since the land absorb solar radiation.
Therefore the land surfaces warm faster.
Since water is a slow conductor of heat, it need more energy than the sand. so its temperature is increasing. soil loses heat faster.
The ocean heats slower than land , the land air is more warmer than lean air. After the sun set the land loses heat quickly .The air above it cools.
Vitamin K and potassium are essential micronutrients the body needs to develop and function properly. The two share some things in common, but they’re not the same.
Each has a unique set of properties and purposes. Unlike vitamin K, potassium is not a vitamin. Rather, it’s a mineral.
On the periodic table, the chemical symbol for potassium is the letter K. Thus, people sometimes confuse potassium with vitamin K.
This article highlights some of the main similarities and differences between vitamin K and potassium.
Answer:
3) NaCl.
Explanation:
<em>∵ ΔTf = iKf.m</em>
where, <em>i</em> is the van 't Hoff factor.
<em>Kf </em>is the molal depression freezing constant.
<em>m</em> is the molality of the solute.
<em>The van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass. </em>
<em></em>
- For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1.
<em>So, for sugar: i = 1.</em>
<em>∴ ΔTf for sugar = iKf.m = (1)(Kf)(2.0 m) = 2 Kf.</em>
<em></em>
- For most ionic compounds dissolved in water, the van 't Hoff factor is equal to the number of discrete ions in a formula unit of the substance.
For NaCl, it is electrolyte compound which dissociates to Na⁺ and Cl⁻.
<em>So, i for NaCl = 2.</em>
<em>∴ ΔTf for NaCl = iKf.m = (2)(Kf)(1.0 m) = 2 Kf.</em>
<em></em>
<em>So, the right choice is: 3) NaCl.</em>
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