We can define atomic mass the total of number of protons and number of neutrons in an atom or isotope.
<span>So when an isotope of yttrium has 39 protons and 59 neutrons, its atomic mass is equal to;
number of protons + number of neutrons = 39 + 59 = 98</span>
Answer:
(d) soap.
Explanation:
A soap is obtained by alkaline hydrolysis of a fat to yield the soap and glycerol. This process is known as saponification.
A soap solution is usually basic. Since phenolphthalein turns pink in an alkaline solution, then when phenolphthalein is added to a soap solution, the solution soon turns pink because it is alkaline in nature.
As a matter of fact, a soap sometimes has almost the pH of baking soda!
The correct matches are:
1. Exosphere - Temperatures reach as high as 2000 C yet it feels very cold
This is the top layer of the atmosphere. The atoms are so dispersed that despite it having very high temperature it doesn't feel like it at all.
2. Thermosphere - Particles that have enough energy can escape into space
The thermosphere is the fourth highest layer of the atmosphere. The atoms in this layer are relatively distant from one another, so the particles that have enough energy manage to escape easily into the exosphere and then the space.
3. Mesosphere - It is the coldest region of the atmosphere
The mesosphere is the third highest layer. In this layer the temperatures constantly drop, and they go down to -85 degrees, making it the coldest layer by far.
4. Stratosphere - Ninety percent ozone is in this layer
The startosphere has a separte zone in it which is dominated by only one gas, the ozone. It is called the ozone layer, the one that protects the Earth from too intense UV radiation, and in fact over 90% of this gas is locate here.
5. Troposphere - It is warm due to the heat from Earth's surface
The troposphere is the densest and lowest of the layers. It is the one that also has Greenhouse gases which manage to trap the heat that is radiated from the surface of the Earth, thus keeping this layer relatively warm.
Answer is: chemical.
If the arrangement of particles is changed, that is chemical change or chemical reaction (new substance is formed).
In physical change, the bonds between oxygen and hydrogen can not be separated.
For example, balanced chemical reaction: 2Mg(s) + O₂(g) → 2MgO(s).
Chemical changes (chemical synthesis) is when a substance combines with another (in this example magnesium and oxygen) to form a new substance.
Answer: The answer is D, Coal
hope this helps.
