So scientist around the world can share there info without having to convert and doing extra work.
Answer:
option B is correct.
Y is a mixture in the picture.
Explanation:
Different types of substances combine physically and form a mixture.
Mixture formed by the combination of two or more substances that that combine in same physical state.
For example mixture of copper sulphate and solid chloride in dry form and that will look like white and blue crystal in a mixture.
The picture Z showing dots of same color and is not a mixture, while picture Y shows dots of different colors clearly indicating that it is picture for mixture.
Bases produce hydroxide ions, while acids produce hydrogen ions.
Bases have a pH of above 7, and are bitter and slippery.
Answer: <span>c. hydroxide ions</span>
Answer:- 12 km = 12000 m
Solution:- It's a metric unit conversion where we are asked to convert 12 km to m where km stands for kilometer and m stands for meter.
In metric conversions, kilo means 1000.
So, 1 km = 1000 m
It means, we multiply the given km by 1000 to get the answer in m as:
= 12000 m
Hence, 12 km = 12000 m.
Answer:
A. there is an isotope of lanthanum with an atomic mass of 138.9
Explanation:
By knowing the different atomic masses of both Lanthanum atoms, we can not tell anything about their occurence in nature. Therefore, all the last three options are incorrect. Because, the atomic mass does not tell anything about the availability or natural abundance of an element.
Now, the isotopes of an element are those elements, which have same number of electrons and protons as the original element, but different number of neutrons. Therefore, they have same atomic number but, different atomic weight or atomic masses.
Hence, by looking at an elements having same atomic number, but different atomic masses, we can identify them as isotopes.
Thus, the correct option is:
<u>A. there is an isotope of lanthanum with an atomic mass of 138.9.</u>
