Answer:

Explanation:
Hello.
In this case, taking into account that HCl has one molecule of hydrogen per mole of compound which weights 36.45 g/mol, we compute the number of molecules of hydrogen in hydrochloric acid by considering the given mass and the Avogadro's number:

Now, from the 180 g of water, we see two hydrogen molecules per molecule of water, thus, by also using the Avogadro's number we compute the molecules of hydrogen in water:

Thus, the total number of molecules turns out:

Regards.
Answer:
Luster of aluminum is Silver-White.
Explanation:
Aluminium is a Silver-White metal which is extracted from the Bauxite ore which can be reddish brown, white, tan, grey-white and tan-yellow in color and have the minerals like Gibbsite, Boehmite and Diaspore which are the minerals of the aluminium.
The Bauxite is the rock from which the Bauxite ore is extracted which have the minerals of the aluminum.
The luster of a metal is the color and shine of it and its shiny appearance.
Aluminium is a light weight metal but have a moderate hardness which makes a wider use of it. Aluminium is used in many places where the weight of the material is kept light but its hardness can be increased by mixing some other metals in it making hard alloy with lighter weight.
It is used in transportation vehicles, buildings, and many other places like Air crafts as the weight should be kept controlled to give a perfect lift to the Air craft.
Specificity. It’s really loose to say that something is fast, since speed can be scalarly linked and relative. I could say that both a car on the highway is fast, but so is the speed of light. The actual speed of something helps to do away with the arbitrary nature of using “fast” and “slow”; however, we’re still at step one of the person who is receiving the information is unfamiliar with the scale that the actual speed is defined in.
Answer:
The frequency is 
Explanation:
From the question we are told that
The energy required to ionize boron is 
Generally the ionization energy of boron pre atom is mathematically represented as

Here
is the Avogadro's constant with value 
So

=> 
Generally the energy required to liberate one electron from an atom is equivalent to the ionization energy per atom and this mathematically represented as

=> 
Here h is the Planks constant with value 
So

=> 
Answer:
I remember doing this in 7th,
1. D
2. B or D, more leaning on B though
3. A