Answer:
About 60.
Explanation:
Mendeleev knew of 63 elements. He wrote their properties on cards and arranged them in order of atomic mass.
That's how he discovered that the properties of elements are periodic functions of their atomic masses.
Answer:
D. 4.75 m/s west
Explanation:
You can immediately get the answer once you know the formula for<em> velocity.</em>
- The formula for velocity is: Velocity (V) =

The distance is 95 meters while the time is 20 seconds. All you have to do is to divide <u>95 meters by 20 seconds</u>.
Let's solve:
- V =

- V =

- V = 4.75 meters per second
Since Brenda is going west with her her skateboard, then you have to add <em>west </em>as her direction.
Brenda's velocity is 4.75 m/s west.
Answer:
There will be one Al3+ ion.
There will be 3 NO3- ions
Explanation:
Dissociation equation:
Al(NO₃)₃ → Al³⁺ + 3NO₃¹⁻
When aluminium nitrate dissociate it produces one silver ion (Al³⁺) and three (NO₃¹⁻) ions.
Properties of Al(NO₃)₃:
It is inorganic compound having molecular mass 169.87 g/mol.
It is white odor less compound.
Its density is 4.35 g/mL.
Its melting and boiling points are 120°C and 440°C.
It is soluble in water.
It is sued to treat infections.
It is used in the photographic films.
It s toxic and must be handled with great care.
Answer:
H2
Explanation:
Critical temperature is the temperature above which gas cannot be liquefied, regardless of the pressure applied.
Critical temperature directly depends on the force of attraction between atoms, it means stronger the force of higher will be the critical temperature. So, from the given options H2 should have the highest critical temperature because of high attractive forces due to H bonding.
Hence, the correct option is H2.