Answer:
mass of hydrogen collected is 0.016 gram
Explanation:
Given values:
For calculating mass we have to find the number of moles first
Ideal gas equation PV =nRT
Volume= 195 ml
Pressure: 753 torr =0.99 atm
Temperature: 25+273= 298 Kelvin
Ideal gas constant R= 0.0821 Latm/molK
Number of moles n= ?
So n= PV/RT
Adding the values
n= = (753 torr)(1 atm/760 torr)(195 mL)(1 L/1000 mL)/(0.0821 L·atm/mol·K)(273 K)
n = 0.007897 moles of H₂
Now mass of hydrogen collected = number of moles x Molar mass of H₂
= 0.007897 x 2
= 0.0157 g H₂
Now mass of hydrogen collected is 0.016 gram (rounding the amount)
Atomic mass is protons and neutrons, because they both have a mass of 1 amu. Electrons have so little mass that they can be ignored. The answer is therefore B, protons plus neutrons
<span>A.H2O = water, so it is a liquid at room temperatures (melting point = 0C) and melting point must be below 20C
B.HCl = A gas at room temperatures, so melting point (-114C) is definitely lower than 20C.
Melting points of the aqueous solution (solution in water) at different concentrations are all below that of water, i.e. 0C.
C.CH4 = A gas at room temperatures, so melting point (-182C) must be below 20C.
D.MgCl2 = A white powdery solid at room temperatures, so its melting point (714C) must be above 20C (So this is the only one among the four choices that melts above 20 ° C).</span>
Explanation:
The atoms of one element differs from the atoms of other elements in terms of the number of protons they contain. This is often taken as the atomic number of such an atom.
- The number of proton is the best indicator of the atom one is dealing with.
- Based on this number, elements are categorized into distinct columns and rows on the periodic table.
- The atomic number is the number of protons or positively charge particles in the atom.
II.
It is possible to change the identity of an atom. This is only possible by altering the atomic number of the atom.
Only nuclear reactions have this capability.
When an atom undergoes nuclear reaction that involves change in number of protons, transmutation occurs and a new atom forms.
