The electrons are what determines the energy level and reaction of the valence shell, hope it helps ❤️✌️
Answer:

Explanation:
= Mass of water = 100 g
= Specific heat of water = 
= Mass of copper = 20 g
= Specific heat of copper = 
= Temperature change in water = 
= Temperature change in cooper = 
T = Final temperature of the system
The heat balance of the system is given by

The final temperature of the water is
.
Answer:
8.8g of Al are necessaries
Explanation:
Based on the reaction, 2 moles of Al are required to produce 3 moles of hydrogen gas.
To solve this question we must find the moles of H2 in 11L at STP using PV = nRT. With these moles we can find the moles of Al required and its mass as follows:
<em>Moles H2:</em>
PV = nRT; PV/RT = n
<em>Where P is pressure = 1atm at STP; V is volume = 11L; R is gas constant = 0.082atmL/molK and T is absolute temperature = 273.15K at STP</em>
Replacing:
1atm*11L/0.082atmL/molK*273.15K = n
n = 0.491 moles of H2 must be produced
<em />
<em>Moles Al:</em>
0.491 moles of H2 * (2mol Al / 3mol H2) = 0.327moles of Al are required
<em />
<em>Mass Al -Molar mass: 26.98g/mol-:</em>
0.327moles of Al * (26.98g / mol) = 8.8g of Al are necessaries
Wind becuase you can feel it whhich is physical
A is correct. If an atom has more protons than electrons it is positively charged, if more electrons than protons it is negatively charged. An equal number of each will make it neutral