When elements bond to form compounds, what may change

Explanation:

Elements bond to each other by either (loosing / gaining) or sharing electrons with each other .

When bond is formed by loosing or gaining electron between metals and nonmetals then that type of bond is called ionic bond or electrovalent bond. Examples :-Nacl, Kcl etc..

When bond is formed between two elements that are non metals and bond form in between is due to sharing of electrons equally is called covalent bond.ex- Ccl4 , Sicl4 etc.

When bond formed between elements are shared unequally between atoms of elements then it is called co-ordinate bond. Ex:- No2, HCl etc..

Some people think about Metallic bond it's pretty simple actually it takes between same metal lattice. Definition is as follows

A metallic bonding is defined as where electrons freely move around a metal lattice (the metal atoms close united) to form a bond between the entire metallic element.ex:-Na, Mg and all other S , d and f block elements .

Last but not the least , Take case of hydrogen bonding it takes Place between H and electronegative elements like ( o , F , Cl , N ) etc examples are Hf , HCl , h2O etc.

Hope you have got the idea.

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.