Ineed this asap ! what type of crystalline solid do you predict would best suit the following needs? (a) a material that can be melted and reformed at a low temperature.1)ionic solid2)molecular solid 3)metallic solid 4)covalent network solid(b) a material that can be drawn into long, thin wires. 1)ionic solid 2)molecular solid 3)metallic solid 4)covalent network solid(c) a material that conducts electricity when molten.1)ionic solid 2)molecular solid 3)metallic solid 4)covalent network solid (d) an extremely hard material that is non-conductive.1)ionic solid 2)molecular solid 3)metallic solid 4)covalent network solid

A- molecular solid

B-metallic solid

C-ionic solid

D-covalent network solid

Explanation:

A molecular solid is held together by weak vanderwaals forces. It can be melted easily but reformed at low temperature when the kinetic energy of molecules is sufficiently reduced. An ionic solid is a network of oppositely charged ions linked together into a three dimensional rigid network. The ions are immobile hence it cannot conduct electricity in the solid state. When the solid melts, the ions become free hence it can now conduct electricity. Metals can be drawn into wire (ductility), this is a fundamental property of metals. Covalent network solid are hard and often have no free valence electrons e.g diamond. They do not conduct electricity

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

a polar bond is formed when electrons are shared unevenly between atoms