The following ions contain the same number of electrons. Rank them in order of decreasing ionic radii. Rank from largest to smallest radius. To rank items as equivalent, overlap them. se3+ cl-

Cl- < Se3+ is the decreasing order of ionic radii of the two ions.

Explanation:

Atomic number of Se= 34 Se3+ will have 31 electrons (+ sign indicates loss of electron)

Atomic number of chlorine is 17, Cl- will have 18 electrons (- sign shows gain of electrons)

Number of electrons in their valence shell:

Se3+ = 2,8,18,3

Cl- = 2,8,8

The Se3+ atoms have K.L.M.N shells while Cl- K,L,M shells

The size of the ions is based on the effective nuclear charge on the ion. The loss in electron causes small cation and gain in electron causes increase in anion size.

The number of occupied shells more the number more is the ionic radii.

Se3+ will have large ionic radii as Se+ has four filled shells.

Cl- < Se3+ (decreasing order of ionic radii)

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

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds