Apiece of dry ice (solid carbon dioxide) with a mass of 5.50 g is placed in a 10.0-l vessel that already contains air at 705 torr and 24 °c. after the carbon dioxide has totally sublimed, what is the partial pressure of the resultant co2 gas, and the total pressure in the container at 24 °c?

 The partial  pressure  of  resultant CO₂  gas  is 231.5 torr

The total  pressure = 936.5 torr

 calculation

The partial  for CO₂  is calculated using  the ideal gas equation

That is PV=nRT

where;

p(pressure = ?

V( volume) = 10.0 l

n(number of moles) = mass÷molar mass

from periodic table the molar mass of CO₂ = 12 + (16 x2)  = 44 g/mol

moles = 5.50 g÷44 g/mol =0.125 moles

R( gas constant) = 62.36 torr

T ( temperature) = 24°c into Kelvin = 24 +273 =297 K

make P the subject  of the formula by diving both side of equation by V

P  =nRT/V

P  ={( 0.125 moles x 62.36 L.torr/Mol.K  x297 K)  / 10 L}  = 231.5 torr

Total pressure = partial pressure for air + partial  pressure for CO₂

= 705 torr + 231.5 torr =936.5 torr

part 1: the half-life of the element is 22 years.

part 2: it will take 132.02 year for the sample to decay from 308.0 g to 4.8125 g.

explanation:

part 1: there are two ways to determine the half life time.

first way: the half life time can be determined directly from its definition as it is the time required for the sample to decay to its half concentration.

from the data the initial concentration was 45.0 g and decayed to its half value (22.5 g) in 22.0 years.

second way: the radio active decay is considered first order reaction so we can use the laws of first order reactions.

k = (1/t) ln (a/a-x), where k is the rate constant of the reaction,

t is the time of the reaction

a is the initial concentration of the reactant

a-x is the remaining concentration at time (t)

a = 45.0 g the initial concentration at t = 0 year.

at t = 22 year, a-x = 22.5 g

then k = (1/22 year) ln (45.0 g/ 22.5 g) = 0.0315 year-1.

the half-life time (t1/2) = ln 2/ k = 0.693/ k =0.693/ 0.0315 = 22 years.

part 2:

using the same law k = (1/t) ln (a/a-x),

using the given data; a = 308.0 g and a-x = 4.8125 g and the calculated k from the part 1 (k = 0.0315 year-1)

t = (1/k) ln (a/a-x) = (1/0.0315) ln (308.0/ 4.8125) = 132.02 years

b) mutualism

hope this : )