A chemical property is a characteristic observed during a reaction where the substance's chemical composition changes. In the provided options, 'Platinum does not react with oxygen at room temperature' and 'The copper sheets of the Statue of Liberty have acquired a greenish coating over the years' are chemical properties.
In Chemistry, a chemical property is a characteristic that is observed during a reaction in which the chemical composition or identity of the substance is changed. Taking a look at the options provided:
So, the correct answers are options B and D. Both entail a change or lack of change in the chemical identity of a substance.
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2) the volume of 0.150 M KMnO4 needed to replaced 1.85 mol MnCl2
B. 0.0860
C. 0.113
D. 0.761
The dry solute has a mass of 0.086 g. 0.113 g of water evaporated while heating, the concentration in G solute / mL solvent at 30.1 C is 0.88.
To find the concentration in g solute / mL solvent, we first need to find the mass of the solvent left after evaporation:
Mass of water before evaporation = 0.113 g
Mass of water after evaporation = 0.113 g - 0.086 g = 0.027 g
Since 1 g of water has a volume of 1 mL, the volume of water after evaporation is also 0.027 mL.
Next, we need to convert the temperature to Kelvin:
T = 30.1 + 273.15 = 303.25 K
We can now use the formula:
concentration = (mass of solute / mass of solvent) / (1 - (mass of water evaporated / mass of solvent))
Plugging in the values we get:
concentration = (0.086 g / (0.027 g)) / (1 - (0.113 g / (0.086 g + 0.027 g)))
concentration = 0.88 g/mL
Therefore, the answer is A. 0.88.
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Answer:
A
Explanation:
worked for me on acellus
compound with a molecular mass of 46.07 amu causesthe temperature
in the calorimeter to rise from 25.000oC to 30.589
oC. The total heat capacity ofthe calorimeter and all
its contents is 3576 JoC-1. What is
the energy of combustion ofthe organic compound,
DU/ kJ
mol-1?
Answer:
1383.34 kJ/mol is the energy released on combustion of the organic compound.
Explanation:
Mass of an organic compound = 0.6654 g
Molar mass of organic compound = 46.07 g/mol
Moles of an organic compound =
Let heat evolved during burning of 0.6654 grams of an organic compound be -Q.
Heat absorbed by calorimeter = Q' = -Q
The total heat capacity of the calorimeter all its contents = C
C = 3576 J/°C
Change in temperature of the calorimeter =
ΔT = 30.589°C - 25.000°C = 5.589°C
Q' = 19.975 kJ
Q = -19.975 kJ (negative sign; energy released)
0.01444 moles of an organic compound gives 19.975 kilo Joule.
The 1 mole of an organic compound will give :
Pb(NO₃)₂ ⇒limiting reactant
moles PbI₂ = 1.36 x 10⁻³
% yield = 87.72%
Given
Reaction(unbalanced)
Pb(NO₃)₂(s) + NaI(aq) → PbI₂(s) + NaNO₃(aq)
Required
Solution
Balanced equation :
Pb(NO₃)₂(s) + 2NaI(aq) → PbI₂(s) + 2NaNO₃(aq)
mol Pb(NO₃)₂ :
= 0.45 : 331 g/mol
= 1.36 x 10⁻³
mol NaI :
= 250 ml x 0.25 M
= 0.0625
Limiting reactant (mol : coefficient)
Pb(NO₃)₂ : 1.36 x 10⁻³ : 1 = 1.36 x 10⁻³
NaI : 0.0625 : 2 = 0.03125
Pb(NO₃)₂ ⇒limiting reactant(smaller ratio)
moles PbI₂ = moles Pb(NO₃)₂ = 1.36 x 10⁻³(mol ratio 1 : 1)
Mass of PbI₂ :
= mol x MW
= 1.36 x 10⁻³ x 461,01 g/mol
= 0.627 g
% yield = 0.55/0.627 x 100% = 87.72%
b} The exact time when an individual atom will decay can be accurately predicted.
c} After each half-life, the amount of radioactive material is reduced by half.
d) All radioactive isotopes have the same half-life.
e} The decay of individual atoms in a sample of radioactive material is random.
Answer: b} The exact time when an individual atom will decay can be accurately predicted.
c} After each half-life, the amount of radioactive material is reduced by half.
Explanation:
All radioactive decay follows first order kinetics.
Rate law expression for first order kinetics is given by:
where,
k = rate constant
t = time taken for decay process
a = initial amount of the reactant
a - x = amount left after decay process
Expression for calculating half life, which is the time taken by the half of the reactants to decompose is:
Answer:
For plato, the answer is C: after each half tile, the amount of radioactive material is reduced by half
Please help?????
Explanation:
4.92*10-3=4.92/10^3=
4.92/1000=0.00492