The half-life of Th-232 is 1.405 × 10¹⁰ years
Time elapsed = 2.8 x 10⁹ years
Equation of radioactive decay:
A = A₀ = (1/2)^ t/t₁/₂
where A₀ is the initial amount, A is the amount after time t, t₁/₂ is the half file
The fraction of thorium-232 that remains in the rock after 2.8 billions years is,
A/A₀ = (1/2) ^ (2.8 x 10⁹/ 1.405 × 10¹⁰) = 0.871
Therefore, the percentage of thorium-232 in the rock that was dated at 2.8 billions year = 87.1%
Answer:
fungi
Explanation:
because they are heterotrophs
Answer:
The amount of heat required to raise the temperature of a 32g sample of water from 8°C to 22°C is 1,874.432 J
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
Sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).
Between heat and temperature there is a direct proportional relationship. The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat and the mass of the body. So, the equation that allows to calculate heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature.
In this case:
- c= 4.184

- m= 32 g
- ΔT= Tfinal - Tinitial= 22°C - 8°C= 14°C
Replacing:
Q= 32 g* 4.184
*14 °C
Solving:
Q= 1,874.432 J
<u><em>The amount of heat required to raise the temperature of a 32g sample of water from 8°C to 22°C is 1,874.432 J</em></u>
I believe the mass of the product will be 400 grams. This is because according to the law of conservation of mass, mass is neither created nor destroyed . In a closed system, the mass of reactants is equal to mass of products. Therefore, since the total mass of the reactants is 400 grams then the mass of the products will still be 400 grams
Answer:
0°C and 1 atm
Explanation:
This are the conditions of temperature and pressure defined by IUPAC as standard.
But also, the definition used by the NIST considerates a temrperature of 20°C and a pressure of 1 atm