Answer:
- 0.674 kJ.
Explanation:
The equation used to solve this problem is:
Q = mCΔT
where,
Q = amount of heat
m = mass of the substance
C = specific heat capacity
ΔT = change in temperature
= Temp.f - Temp.i
Given:
m = 29.2 g
Temp.i = 79°C
Temp.f = 27°C
Cp(iron) = 0.444 J/g.K
Q = mCΔT
ΔT = 27.0°C - 79.0°C
= -52°C
= 29.2 * 0.444 * -52
Q = - 674.17 J
= 0.674 kJ.
pH=6.98
Explanation:
This is a very interesting question because it tests your understanding of what it means to have a dynamic equilibrium going on in solution.
As you know, pure water undergoes self-ionization to form hydronium ions, H3O+, and hydroxide anions, OH−.
2H2O(l]⇌H3O+(aq]+OH−(aq]→ very important!
At room temperature, the value of water's ionization constant, KW, is equal to 10−14. This means that you have
KW=[H3O+]⋅[OH−]=10−14
Since the concentrations of hydronium and hydroxide ions are equal for pure water, you will have
[H3O+]=√10−14=10−7M
The pH of pure water will thus be
pH=−log([H3O+])
pH=−log(10−7)=7
Now, let's assume that you're working with a 1.0-L solution of pure water and you add some 10
For a neutral atom, the number of positive protons is equal to the number of negative electrons and the charge is zero.
For this question, we see that the number of protons exceeds the number of electrons by 2, which means that this ion in a positively charged charged ion with charge of +2.
Answer:
1 g of Carbon
Explanation:
This is because because carbon has lower molar mass than thorium or copper so a 1-g sample of carbon contains more atoms than 1 g of cobalt or lead.
