T = final temperature of the block
T₀ = initial temperature of the block = 23.4 °C
Q = energy lost from the wooden block = - 759 J
c = specific heat capacity of wood = 1.716 J/(g °C)
m = mass of the wooden block = 27.2 g
Heat lost from the block is given as
Q = m c (T - T₀)
inserting the values
- 759 = (27.2) (1.716) (T - 23.4)
T = 7.1 °C
A pure substance, only one type of atom
Answer:199mL
Explanation:
Let V ml be the volume of blood in animal.
When 1.0 ml sample is added, total volume becomes V+1.0ml. Its activity is 1000 dpm.
After equilibrium, 2.0 ml of the sample had activity of 10 dpm.
Hence, after equilibrium, the activity of V+1.0 ml of blood sample will be 10/2 (V+1.0ml)=1000dpm
Hence, V=199ml.
Answer:
a) +640 kJ/mol or +1.06x10⁻¹⁸ J
b) +276 kJ/mol
Explanation:
To dissociate the molecule, the bond must be broken, thus, it's necessary energy equal to the energy of the bond, which can be calculated by:
E = (Q1*Q2)/(4*π*ε*r)
Where Q is the charge of the ions, ε is a constant (8.854x10⁻¹²C²J ⁻¹ m⁻¹), and r is the bond length. Each one of the ions has a charge equal to 1. The elementary charge is 1.602x10⁻¹⁹C, which will be the charge of them.
1 mol has 6.022x10²³ molecules (Avogadros' number), so the energy of 1 mol is the energy of 1 molecule multiplied by it:
E = 6.022x10²³ *(1.602x10⁻¹⁹)²/(4π*8.854x10⁻¹²*2.17x10⁻¹⁰)
E = +640113 J/mol
E = +640 kJ/mol
Or at 1 molecule: E =640/6.022x10²³ = +1.06x10⁻²¹ kJ = +1.06x10⁻¹⁸ J
b) The energy variation to dissociate the molecule at its neutral atoms is the energy of dissociation less the difference of the ionization energy of K and the electron affinity of F (EA):
498 = 640 - (418 - EA)
640 -418 + EA = 498
222 + EA = 498
EA = +276 kJ/mol
<h3><u>Answer:-</u></h3>
3. <u>Proton</u> is the subatomic particle which accounts for most of an atom's mass.
4. <u>Electrons</u> are the subatomic particle which accounts for most of atoms volume.
