Answer:
Mass = 4.6 g
Explanation:
Given data:
Number of molecules of sucrose = 8.1 ×10²¹ molecules
Mass of sucrose = ?
Solution:
First of all we will calculate the number of moles by using Avogadro number.
1 mole × 8.1 ×10²¹ molecules / 6.022×10²³ molecules
1.35 × 10⁻² mol
Mass of sucrose:
Mass = number of moles × molar mass
Molar mass = 342.3 g/mol
Mass = 1.35 × 10⁻² mol ×342.3 g/mol
Mass = 462.1 × 10⁻² g
Mass = 4.6 g
Answer:
3. 3.45×10¯¹⁸ J.
4. 1.25×10¹⁵ Hz.
Explanation:
3. Determination of the energy of the photon.
Frequency (v) = 5.2×10¹⁵ Hz
Planck's constant (h) = 6.626×10¯³⁴ Js
Energy (E) =?
The energy of the photon can be obtained by using the following formula:
E = hv
E = 6.626×10¯³⁴ × 5.2×10¹⁵
E = 3.45×10¯¹⁸ J
Thus, the energy of the photon is 3.45×10¯¹⁸ J
4. Determination of the frequency of the radiation.
Wavelength (λ) = 2.4×10¯⁵ cm
Velocity (c) = 3×10⁸ m/s
Frequency (v) =?
Next, we shall convert 2.4×10¯⁵ cm to metre (m). This can be obtained as follow:
100 cm = 1 m
Therefore,
2.4×10¯⁵ cm = 2.4×10¯⁵ cm × 1 m /100 cm
2.4×10¯⁵ cm = 2.4×10¯⁷ m
Thus, 2.4×10¯⁵ cm is equivalent to 2.4×10¯⁷ m
Finally, we shall determine the frequency of the radiation by using the following formula as illustrated below:
Wavelength (λ) = 2.4×10¯⁷ m
Velocity (c) = 3×10⁸ m/s
Frequency (v) =?
v = c / λ
v = 3×10⁸ / 2.4×10¯⁷
v = 1.25×10¹⁵ Hz
Thus, the frequency of the radiation is 1.25×10¹⁵ Hz.
Answer:
Según el científico inglés John Dalton, los átomos son esferas elásticas e indivisibles. Así, según él, el átomo es el bloque de construcción más pequeño de la materia. Es homogéneo e indivisible, y todos los átomos de un elemento químico dado son idénticos (es decir, tienen el mismo conjunto de propiedades).
Aunque se descubrió a finales del siglo XIX que los átomos están hechos de partículas aún más pequeñas y pueden sufrir transformaciones, y que los átomos de un elemento dado pueden diferir ligeramente entre sí (isótopos), la teoría de Dalton fue la base para el desarrollo de la tecnología química moderna.
This means a release of free energy from the system corresponds to a negative change in free energy, but to a positive change for the surroundings.
Answer:
For part (a): pHsol=2.22
Explanation:
I will show you how to solve part (a), so that you can use this example to solve part (b) on your own.
So, you're dealing with formic acid, HCOOH, a weak acid that does not dissociate completely in aqueous solution. This means that an equilibrium will be established between the unionized and ionized forms of the acid.
You can use an ICE table and the initial concentration ofthe acid to determine the concentrations of the conjugate base and of the hydronium ions tha are produced when the acid ionizes
HCOOH(aq]+H2O(l]⇌ HCOO−(aq] + H3O+(aq]
I 0.20 0 0
C (−x) (+x) (+x)
E (0.20−x) x x
You need to use the acid's pKa to determine its acid dissociation constant, Ka, which is equal to
