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Anexo 2
Tarea 3 - Disoluciones y gases
Tablas para el desarrollo de los ejercicios. Nombre y apellidos:
Código (documento de identidad) Nombre del tutor:
Programa académico:
Ingeniería Industrial
Ejercicio 1. Leyes de los gases ideales
Tabla 1. Leyes de los gases ideales
Número
de
estudiant
e
Ley de Boyle
Ley de Charles
Ley de Gay-Lussac
5
Un gas ocupa un volumen de
V1 a una presión de P1. Si la
temperatura
permanece
constante, ¿Cuál es la presión
en mm de Hg, si se pasa a un
recipiente de 3 litros?
V
1
=1,5 L P
1
=5,50 torr
5,50
torr x
760
mmHg
1
torr
=
4180
mmHg
P
1
x V
1
= P
2
x V
2
Una llanta de un vehículo se
llena con (V1) de aire a T1.
Luego de rodar varios kilómetros
la temperatura sube a (T2)
¿Cuánto será el volumen de aire
(V2) en la llanta?
V
1 = 23 L
T
1
= 32°F
T
2
= 74°F
V
1
x T
2
= V
2
x T
1
V
2
=
V
1
xT
2
T
1
Un gas se encuentra a una
presión P
1
y una T
1
¿Cuál será la
presión si la temperatura se
incrementa a T
2
?
P
1
=1,52 atm
T
1
=35°C + 273,15 = 308,15K
T
2
= 221 K
P
1
x T
2
= P
2
x T
1
P
2
=
P
1
xT
2
T
1
Número
de
estudiant
e
Ley de Boyle
Ley de Charles
Ley de Gay-Lussac
P
2
=
P
1
xV
1
V
2
P
2
=
4180
mmHg x
1,5
L
3
L
P
2
=
2090
mmHg
(
°
F −
32) × 5
9
= °
C
T
1
= (
32
−
32) × 5
9
= 0°
C
T
1
= 273K
T
2
= (
74
−
32) × 5
9
=23,33°
C
T
2
= 23,33°
C + 273,15 T
2
= 296,48K
V
2
=
23
L x
296,48
K
273,15
K
V
2
= 25L
P
2
=
1,52
atm x
221
K
308,15
K
P
2
= 1,090 atm
Ejercicio 2: Gases ideales
Tabla 2. Gases ideales
Número
de
estudiant
e
Gases ideales
3
Una cantidad X
1
de gas ideal ocupa un volumen V
1
a una temperatura T
1 y, una presión P
1
que se
debe calcular a partir de la ecuación de gases ideales. I. ¿Cuál es la presión que se requiere para comprimir ½ volumen del gas (V
2
) contenedor a 200 °C? X
1
= 85,5 Kg
NO x 1000
g
1
K g
=
85500
g NO
85500
g NO x 1
mol NO
30
gNO
=
2850
mol NO
V
1
= 2,5 L
T
1
= 82°C + 273,15 = 355,15 K
T = 200°C + 273,15 = 473,15 K
PV = nRT
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P
1
=
nRT
V
P
1
=
2850
mol NO x
0,08205
at x L
K x mol
−
g
x
355,15
K
2,5
L
P
1
=33219,66 at
Para calcular la nueva presión P
2
del gas, debemos utilizar la ley de Boyle-Mariotte, que establece
que la presión de un gas ideal es inversamente proporcional al volumen ocupado cuando la
temperatura y la cantidad de sustancia se mantienen constantes
P
1
x V
1
= P
2
x V
2
P
2
=
P
1
xV
1
V
2
P
2
=
33219,66
at x
2,5
L
1,25
L
P
2
= 66439,32 at
II. Si se va a encerrar en un tanque de Volumen V
2
(correspondiente al punto I), el cual puede resistir
una presión manométrica máxima de 6 atm, ¿cuál sería la máxima temperatura del gas si se desea
que el tanque no estalle?
PV = nRT
Tmáx
=
PV
nR
Tmáx
=
6
atm x
1,25
L
2850
mol NO x
0,08205
at x L
Kxmolg
Tmáx = 0,032 K
Ejercicio 3: Soluciones.
Tabla 3. Soluciones
Númer
o de
estudia
nte
Datos del
ejercicio
I
II
III
5
Estudiante 3: Se
desea preparar 60
mL 0,5 N de una
solución de HCl, a
partir de un frasco
almacén del ácido
que se encuentra
al 37% y cuya
densidad es de
1,18 g/mL. I. ¿A
qué concentración
molar
se
encuentra
el
frasco almacén de
ácido? II. ¿Cuál es
Se desea preparar 60 mL
0,5 N de una solución de
HCl, a partir de un frasco
almacén del ácido que se
encuentra al 37% y cuya
densidad es de 1,18 g/mL.
I. ¿A qué concentración
molar se encuentra el
frasco almacén de ácido?
Eq g soluto = N x litro de
solución 60
mL x
1
L
1000
mL
= 0,06
¿Cuál es el porcentaje peso
a peso de la concentración
molar final?
Eq g soluto = N x litro de
solución 60
mL x
1
L
1000
mL
= 0,06 L
Eq g soluto = 0,5 N x 0,06L Eq g soluto = 0,03 III. ¿Cuál es la fracción
molar
de
soluto
presente en la solución
final?
Xmolar
=
molessoluto
molestotales
0,40
gHCl x
1
mol HCl
36,45
g
=
0,0
Xmolar
=
0,0109
mol
0,0109
moles
Xmolar
=
1
el porcentaje peso
a peso de la
concentración
molar final? III.
¿Cuál
es
la
fracción molar de
soluto presente en
la solución final?
L
Eq g soluto = 0,5 N x
0,06L Eq g soluto = 0,03 0,03
eq g HClx
36,45
g
mol
HCl
1
eq
−
g HCl
¿
1,09
g
mol
HCl
Masa HCl
=
1,09
g HClx
37%
/100 Masa HCl
=
0,40
g HCl
d
=
m
V
V
=
m
d
V
=
0,40
gHCl
1,18
g
/
mL
V
=
0,3417
mL x
1
L
1000
mL
=
0,0
0,03
eq g HClx
36,45
g
mol
HCl
1
eq
−
g HCl
¿
1,09
g
mol
HCl
%
p
p
=
masasoluto
masasolución
x
100%
d
=
m
V
m
=
d xV
m
=
1,18
g
/
mL x
0,3417
mL
m
=
0,40
g %
p
p
=
0,40
g
0,40
g
x
100%
%
p
p
=
100%
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m
=
0,40
g HClx
1
mol HCl
36,45
g
=
0
M
=
moles desoluto
litrosde solución
M
=
0,0109
mol HCl
0,000341
L
M
=
32,05
Ejercicio 4: Aplicación del tema
Tabla 4. Aplicación del tema asignado
Número de
estudiante
3
Área de campo
asignada
Zootecnia
Title
In vitro
fermentation characteristics of ruminant diets using
ethanol extract of brown propolis as a nutritional additive
Abstract The addition of levels of ethanol extract of brown propolis was evaluated by assessing
diet degradation in rumen fluid and predicting cumulative in vitro
gas production by
nonlinear (dual pool logistic and exponential) models. A total of 35 g of crude propolis
were extracted in 65 mL of cereal alcohol (95% ethanol). In a completely randomized
factorial design, the experimental diets combined four concentrations of extracted
propolis diluted in cereal alcohol (0, 50, 70, and 100% of propolis extract) and
supplementation doses (4, 8, 12, 16, and 20 mL/kg dry matter), tested in triplicate. Diet
(400 g/kg Tifton hay and 600 g/kg concentrate) was incubated for 96 h carried out three
times in three different weeks. There was significant interaction between extract
concentration and dose on the dry matter (DM) degradability. Dry matter degradability of
diet decreased exponentially as a function of the increase in dose (y = 678.55×dose
–0.271
).
Pure alcohol treatment showed a negative exponential effect, with degradability of 303.61
g/kg when administered at a dose of 20 mL/kg DM. Treatment 100% ethanol extract
reached the greatest degradability, estimated at 18.93 mL/kg DM. The treatment with
70% extract showed 6.35 mL/kg DM and the 50% extract, 7.65 mL/kg DM of minimum
degradability. The reduction potential of pure ethanol was –0.32 mL gas/mL. Estimates of
maximum gas production by dual pool logistic and exponential models were 13.10 mL
and 12.07 mL for 100% extract, respectively. The 100% extract produced the highest gas
production estimates, above 30 mL gas/100 mg DM of fermented diet. The degradation
and fermentation of ruminant diet can be improved using 13 mL/DM kg of ethanol extract
of propolis.
feed additive; gas production; propolis; ruminal degradability; ruminant nutrition
Introduction
Propolis is a natural product with antimicrobial activity (
Park et al., 2000
; Stradiotti
Júnior et al., 2004b
). The chemical composition of propolis is quite complex and
diversified because it depends on the ecology of plants visited by bees that produce it
(
Ghisalberti, 1979
). Several studies have demonstrated that the antimicrobial activity of
propolis occurs by the inhibition of bacteria classified as Gram-positive (
Ghisalberti,
1979
; Bankova et al., 2000
; Vargas et al., 2004
). However, the effects of dilution
according to the type of propolis still have to be elucidated to obtain solutions with
sufficient active principle to obtain such effects on the rumen microbiota.
According to Mirzoeva et al. (1997)
, propolis and some of its components, such as
caffeic acid phenethyl ester and quercetin, are bacteriostatic to Gram-positive and some
Gram-negative bacteria, inhibiting their motility, likely because they modify the
bionergenic status of bacterial membranes. This action is similar to that of ionophores,
which are commonly included in ruminant diet because of their conditioning role in the
ruminal environment, capable of improving the utilization of metabolic energy and
decreasing lactate levels and protein deamination (
Prado et al., 2010
).
Like ionophores, propolis has been used as an additive in ruminant nutrition to inhibit the
production of gases, particularly methane, and to decrease nitrogen losses during ruminal
fermentation (
Stradiotti Júnior et al, 2001
; Stradiotti Júnior et al., 2004a
; Ítavo et
al., 2011
; Heimbach et al., 2014
). Silva et al. (2014)
studied the effects of dietary
brown propolis on nutrient intake and digestibility in feedlot lambs compared with
monensin and concluded that the addition of brown propolis has the same effect as
monensin, with neither of them maximizing nutrient availability in diets for feedlot lambs
at seven months of age.
According to Makkar (2005)
, in vitro
gas production has been considered a suitable
method to assess the action of phytochemicals on ruminal microbial fermentation. Groot
et al. (1996)
reported that different nonlinear models with specific assumptions and
parameters are available to fit curves of cumulative in vitro
gas production, allowing
degradation parameters to be determined and increasing understanding of fermentation
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kinetics.
The present study tested the addition of different concentrations and doses of brown
propolis extract to ruminant diet and evaluated the effects of this supplementation on diet
degradation in rumen fluid, in addition to assessing the kinetics of cumulative in vitro
gas
production through exponential (
Ørskov and McDonald, 1979
) and dual pool logistic
(
Schofield et al., 1994
) nonlinear models.
Discussion Ethanol propolis extract showed contents of wax (29.90 mg/mL), dry residue (151.28
mg/mL), total phenols (27.65 mg/mL), and total flavonoids (13.98 mg/mL) above the
quality parameters established by Brazilian law (IN.3, Brasil, 2001
), which determines
minimum levels of 0.25% flavonoids (2.5 mg/mL) and 0.50% phenolic compounds (5.0
mg/mL).
Dry matter degradability decreased exponentially as a function of the increase in
doce.Thus, including increasing doses of pure ethanol in the rumen fluid has a negative
effect on microbial activity and substrate fermentation by anaerobic microorganisms in
the rumen fluid. Likewise, the negative control also decreased cumulative in vitro
gas
production, yielding 6.9 and 7.9 mL/100 mg DM according to the dual pool logistic and
exponential models, respectively.
The use of 100% extract resulted in the highest in vitro
degradability, which suggests that
components in the propolis extract promoted increasing degradation of diet DM in the
rumen fluid, likely through the selection and stimulation of certain rumen bacteria,
especially the Gram-negative variety.
The antimicrobial action of propolis on bacterial growth, membrane potential, and motility
was studied by Mirzoeva et al. (1997)
. They found that propolis affects the permeability
of the bacterial inner membrane to ions and causes dissipation of membrane potential,
hindering ATP synthesis, ion transport, and motility of Gram-positive bacteria.
The antibacterial activity of propolis against Gram-positive bacteria is strong but limited
against Gram-negative bacteria (
Bankova et al., 1999
; Marcucci et al., 2001
; Packer
and Luz, 2007
). Although the cell walls of Gram-negative bacteria are less rigid than
those of their Gram-positive counterparts, their higher resistance to propolis likely results
from the higher complexity of these structures, with liposaccharides and high lipid
content (
Vargas et al., 2004
).
The flavonoids contained in the propolis extract act against microorganisms through
inhibition of cell membrane function, bacterial activity, or synthesis of nucleic acid
(
Cushnie and Lamb, 2005
). This explains the higher degradability and cumulative gas
production of diets, added with propolis extract in relation to the negative control, which
had complete bactericidal action.
The treatment with 70 and 50% extract showed minimum degradability estimates close to
7 mL/kg DM (6.35 and 7.65 mL/kg DM, respectively). These similar estimates indicates
that even after extract dilution in 30 or 50% water, microbial fermentation and gas
production are still affected. The results suggest that the content of 13.98 mg/mL
flavonoids in the extract was probably capable of affecting fermentation in rumen fluid,
acting through bacteria selection.
The dilution of propolis ethanol extract in water reduced its bacteriostatic action, given
that it lowers the content of active compounds in the diet. Propolis flavonoids, such as
galangine, quercetin, pinocembrin, and kaempferol, are natural polyphenolic compounds
widely spread among seed plants. Propolis also contains aromatic acids and esters,
aldehydes and ketones, terpenoids and phenylpropanoids (such as caffeic and chlorogenic
acids), esteroids, amino acids, polysaccharides, hydrocarbons, fatty acids, and low
amounts of a number of compounds (
Bankova et al., 2000
; Packer and Luz,
2007
; Lustosa et al., 2008
), which are considered as total phenols (27.65 mg/mL) in
the analysis.
Park et al. (1998)
found that flavonoids are mostly extracted in ethanol solutions at 60
to 80% concentration, which inhibits microbial growth satisfactorily. They also report that
ethanol extracts at 70 to 80% show significant antioxidant activity, similar to that
observed with 100% extract in the present study , in addition to being beneficial to
ruminal diet degradability and in vitro
gas production.
Oliveira et al. (2004)
studied the effects of monensin and propolis extract on in
vitro
degradability of crude protein from different nitrogen sources using ruminal fluid
from cattle grazing Brachiaria
spp. grass. They found that both monensin and propolis
extract reduced the production of ammonia from highly degradable protein sources;
however, propolis was better because it reduced deamination (
Stradiotti Júnior et al.,
2001
), which can increase microbial activity and efficiency, given that rumen bacteria
optimize the use of dietary nitrogen sources. This corroborates with the present study, in
which in vitro
degradability was higher in diets added with propolis extract .
As estimated by both dual pool logistic and exponential models, extract concentration
and dose also affected cumulative gas production . The negative control without propolis
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(pure ethanol) decreased gas production, likely because of its bactericidal action, which
eliminated rumen fluid microorganisms.
The reduction potential estimated by the dual pool logistic model was –0.32 mL of gas per
milliliter of ethanol added. Similarly, the estimates provided by the exponential model
indicated a negative effect of the negative control using pure ethanol, with similar
reduction potential of –0.32 mL of gas per milliliter of ethanol. Alcohol acts on protein
denaturation and lipid solubilization. There may be side effects on the interference of
metabolism and eventual lysis of cells. Proteins can be denatured by extremes of pH and
by certain miscible organic solvents such as alcohol (
Nelson and Cox, 2012
).
The result of cumulative in vitro
gas production suggests that in vitro
gas production
increases with dose of propolis ethanol extract due to the higher dietary flavonoid and
total phenol content.
The maximum cumulative in vitro
gas production predicted by both models using 100%
ethanol extract of propolis were obtained with doses of 13.10 mL and 12.07 mL,
respectively. Ítavo et al. (2011)
suggested the use of brown propolis extract for 15
mL/kg DM as a substitute for sodium monensin to improve feed conversion in confined
lambs. In the present study, a positive effect was obtained using 13 mL/kg DM, which
reinforces the importance of in vitro
analysis given that the results produced may be
economically beneficial in large-scale administration. In another work, Ítavo et al
(2011)
concluded that different levels of green propolis extract in the diet of feedlot
lambs did not influence nutrient digestibility and recommended the inclusion of 7.60 mL
(2.1189 mg of dry matter and 0.1123 mg of flavonoids) of green propolis extract/day in
the diet of confined lambs to maximize efficiency,.
The findings indicate that dietary propolis improves DM degradation, likely through
bacterial selection by bacteriostatic action and cumulative gas production. However, the
dose of extract needed to improve diet degradability is limited, as shown by the quadratic
behavior of the estimates. This is probably related to the rumen environment; that is,
the in vitro
assay does not include factors such as passage rate and gradual extract
dilution, which can impair the optimal action of propolis solutions as a diet additive
because of their alcohol content.
The highest gas production estimates (above 30 mL gas/100 mg fermented DM) were
obtained with the diet with 100% ethanol extract of propolis. In a study on the addition of
residues from alcoholic extraction of brown propolis to a ruminant diet, Heimbach et al.
(2014)
reported 18.18 mL in vitro
gas production using a dose of 10 g/kg DM and
incubation in ruminal fluid of lambs. In bovine ruminal fluid, the highest gas production
they reported is 16.89 mL, obtained with diet with residue inclusion of 5 g/kg DM. The diet
tested also consisted of Tifton hay combined with corn and soybean meal-based
concentrate, but using a 50:50 roughage:concentrate ratio.
The dose of 20 mL of 70% extract exhibited average gas production of 18.26 mL/100 mg
DM, which is close to the value of 18.78 mL reported by Heimbach et al. (2014)
. The
difference in gas production estimates using 70 and 100% extracts and the results found
by those authors are likely related to the phenol and total flavonoid content in the
extracts. The propolis extraction residue tested contained 0.24 mg of total phenols and
0.35 mg of total flavonoids per gram of dry residue, whereas 100% extract exhibited
151.28 mg/mL of dry residue, 27.65 mg/mL of phenols, and 13.98 mg/mL of total
flavonoids. Given the higher phenol and flavonoid content in propolis extract compared
with its residue, the higher effect of the former on ruminal fluid bacteria is expected,
along with higher degradability and in vitro
gas production. Thus, the diets added with
100% ethanol extract of brown propolis may lead to the greatest degradability rates and
cumulative in vitro
gas production.
Conclusion
The diets added with 100% ethanol extract of brown propolis prepared with 35 g of
propolis and 65 mL of cereal alcohol promote the greatest diet degradability and
cumulative in vitro
gas production. Ethanol extract of brown propolis can be included as
nutritional additive in ruminant diets. The maximum dose of 100% propolis extract
supplementation recommended, which improves degradation and fermentation of
ruminant diets, is 13 mL/kg DM.
Reference
-
Brasil. Ministério da Saúde. Agência Nacional de Vigilância Sanitária. 2001. Legislação. Instrução Normativa n.3, de 19 de janeiro de 2001. Aprova os regulamentos técnicos de identidade e qualidade de apitoxina, cera de abelha, geléia real, pólen apícola, própolis e extrato de própolis. Brasília, DF.
-
Campos, F. P.; Bose, M. L. V.; Boin, C.; Lanna, D. P. D. and Morais, J. P. G. 2000. Avaliação do sistema de monitoramento computadorizado de digestão in vitro
Desaparecimento da matéria seca e/ou FDN pela produção de gás. Revista
Brasileira de Zootecnia 29:537-544.
-
Cushnie, T. P. and Lamb, A. J. 2005. Detection of galangin-induced cytoplasmic membrane damage in Staphylococcus aureus by measuring potassium loss. Journal of Ethnopharmacology 101:243-248.
-
Funari, C. S. and Ferro, V. O. 2006. Análise de própolis. Ciência Tecnologia
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Alimentos 26:171-178.
-
Ghisalberti, E. L. 1979. Propolis: a review. Bee World 60:59-84.
-
Goering, H. K. and Van Soest, P. J. 1970. Forage fiber analyses (apparatus, reagents, procedures, and some applications). Agriculture Handbook, 379. US Department of Agriculture, Washington, DC.
-
Referencia (Normas APA):
Brown, T., Lemay, E., Murphy, C., Bursten, B., Woodward, P. (2014). Química, la ciencia central
. (pp. 383-402, 425-
440, 513-529, 530-550). Biblioteca Virtual UNAD https://www-ebooks7-24-com.bibliotecavirtual.unad.edu.co/?
il=971
Petrucci, R., Herring, F., Madura, J., Bissonnette, C. (2017). Química general principios y aplicaciones modernas
.
(11a.
ed.).
(pp.
111-137,
465-480).
Biblioteca
Virtual
UNAD
https://www-ebooks7-24-
com.bibliotecavirtual.unad.edu.co/?il=5838
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