Answer:
1
The reaction is exothermic
2
[tex]H = -1.1 \ KJ[/tex]
3
[tex]\Delta H_{rxn} = -6.24 \ KJ/ mol[/tex]
Explanation:
From the question we are told that
The mass of the sodium chloride is (NaCl ) is [tex]m_s = 10.3 \ g[/tex]
The mass of water is [tex]m_w = 250 \ g[/tex]
The initial temperature is [tex]T_i = 23^oC[/tex]
The temperature after 3 minutes is [tex]T_3 = 22.2 ^oC[/tex]
The time taken for temperature to fall is t = 3 minutes
The reaction is
[tex]NaCl_{ (s)} \rightarrow Na^+ _{(aq)} + Cl^-_{ (aq)}[/tex]
The reaction is exothermic because the temperature fell
Generally the mass of the solution is mathematically represented as
[tex]M = m_w + m_s[/tex]
=> [tex]M = 250 + 10.3 [/tex]
=> [tex]M = 260.3 \ g [/tex]
Gnerally the heat energy released from the solution is mathematically represented as
[tex]H = M * C_s * (T_3 - T_i)[/tex]
Here [tex]C_s[/tex] is the specific heat of solution which for this question we would assume it is the specific heat of water which has a value of
[tex]Cs = C_w = 4.18 J/g^oC[/tex]
So
[tex]H = 260.3 * 4.18 * (22- 23)[/tex]
[tex]H = -1088.054 \ J[/tex]
[tex]H = -1.088054 \ KJ[/tex]
[tex]H = -1.1 \ KJ[/tex]
Generally the number of moles of NaCl is mathematically represented as
[tex]nNaCl = \frac{m_s}{zNaCl}[/tex]
Here [tex]zNaCl[/tex] is the molar mass of NaCl and the value is
[tex]zNaCl = 58.44 \ g/mol[/tex]
So
[tex]nNaCl = \frac{10.3}{58.44 }[/tex]
=> [tex]nNaCl = 0.1762 \ moles[/tex]
Generally reaction enthalpy is mathematically represented as
[tex]\Delta H_{rxn} = \frac{H}{nNaCl}[/tex]
[tex]\Delta H_{rxn} = \frac{-1.1}{0.1762 }[/tex]
[tex]\Delta H_{rxn} = -6.24 \ KJ/ mol[/tex]
In a certain chemical reaction, 2 solid Mg atoms bond with O2 gas to produce solid
Mgo. Which of the following reaction equations correctly describes this reaction?
A) 2Mg (s) + O2(g) – Mgo (1)
O B) 2Mg (s) + O2 (g) – 2Mgo (s)
Sey
C) Mg (s) + 202 (g) – Mgo (s)
D) Mg (g) + O2 (s)
-
2MgO (g)
Answer:
Option B. 2Mg(s) + O2 (g) —> 2MgO (s)
Explanation:
From the question given above,
We were told that:
2 solid Mg atoms bond with O2 gas to produce solid MgO.
This can be represented by an equation as follow:
2Mg(s) + O2 (g) —> MgO (s)
Next, we shall balance the above equation as follow:
2Mg(s) + O2 (g) —> MgO (s)
There are 2 atoms of Mg on the left side and 1 atom on the right side. It can be balance by putting 2 in front of MgO as shown below:
2Mg(s) + O2 (g) —> 2MgO (s)
Now, the equation is balanced.
Answer:2 Mg (s)+ O2 (g)= 2MgO(s)
Explanation:
If I was an astronaut the mass would be much larger than earth because, the more mass an object has, the more the object pulls towards it. Mass is the amount of matter that will be everywhere. mass of earth is so big, It creates a gravitational force that can pull objects toward its center. Please help!!!!! Right between "It." and mass I need a good transition word.
Answer:
In my opinion, I think that furthermore might be a good transition word.
hope this helps :)
Explanation:
which organelle helps to break down substances?
Answer:
Lysosomes
Explanation:
I really need this fast
Answer:
b
I think it's me because a ball of golf into some races as it rolls up increases put
How do I do this question?The aluminum cup inside your calorimeter weighs 39.78 g. You add 50.01 g of ice cold water to the calorimeter. You measure the temperature of the calorimeter to be 0.5oC just before your next addition. You then add 50.72 g of hot water and a 49.98 g metal object, all having an initial temperature of 69.5oC. After the calorimeter reaches thermal equilibrium, the final temperature is measured to be 35.9oC.
What is the specific heat of the metal object, in units of J g-1 oC-1.
Assume that:
the calorimeter is completely insulated
the heat capacity of the empty calorimeter is the heat capacity of the aluminum cup: 0.903 J g-1 oC-1.
the density of water is: 1.00 g/mL.
the heat capacity of water is: 4.184 J g-1 oC-1.
Perform all calculations without rounding, but then provide your answer to the correct number of significant figures. Units can be entered as J/(gK)
Answer:
[tex]Cp_{metal}=0.922\frac{J}{g\°C}[/tex]
Explanation:
Hello.
In this problem we must realize that there is heat flow that moves from the hot metal object and the hot water to the cold water and the cold aluminum cup, which allows us to write:
[tex]Q_{cup}+Q_{cold,w}=-(Q_{metal}+Q_{hot,w})[/tex]
Which means that the heat lost be the hot metal object and the hot water is gained by both the cold water and the cold aluminum cup, which can be written in terms of mass, specific heats and change in temperature towards the equilibrium temperature (35.9 °C):
[tex]m_{cup}Cp_{cup}(T_{eq}-T_{cup})+m_{cold,w}Cp_{cold,w}(T_{eq}-T_{cold,w})=-(m_{metal}Cp_{metal}(T_{eq}-T_{metal})+m_{hot,w}Cp_{hot,w}(T_{eq}-T_{hot,w})[/tex]
We need to solve for the specific heat of the metal as shown below:
[tex]Cp_{metal}=\frac{m_{cup}Cp_{cup}(T_{eq}-T_{cup})+m_{cold,w}Cp_{cold,w}(T_{eq}-T_{cold,w})+m_{hot,w}Cp_{hot,w}(T_{eq}-T_{hot,w})}{-m_{metal}(T_{eq}-T_{metal})} \\\\Cp_{metal}=\frac{39.78g*0.903\frac{J}{g\°C}(35.9-0.5)\°C+50.01g*4.184\frac{J}{g\°C}(35.9-0.5)\°C +50.72g*4.184\frac{J}{g\°C}(35.9-69.5)\°C }{-49.98g(35.9-69.5)\°C } \\\\Cp_{metal}=\frac{1271.6J+7407.2J-7130.3J}{-1679.3g\°C} \\\\Cp_{metal}=0.922\frac{J}{g\°C}[/tex]Best regards.
is the scientific method cyclic or linear?
Answer:
Instead of being a linear process, the scientific method is a complex cycle that involves many people and does not follow set steps, but is more free form in nature. Ideas generate new ideas and lead to new hypotheses, and deeper understanding.
Answer:
The answer is
Cyclic...
: )
look at the picture
Answer:
C
Explanation:
If a substance is malleable, it can be hammered flat without breaking
Wavelength measures the length of an
individual color
individual sound
individual wave
all radiation on earth
Answer: individual wave
Hope this helps! :)
PLEASE HELP ME !!!!!!!!!!!!!!
Name: Period; Date:
Problem:
Determine the amount of energy (heat) in Joules and Kcal required to raise the temperature 0f 98.5 grams water from 37.0 0C to 75.0 0C.
Restate the problem (in your own words & all relevant information included).
Model that best represents the problem. Draw and label.
Steps to solve the problem (include formula, known and unknown variables, etc)
Solution and final answer. (show cancellation of units).
Reflection: Must at least have 3 sentences.
Answer:
Explanation:
What best explains whether bromine (Br) or neon (Ne) is more likely to form a covalent bond?
On left, a purple circle labeled Br surrounded by 4 concentric circles. The inner circle has 2 small green spheres. The second circle has 8 small green spheres. The third circle has 18 small green spheres. The fourth circle has 5 small green spheres. On right, a purple circle labeled Ne surrounded by 3 concentric circles. The inner circle has 2 small green spheres. The middle circle has 8 small green spheres. The outer circle has 8 small green spheres.
Bromine forms covalent bonds because it has seven valence electrons, but neon has eight valence electrons and already fulfills the octet rule.
Bromine forms covalent bonds because it has many electron shells, but neon has only two electron shells and is tightly bound to its electrons.
Neon forms covalent bonds because it can share its valence electrons, but bromine has seven valence electrons and can gain only one more electron.
Neon forms covalent bonds because it has only two electron shells, but bromine has many electron shells and will lose electrons in order to fulfill the octet rule.
Mark this and return
Answer:
Bromine forms covalent bonds because it has seven valence electrons, but neon has eight valence electrons and already fulfills the octet rule. Neutral atoms coming together to share electrons.
Hoped this helped
Answer:
the answer is A btw
Explanation:
A student buys a rope at the store. The label on the packaging says that the rope is 2.15 meters in length. The student measures the rope as 1.85m. What is the student’s percent error?
Answer:
30 center meters
Explanation:
2.15-1.85=0.30
What is the volume of “a pencil has a density of .875 g/ml . It has a mass of 3.5 grams
Answer:
The answer is 4 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question
mass of pencil = 3.5 g
density = 0.875 g/mL
So we have
[tex]volume = \frac{3.5}{0.875} \\ [/tex]
We have the final answer as
4 mLHope this helps you
PLEASE PLEASE HELP
3. SEP Analyze Data Suppose you did not want to calculate the precise atomic
mass for one of the elements, such as nitrogen or oxygen. How could you
approximate the value of the atomic mass?
add it up maybe?
Explanation:
The atomic mass of any element can be easily determined with the help of the number of protons and neutrons. You are simply required to add the number of neutrons and protons in order to estimate the atomic mass of any element.
What is Atomic mass?The Atomic mass of an element may be defined as the average mass of the atoms of an element that are significantly measured in the atomic mass unit (amu).
Another method through which you can approximate the value of the atomic mass of any element is that you are simply required to double the value of the atomic number that is known for each specific element.
For example, The atomic number of oxygen is 8, while its atomic mass is 8 × 2 = 16. Similarly, the atomic number of nitrogen is 7, while its atomic mass is 7 × 2 = 14.
Therefore, it is well described above.
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Which method of heat transfer can take place without matter? (3 points)
a
Conduction
b
Convection
c
Insulation
d
Radiation
Answer:
I bealive the answer is D.
What is an isotope and how does their abundance in nature differ from element to element
Answer:
isotopes, there elements with a diffrent type atomic weight then the original, usally due to a higher amout of neutrons than the original. Some Isotopes are just as useable as the normal versions, but in some cases, such as Uranium, they can be even more radioactive than the original form
the substance most likely to be a gas at room temperature is
Answer:
The water
Explanation:
Pls answer! 30 points and brainliest for the correct answer!
Answer: 313.4 I think
Explanation:
sorry if i got it wrong i tried my best
Answer:
it equals up 30 to 35 for me
Explanation:
sorry if its wrong
If an atom has a mass of 40 amu, which of the following MUST be true?
a. There are 20 protons in this atom.
b. There are less than 40 protons in this atom.
c. There are exactly 40 protons in this atom.
d. There are 40 electrons in this atom.
Answer:
b. There are less than 40 protons in this atom.
Explanation:
Hello.
In this case, given the information we have available in the periodic table, we can infer that the number of both protons and electrons of neutral atoms is equal to the atomic number, not the atomic mass which is actually given. Nevertheless, the number neutrons are computed by knowing the atomic mass and the atomic number via:
[tex]neutrons=atomic\ mass -atomic \ number[/tex]
It means that the atomic mass is greater than the atomic number or the amount of both protons and electrons. In such a way, we can infer that the answer is b. There are less than 40 protons in this atom since the number of neutrons must be positive.
Best regards.
1. You return to the car from an all-day shopping spree at the mall.
Your favorite CD, which you left on the dashboard, is now stuck.what could be the experiment?
Answer:
it could be a bad experience
Explanation:
because the left the cd on the dashboard
Write the Lewis structure for sis2
Answer:
N2H4 is straightforward with no double or triple bonds. In the N2H4 Lewis structure the two Nitrogen (N) atoms go in the center (Hydrogen always goes on the outside). Hydrogen (H) only needs two valence electrons to have a full outer shell. In the Lewis structure for N2H4 there are a total of 14 valence electrons.
Figure 5 below shows four abiotic factors of an ecosystem. Choose the
statement that identifies a major characteristic of abiotic factors in
ecosystems.
A. They are all living.
B. There are equal amounts in every ecosystem.
C. They are not alive, never have been alive, and never will be alive.
D. They are impossible to measure.
8. In the nucleus, I tell cells what to do and how to change. 9. The fastest growing organ in humans is the
Answer:
skin is the fastest growing organ in human beings.
Consider the combustion of methane (as represented by the following equation). This is the reaction that occurs for a Bunsen burner, which is a source of heat for chemical reactions in the laboratory.
CH4(g) + 2O2(g) →CO2(g) + 2H2O(g)
For the system at chemical equilibrium, which of the following explains what happens if the temperature is raised?
a. The equilibrium is shifted to the right and the value of K increases.
b. The equilibrium is shifted to the right and the value of K decreases.
c. The equilibrium is shifted to the left and the value of K decreases.
d. The equilibrium is shifted to the left and the value of K increases.
e. The equilibrium is shifted but the value of K stays constant.
Answer:
The correct answer is - option C. The equilibrium is shifted to the left and the value of K decreases.
Explanation:
The combustion of the methane produces water vapor, carbon dioxide when burns in presence of oxygen. This reaction also releases heat and light when combustion occurs.
CH4(g) +2O2(g)-----> CO2(g)+ 2H2O(g) + Heat
As this reaction releases the heat which means it is an exothermic reaction and as if the temperature increase, the equilibrium constant decreases, and as it decreases the equilibrium shifted to the left.
Thus, the correct answer is - option C.
Answer: option choice C
Explanation:
Write a nuclear reaction for the fission of Uranium-235 by bombardment with a neutron.
Answer:
jumm453685ruuhkcswch
How many grams of H2 are needed to react with 47 grams of N2 to produce 200 grams of NH3?
The term mole concept is used here to determine the mass of hydrogen. The mass of hydrogen required to produce 200 g of ammonia is 35.28 g.
What is a mole?One mole of a substance is defined as that quantity of it which contains as many entities as there are atoms exactly in 12 g of carbon - 12. The formula used to calculate the number of moles is:
Number of moles = Given mass / Molar mass
The balanced equation is:
N₂ + 3H₂ → 2NH₃
3 moles of H₂ gives 2 moles of NH₃
The molecular mass of NH₃ is 17 g/mol
n = 200 / 17 = 11.76 mol
1 mole comes from 1.5 moles of H₂
So 11.76 mol comes 1.5 × 11.76 moles H₂ = 17.64 moles of H₂
Mass of H₂ = 17.64 × 2 = 35.28 g
Thus the mass of H₂ needed is 35.28 g.
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What voltage is required to move 2 amps through 20 ohms?
Answer:
v=ir
v=2×20
=40V is the answer
Answer:
a
Explanation:
the answer is a
The decomposition of AB given here in this balanced equation 2AB (g)⟶ A2 (g) + B2 (g), has rate constants of 8.58 x 10-9 L/mol s at 325°C and 2.16 x 10-5 L/mol x at 407°C. Find the activation energy
Answer:
3.24 × 10^5 J/mol
Explanation:
The activation energy of this reaction can be calculated using the equation:
ln(k2/k1) = Ea/R x (1/T1 - 1/T2)
Where; Ea = the activation energy (J/mol)
R = the ideal gas constant = 8.3145 J/Kmol
T1 and T2 = absolute temperatures (K)
k1 and k2 = the reaction rate constants at respective temperature
First, we need to convert the temperatures in °C to K
T(K) = T(°C) + 273.15
T1 = 325°C + 273.15
T1 = 598.15K
T2 = 407°C + 273.15
T2 = 680.15K
Since, k1= 8.58 x 10-9 L/mol, k2= 2.16 x 10-5 L/mol, R= 8.3145 J/Kmol, we can now find Ea
ln(k2/k1) = Ea/R x (1/T1 - 1/T2)
ln(2.16 x 10-5/8.58 x 10-9) = Ea/8.3145 × (1/598.15 - 1/680.15)
ln(2517.4) = Ea/8.3145 × 2.01 × 10^-4
7.831 = Ea(2.417 × 10^-5)
Ea = 3.24 × 10^5 J/mol
The activation energy is 3.24 × 10^5 J/mol
Equation:The activation energy of this reaction can be determined using the equation:
ln(k2/k1) = Ea/R x (1/T1 - 1/T2)
Here
Ea = the activation energy (J/mol)
R = the ideal gas constant = 8.3145 J/Kmol
T1 and T2 = absolute temperatures (K)
k1 and k2 = the reaction rate constants at temperature
Now
First, we need to convert the temperatures in °C to K
So,
T(K) = T(°C) + 273.15
T1 = 325°C + 273.15
T1 = 598.15K
T2 = 407°C + 273.15
T2 = 680.15K
Since, k1= 8.58 x 10-9 L/mol, k2= 2.16 x 10-5 L/mol, R= 8.3145 J/Kmol, we can now determined Ea
So,
ln(k2/k1) = Ea/R x (1/T1 - 1/T2)
ln(2.16 x 10-5/8.58 x 10-9) = Ea/8.3145 × (1/598.15 - 1/680.15)
ln(2517.4) = Ea/8.3145 × 2.01 × 10^-4
7.831 = Ea(2.417 × 10^-5)
Ea = 3.24 × 10^5 J/mol
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A homerun in a baseball game was measured at 450 feet. How many meters is this equal to?
Answer:
137.16
Explanation:
Which explains how the technology of probeware has increased scientific inquiry?
Answer:
~ Probeware can collect large amounts of data in a short amount of time.
~Probeware can display data quickly.
~Probeware can collect data that is very precise.
Probeware can be used to map all parts of the universe. WRONG.WRONG.
~Probeware can store large amounts of data in a small space.
~Probeware can analyze data
Why doesn't the outer electron on the potassium atom experience the full charge of the protons in the nucleus (+19)?
I believe the answer is C. There are 19 electrons shielding it from the nucleus