[tex]HF \rightleftharpoons H^{+} + F^{-}\\[/tex]
We have 1.5 M HF in the beginning and 0 M [tex]H^{+}[/tex] and [tex]F^{-}[/tex]
We know that there's gonna be a decrease of x M on [tex]HF[/tex] and an increase of x M on [tex]H^{+}[/tex] and [tex]F^{-}[/tex].
We also find in chemistry tables that [tex]K_{a}(HF) = 6.8 \cdot 10^{-4}[/tex]
[tex]K_a = \frac{[H^+] \cdot [F^-]}{[HF]}\\6.8 \cdot 10^{-4} = \frac{x \cdot x}{1.5 - x} \\6.8 \cdot 10^{-4} = \frac{x^2}{1.5}\\6.8 \cdot 10^{-4} \cdot 1.5 = x^2\\x^2 = 1.02 \cdot 10^{-3}\\x = 0.0319\\pH = -\log{0.0319}\\pH = 1.5[/tex]
When a solid dissolves in water, heat may be evolved or absorbed. The heat of dissolution (dissolving) can be determined using a coffee cup calorimeter. In the laboratory a general chemistry student finds that when 22.24 g of Cs2SO4(s) are dissolved in 106.70 g of water, the temperature of the solution drops from 25.62 to 22.57 °C. The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.65 J/°C. Based on the student's observation, calculate the enthalpy of dissolution of Cs2SO4(s) in kJ/mol. Assume the specific heat of the solution is equal to the specific heat of water.
Answer:
26.85kJ/mol is the heat of dissolution of Cs₂O₄
Explanation:
The process of dissolution of Cs₂SO₄ in water occurs as follows:
Cs₂O₄(s) → 2Cs⁺(aq) + SO₄²⁻(aq) + ΔH
Where ΔH is the change in heat per mole of Cs₂O₄
The first we can see is ΔH > 0 because heat is absorbed (Temperature is decreasing) when the reaction occurs.
Now, the change in heat of reaction is:
q = Heat calorimeter + Heat solution
q = ΔT*1.65J/°C + S*m×ΔT
Where q is the heat of reaction.
ΔT is change in temperature: 25.62°C - 22.57°C = 3.05°C
S is specific heat of solution = Specific heat water = 4.184J/g°C
m is mass of solution = 22.24g + 106.70g = 128.94g
Replacing, heat of reaction is:
q = 3.05°C*1.65J/°C + 4.184J/g°C*128.94g×3.05°C
q = 1650J are absorbed when 22.24g of Cs₂O₄ reacts
Moles of 22.24g of Cs₂O₄ are - Molar mass: 361.87g/mol-:
22.24g * (1mol / 361.87g) = 0.06146 moles
That means, when 0.06146 moles of Cs₂O₄ react, the heat absorbed is 1650J. That means the heat absorbed per mole of Cs₂O₄ (Enthalpy of dissolution) is:
1650J / 0.06146 moles = 26847J / mol =
26.85kJ/mol is the heat of dissolution of Cs₂O₄
What is the volume of a piece of aluminum if the mass is 150g and the density.is 2.70 g/cm3
Answer:
The answer is
55.56 cm³Explanation:
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 aluminum = 150 g
density = 2.7 g/cm³
The volume is
[tex]volume = \frac{150}{2.7} \\ = 55.5555555...[/tex]
We have the final answer as
55.56 cm³Hope this helps you
Formula: v = m/d
v = volume
m = mass
d = density
We are given the mass and density, so we can solve for the volume.
v = 150/2.7
v = 55.555...mL
Best of Luck!
_________energy from the sun
Answer:
radiant energy, solar energy
During nuclear fusion, radiant energy and solar energy from the core of the Sun is released. Hope it helps!
What is the oxidation state of Cobalt (iii)
A.+2
B.+5
C.-3
D.+3
Answer:
D. +3
Explanation:
You're Welcome
Which of the following are examples of sampling bias
Select all that apply,
A wildlife biologist measuring average deer size only chooses male deer,
which tend to be larger than female deer,
A plant ecologist wants to know which insects visit certain flowers,
but only samples in the morning around 10:00am.
A marine biologist studies coral reef populations, and samples the same
reef location every day because it has more fish,
A forest ecologist wants to study bird populations so she sets up an
observation station next to the office because it's convenient
A marine biologist uses tools to carefully collect a random sample of
anemones at regular intervals along a transect line
Answer:
the first and the third one.
Statements that serve as examples of sampling bias are:
A wildlife biologist measuring average deer size only chooses male deer, which tend to be larger than female deer.
A plant ecologist wants to know which insects visit certain flowers,but only samples in the morning around 10:00am.
A marine biologist studies coral reef populations, and samples the same
reef location every day because it has more fish.
A forest ecologist wants to study bird populations so she sets up an
observation station next to the office because it's convenient
Sampling bias can be regarded as a bias whereby a sample is collected, among these samples some members of the intended population will possess lower or higher sampling probability compare to others at the end. Biased sample of a population usually resulted when all individuals, or instances don't have selection.For instance, wildlife biologist that want to measure average deer size, he then choose the male only which is usually larger than the female, his sampling will result to sampling biasTherefore, option the last option is correct.
Learn more at:
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PSYCHOLOGYWhich of the following statements is not correct concerning the relationship between attention and perception? Focusing one’s attention on something in the environment is necessary in order to perceive it. Individuals have the ability to focus attention on a specific stimulus in the midst of surrounding activity. Whether or not people perceive information as meaningful influences their attention to it. Individuals can easily detect changes in the environment when they are absorbed in a task.
Answer:
The answer is Individuals can easily detect changes in the environment when they are absorbed in a task.
Explanation:
The statements is not correct concerning the relationship between attention and perception is that individuals can easily detect changes in the environment when they are absorbed in a task.
What is psychology?Psychology is defined as the scientific discipline that studies mental state and processes and behavior in human and other animals.
It can also be defined as the scientific study of mind and behavior.
Environment is defined as the sum total of all the living and non living elements and there effect that influences human life.
Thus, the statements is not correct concerning the relationship between attention and perception is that individuals can easily detect changes in the environment when they are absorbed in a task.
To learn more about psychology, refer to the link below:
https://brainly.com/question/10980588?
#SPJ2
ASAP 40 POINTS PLUS BRAINLIEST PLZ IM ON TIMER
How does altitude affect climate patterns in a region?
Areas at high elevations have cooler temperatures.
Air continues to warm as it rises to a higher elevation.
Tropical regions do not have many differences in altitude.
High-altitude areas have less variation in seasonal temperatures.
Answer:
Answer is A
Areas at high elevations have cooler temperatures.
I presume you're doing earth science B?
Answer: It is A) Areas at high elevations have cooler temperatures.
Explanation: I got it correct.
A sample of helium has an initial
temperature of 78° C. When the
temperature is lowered to 18,0° C, the
volume of helium becomes 285 mL,
What was the initial volume of the
helium in mL?
Answer:
3460 mL
Explanation:
We are given:
T(i) = 351 k T(f) = 289 k
V (i) = v mL V(f) = 285 mL
Using the gas equation:
PV = nRT
Since Pressure (P) , number of moles (n) and R is the universal gas constant
We can say that V/T = k (where k is a constant)
Hence, we can say that:
V(i) / T(i) = V(f) / T(f)
Replacing the values
v / 351 = 285 / 289
v = 3460 mL
If you have any doubt about this answer, feel free to comment
Select all that apply. When the products of a reaction have more energy than the reactants: The reaction is endothermic. The reaction is exothermic. The reactants gave up energy.
Answer:
the reaction is exothermic
Explanation:
heat will be produced from the reaction
Answer:
The reaction exothermic
Reactants gave up energy ;) Have a good day
Acetylsalicylic acid (ASA) _____.
A.is used to treat acne
B.reduces pain and fever
C.is used as an anesthetic
D.causes acid rain
Answer:
b. reduces pain and fever
✅Acetylsalicylic acid (ASA) _____. reduces pain and fever
IamSugarbee
How many electrons are in an atom of elemental sodium?
equal to the number of neutrons
equal to the number of protons
equal to the number of protons and neutrons
Answer:
its the second option
equal to the number of protons
Explanation:
took the test
Answer:
equal to the number of protons
Explanation:
2021 edge
For determining the toxicity of different compounds, the concept of LD50, the lethal dose for 50% of test subjects is used. The LD50in rats for potassium cyanide is 1.52mg per 1 kg of body weight. Assuming the same LD50for humans, determine the molarity of potassium cyanide in a 355 mL (12 ounces) drink that would correlate to the LD50for a person having a mass of 170.0 lbs.
Answer:
Explanation:
LD 50 in rat = 1.52 mg per kg of body weight .
Body weight of man = 170 lbs = 170 / 2.2 kg = 77.27 kg
LD = 1.52 x 77.27 mg = 117.45 mg = .11745g
molecular weight of potassium cyanide = 65.12 g
moles of potassium cyanide = .11745 /65.12 = .0018 moles
.0018 in .355 L
molarity of solution = .0018 / .355 = .005 M .
When liquid gold becomes a solid, its particles get closer together. Which best describes what happened to the gold?
the conservation of magnetism
the change in solubility in a physical change
the change in melting point in a physical change
the rearrangement of particles in a physical change
Answer:
The rearrangement of particles in a physical change.
Explanation:
When things are liquid the particles tend to be spread out because they aren't tightly compacted as they would be with a solid. So when liquid gold is changing from a liquid to a solid the properties are changing and the particles in the gold are getting closer together.
Answer:
D is correct answer
Explanation:
which two chemists organized elements based on properties such as how the elements react or whether they are solid or liquid
Answer: Dmitri Mendeleev and Henry Moseley developed their periodic tables about forty years apart. During that time, many discoveries in chemistry were made.
Explanation:
Hope this helps
What are the main differences between plang and animal cells
What is the correct relationship between a molecule and a compound? *
2 points
All molecules are compounds, but not all compounds are molecules.
All compounds are molecules, but not all molecules are compounds.
Only compounds make a molecule.
Only molecules make a compound.
Answer:
All compunds are molecules, but not all molecules are compounds.
Explanation:
Not all molecules are made of compounds because some molecules only have one element, of only one type of atom.
Where are the instructions that tell the cell everything it needs to survive?
mitochondrion
nucleolus
endomembrane system
ribosome
Answer:
Nucleolus
Explanation:
It holds the DNA
Answer:
Nucleolus
Explanation:
I did the test. You’re welcome. ✌️
Cl2 reacts with the element Sr to form an ionic compound. Based on periodic properties, identify a molecule, X2, that is likely to to react with Sr in a way similar to how Cl2 reacts with Sr. Justify your choice.
Answer:
The bromine molecule, Br2 will likely react with Sr in a similar way to chlorine molecule, Cl2.
Explanation:
Chlorine belongs to group 7 of the periodic table. Elements in this group are known as halogens. Its molecule has the formula Cl2. The next element in the group after chlorine is bromine. Its molecule has a formula Br2. It has similar properties as chlorine, therefore, it would react with Strontium in a similar way to chlorine.
Elements belonging to the same group of the periodic the table have similar chemical properties as they contain the same number of valence electrons. Chlorine and Bromine both belong to group 7 of the periodic table and each have seven valence electrons. They both react with metals to form salts even though reaction with chlorine is more vigorous as it is more reactive than bromine. They both form negatively-charged ions with a charge of -1.
Reaction of Strontium with the halogens:
With chlorine: Sr + Cl2 ---> SrCl2
With bromine: Sr + Br2 ---> SrBr2
The salts formed are both crystalline salts with high melting and boiling points.
A molecule X₂ that will likely react with Sr in a way similar to how Cl₂ reacts with Sr is I₂
Strontium, Sr is a group 2 element.
Chlorine, Cl is a group 17 element. All members of this group have 7 valence electrons and as such, they have similar chemical properties. Other members of this group include fluorine (F), bromine (Br), iodine (I).
Chlorine molecule (Cl₂) reacts with strontium (Sr) as follow:
Cl₂ + Sr —> SrCl₂Iodine molecule (I₂) will also reacts in the same way since they are in the same group.
I₂ + Sr —> SrI₂Learn more: https://brainly.com/question/4725757
What is the net ionic equation for a reaction between HCl and NaOH
Answer:
What is the net ionic equation for a reaction between HCl and NaOH?
Explanation:
A salt is a neutral ionic compound. Let's see how a neutralization reaction produces both water and a salt, using as an example the reaction between solutions of hydrochloric acid and sodium hydroxide. The overall equation for this reaction is: NaOH + HCl → H2O and NaCl
Hope that helped.
Answer: H+(aq) + OH−(aq) → H2O(l)
Explanation: The net ionic equation is H+(aq) + OH−(aq) → H2O(l). The complete ionic equation will show all aqueous substances as ions while pure liquids and solids will be shown in their molecular form as that is how they exist in solution.
ou are performing a ton test for household ammonia. you place 150 ml of distilled water in a 500 ml beaker first. you added 1 ml of the household ammonia and add distilled water to top up a total volume of 200 ml, the odor can be detected in this dilution. take 50 ml of the above diluted sample as an intermediate sample and continually dilute it to 200 ml and the odor is still detectable. you decided to reduce to 10 ml of the first time diluted household ammonia and the odor was just detectable. how much is the ton of the household ammonia
Answer: the ton of the household ammonia is 4000
Explanation:
Given that;
the initial ammonia in 200mL sample = 1ml
also decided to reduce to 10 ml of the first time diluted household ammonia and the odor was just detectable
10ml ammonia content = 1/200 * 10 = 1/20ml
we know that total volume is 200 ml
therefore the TON of household ammonia will be = total volume / volume of ammonia
TON = total volume / volume of ammonia
we substitute
TON = 200 / (1/20)
TON = 200 / 0.05
TON = 4000
therefore the ton of the household ammonia is 4000
What is the difference between mass number and average atomic mass?
(choose all that apply)
A: Mass number is a whole number, average atomic mass is a decimal number
B: Mass number is protons + neutrons, average atomic mass is all the different protons + neutrons
C: Mass number is the mass of one element, average atomic mass is the number of
protons
D: There is no difference
Answer:
the answer is c. I think
Explanation:
Calculate the volume of an object (in mL) if the density of the object is 4.08 g/mL and the mass of the object is 10.02 g.
Round your answer to one decimal.
Answer:
The answer is 2.5 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 object = 10.02 g
density = 4.08 g/mL
The volume of the object is
[tex]volume = \frac{10.02}{4.08} \\ = 2.4558823...[/tex]
We have the final answer as
2.5 mL to one decimal placeHope this helps you
Why are the so many volcanoes in california help pls!!
Explanation:
During and after an explosive or effusive eruption volcanic hazards are still a concern. Unstable ground, noxious gas emissions, and intense heat from fumaroles (steam vents) and hot springs are dangerous. Loose volcanic debris on the flanks of the volcano can be mobilized by heavy rainfall or melting snow and ice, forming powerful floods of mud and rock (lahars) resembling rivers of wet concrete. These can rush down valleys and stream channels, destroying roads and bridges and carrying away entire buildings
hope the answer is correct
The most common form of elemental sulfur is S8, in which eight sulfur atoms linked in a ring of single bonds. At high temperature, in the gas phase, S8 can break apart to give S2, the sulfur analog of molecular oxygen:
S8(g) 4S2(g) ΔH = +239 kJ at T = 800 K
Using the appropriate data in Table 3-2 S-S 240 calculate the S=S double-bond energy (in kJ/mol) in S2(g).
Answer:
Explanation:
In S₈ , there are 8 single bonds which breaks up first . Energy absorbed
= 8 x 240 = 1920 kJ
In S₈ four double bonds of S₂ are formed . Let bond energy be x . In this process energy will be released . energy released in four S₂ molecules formed = 4 x
Given
1920 + 4x = 239
4x = 239 - 1920
x = - 420.25 kJ .
So bond energy of S₂ = 420.25 kJ .
basically everything is in the picture, and i dont really understand please help.
Hydrogen gas at a pressure of 740. mmHg has a volume of 2.00 L at a temperature of 25.0°C. What is the temperature of this gas at 3.50 L and
standard pressure?
Answer:
The final temperature of hydrogen gas is 537.63 K.
Explanation:
Given data:
Initial volume = 2.00 L
Initial pressure = 740 mmHg (740/760 = 0.97 atm)
Initial temperature = 25 °C (25 +273 = 298 K)
Final temperature =?
Final volume = 3.50 L
Final pressure = standard = 1 atm
Formula:
According to general gas equation:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
Solution:
P₁V₁/T₁ = P₂V₂/T₂
T₂ = P₂V₂T₁ / P₁V₁
T₂ = 1 atm × 3.5 L × 298 K / 0.97 atm × 2.00 L
T₂ = 1043 atm .L. K / 1.94 atm. L
T₂ = 537.63 K
How many moles are in 8.8 x 1024 atoms of magnesium?
Answer:
15 mol Mg
Explanation:
Step 1: Find conversions
Avagadro's Number: 6.022 × 10²³
Step 2: Use Dimensional Analysis
[tex]8.8(10)^{24} \hspace{3} atoms \hspace{3} Mg(\frac{1 \hspace{3} mol \hspace{3} Mg}{6.022(10)^{23} \hspace{3} atoms \hspace{3} Mg} )[/tex] = 14.6179 mol Mg
Step 3: Simplify
We have 2 sig figs.
14.6179 mol Mg ≈ 15 mol Mg
5. 1.00 mol HNO3 is treated with 4.47 g of magnesium. Calculate the number of moles of
HNO3 after all the metal has reacted. The unbalanced reaction is
HNO3 (aq) + Mg(s) + Mg(NO3)2 (aq) + H2(g)
a. 0.632 mol b. 0.184 mol c. 1.00 mol d. OM(all HNO3 used up)
Answer:
The balanced equation is:
2 HNO3 + Mg ---> Mg(NO3)2 + H2
From the equation, we can see that we need twice the moles of HNO3 than the moles of Mg
Moles of Mg:
Molar mass of Mg = 24 g/mol
Moles = Given mass / Molar Mass
Moles of Mg = 4.47 / 24 = 0.18 moles (approx)
Hence, 2(moles of Mg) = 0.36 moles of HNO3 will be consumed
Number of moles of HNO3 after the reaction is finished is the number of unreacted moles of HNO3
Unreacted moles of HNO3 = Total Moles - Moles consumed
Unreacted moles of HNO3 = 0.64 moles (approx)
Since we approximated the value of moles of Mg, the value of remaining moles of HNO3 will also be approximate
From the given options, we can see that 0.632 moles is the closest value to our answer
Therefore, 0.632 moles will remain after the reaction
97.2 kJ of heat is added to a 12.0 kg block or iron. what is the temperature change of the block?
Answer:
[tex]\Delta T=18.24\°C[/tex]
Explanation:
Hello,
In this case, since the equation for computing the heat in terms of mass, specific heat and temperature change is:
[tex]Q=mCp\Delta T[/tex]
For the given heat and mass, and considering the specific heat of iron to be 0.444 kJ/(kg°C), the resulting temperature change is:
[tex]\Delta T=\frac{Q}{mCp}=\frac{97.2kJ}{12.0kg*0.444\frac{kJ}{kg\°C}}\\ \\\Delta T=18.24\°C[/tex]
Best regards.
Explain the relevance of atomic particles in healthcare setting
Answer:
The relevance of atomic particles in healthcare setting is that atomic particles contain the core properties of an organism or compound.
Having a good knowledge of it means that designing of drugs and treatment is easier as a result of modifications done to the atomic particles to enable an accurate solution in areas of healthcare and Drug production
