Answer:
9.36g of CaF2 is presnt in the solution.
Explanation:
CaF2 molar concentration is 0.15mol in 1.25l of solution.
1. Convert this to the standard concentration in mol/dm3:
1dm3 = 1 L
0.15mol = 1.25 dm3
x =1 dm3
0.15 = 1.25 x
x = 0.15/1.25
x = 0.12 mol/dm3
2. Calculate the relative molecular mass of CaF2
Ca= 40, F =19
RMM = 40 + 19 *2
RMM = 40+ 38
RMM = 78g/mol
3. Calculate the concentration in g/dm3
conc. in mol/dm3 = conc in g/dm3 / RMM
conc in g/dm3 = conc in mol/dm3 * RMM
= 0.12mol/dm3 * 78g/mol
= 9.36 g/dm3
So therefore, 9.36g of CaF2 is presnt in the solution.
the string of a bow and arrow is pulled tight
Answer:
I'm not sure that is the full question can you show a picture or something?
the string of a bow and arrow is pulled tight with Elastic
The correct option is (c).
When the string of a bow and arrow is pulled tight, the energy stored in the string is primarily due to its deformation, which is a characteristic of elastic potential energy.
c. Elastic potential energy arises from the deformation of an object, such as stretching a spring or pulling a rubber band. When the string of the bow and arrow is pulled tight, it undergoes deformation, storing potential energy in the form of elastic potential energy. This energy is then released when the string is released, propelling the arrow forward.
a. Gravitational potential energy refers to the energy associated with an object's position in a gravitational field. While gravity does play a role in the bow and arrow system (as it affects the trajectory of the arrow), the energy stored in the string itself is not primarily gravitational potential energy.
b. Chemical potential energy refers to the energy stored in chemical bonds, which is released during a chemical reaction. The action of pulling the string tight does not involve any chemical reactions, so it is not chemical potential energy.
d. Electric potential energy refers to the energy stored in an electric field due to the position of charged particles. The energy stored in the string of a bow and arrow is not related to electric potential energy.
complete question given below:
The string of a bow and arrow is pulled tight with?
a.Gravitational
b.Chemical
c.Elastic
d.Electric
scientists have discovered a pill that, if taken once a day, can reduce chest pains. what would a reviewing committee MOST LIKELY do before approving this pill for public use?
A) The committee would require no further explanation or experimentation
B) The committee would conduct many trials using actual patients to determine the drug's success rate.
C) The committee would conduct a few trials with actual patients and then evaluate the drug's success rate.
D) Not wanting to risk patients, the committee would conduct other types of research on the drug and then make a decision .
A reviewing committee would conduct extensive clinical trials involving actual patients to ensure the new pill's safety and effectiveness before it can be approved for public use. The FDA requires this rigorous testing process to establish the drug's success rate compared to a control group.
Explanation:Before approving a pill for public use that claims to reduce chest pains, a reviewing committee would MOST LIKELY conduct many trials using actual patients to determine the drug's success rate. This involves a series of large-scale experiments and clinical trials to ensure the drug is safe and effective. The trials would compare the outcomes of participants taking the medication against a control group that does not take the medication. Additionally, the FDA requires significant data from these trials to consider approving the drug for market.
Testing the efficacy of a drug is a thorough process that includes gathering enough data to compare experimental and control groups, assessing statistically significant differences in outcomes, and evaluating the drug's safety through careful monitoring by a pharmacovigilance system.
Final answer:
A reviewing committee would most likely conduct many clinical trials with actual patients to determine the success rate and safety of a new pill for reducing chest pains before it is approved for public use.
Explanation:
Before approving a new drug for public use, a reviewing committee would most likely opt for conducting rigorous clinical trials involving actual patients. The correct answer is B) The committee would conduct many trials using actual patients to determine the drug's success rate. The process includes closely monitoring the drug's efficacy in treating the targeted condition, its overall safety, and any potential side effects. These trials are divided into different phases, with Phase 3 clinical investigation being particularly crucial as it assesses the risk versus benefit of the new pharmaceutical on a large scale, involving hundreds to thousands of patients.
Only when there is substantial evidence supporting the new treatment's benefits, and the results can be replicated, does the committee consider the drug to be supported by evidence. The approval process is thorough and can take several years, involving not only the participation of physicians and chemists but also adherence to guidelines for testing the drug's toxicity and impact on human health.
What is the proper way to find the Volume of an irregular shaped solid object?
A) triple beam balance
B) water displacement
C) L x B x H
D) 1/2 (height x length x width)
Answer:
B) water displacement
Explanation:
C and D are incorrect because they are formulas to find volume for specific shapes. That wouldn't work here since you have an irregularly shaped solid object.
A is incorrect because a triple beam balance is used to find mass.
Final answer:
To determine the volume of an irregular shaped solid object, the correct method is water displacement, which measures the volume of water the object displaces when submerged.
Explanation:
The proper way to find the volume of an irregular shaped solid object is B) water displacement. Unlike regular solids, which can be calculated geometrically using formulas such as Length x Width x Height for rectangular prisms, or πr²h for cylinders, irregularly shaped objects do not conform to simple mathematical formulas. The water displacement method involves submerging the object in water and measuring the volume of water displaced, which equals the volume of the object. This technique is based on Archimedes' principle, which states that the volume of the fluid displaced by an object is equal to the volume of the object itself.
Which of the following is the best definition of radioactive decay?
O
A. Radioactive decay is the loss of mass that occurs when an atom
is formed.
) B. Radioactive decay is the splitting of a nucleus
amounts of energy.
O
C. Radioactive decay is the release of energy resulting from a
chemical reaction.
O
D. Radioactive decay is the spontaneous breakdown of a nucleus into
smaller parts.
Answer:
Radioactive decay is the spontaneous breakdown of a nucleus into smaller parts
Explanation:
Both bacteria and rocks split to give rise to more of their kind. Why are bacteria said to reproduce, but rocks are not?
A.
Bacteria can move on their own, but rocks cannot.
B.
Bacteria do not need an external force to help them reproduce, but rocks must be broken apart.
C.
Bacteria form identical cells, but rocks form new rocks of different sizes and shapes.
D.
Bacteria pass down genetic material to new bacterial cells, but rocks do not.
Answer:
b
Explanation:
Which of these compound interest options will give you the highest ending balance?
Compound monthly
Compound every other month
Compound every six months
Compound annually
Find the initial temperature of Aluminum if 35 g of it produces 781.2 Joules at the final temperature of 44.3 ºC.
Answer:
T initial = 19.55°C
Explanation:
Given data:
Mass of Al = 35 g
Energy produces = 781.2 J
Final temperature = 44.3°C
Initial temperature = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Specific heat capacity of Al is 0.902 J/g.°C
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = Final temperature - initial temperature
Q = m.c. ΔT
781.2 J = 35 g×0.902 J/g.°C× (T final - T initial)
781.2 J = 35 g×0.902 J/g.°C× (44.3°C -T initial )
781.2 J = 31.57 j/°C× (44.3°C -T initial )
781.2 J/ 31.57 j/°C = (44.3°C -T initial )
24.75°C = (44.3°C -T initial )
24.75° - 44.3°C = -T initial
T initial = 19.55°C
What type of plate motion (together, apart, or sliding) has occurred at the Himalayas?
Choose all the answers that apply.
Electrons _____.
have a positive charge
are found in the nucleus
orbit around the nucleus
have a negative charge
Electrons have a negative charge and orbit around the nucleus, while protons have a positive charge and are found in the nucleus. Neutrons have no charge and are also found in the nucleus with protons.
I hope this helps! If you have any doubts, feel free to ask.
your answer is C and D
Jamal does not produce enough insulin to regulate his blood sugar. What part of the endocrine system is most likely being affected?
Adrenalgland
Pancreas
Pituitary gland
Testes
Answer:
B pancreas, since the pancreas secretes insulin
Explanation:
Answer:
pancreas
Explanation:
During absorption, light and UV energy get transformed into ______ energy and radiates in the form of _______.
Question 3 options:
thermal, heat
electromagnetic, nuclear
potential, kinetic
electrical, heat
Sulfur has 4 isotopes listed below. Using a periodic table, which isotope is most likely to be the most common isotope? A) sulfur-32 B) sulfur-33 Eliminate C) sulfur-34 D) sulfur-35
Answer:
A) sulfur - 32
Explanation:
In periodic table you can see that S has average atomic mass = 32.06
It is closest to 32, that means that most of the atoms are isotopes sulfur-32.
The most common isotope of sulfur is sulfur-32 (32S), as it has the highest natural abundance among sulfur isotopes at 95.02% and aligns with the atomic mass listed on the periodic table.
Using a periodic table, the most common isotope of sulfur can be determined to be sulfur-32 (32S). This is because the weighted average of sulfur's atomic mass on the periodic table closely aligns with the mass number of sulfur-32, indicating its high natural abundance. To confirm, the major isotopes of sulfur are 32S with a 95.02% abundance, 33S with a 0.75% abundance, 34S with a 4.21% abundance, and 36S with a 0.02% abundance. Therefore, the most common isotope of sulfur is sulfur-32 (32S), which coincides with option A in the question provided.
1. Determine the acid type for HBr.
O Brønsted-Lowry
O Ahrrenius
O Lewis
not a base
Answer:
Bronsted-Lowry
Explanation:
brainliest please ?
A sound wave with a wavelength of 2.5 m travels 660 m in 2 s. Calculate the frequency of the
wave.
265
Explanation:
660 divided by 2.5 equals 265. The frequency is 265.
Answer:
132Hz
Explanation:
the explanation is in the picture
please like and Mark as brainliest
23 ml of oxygen collected over water and has a pressure of 636 mmhg at 23 c.what is the pressure of the dry gas at stp
Answer : The pressure of the dry gas at stp is, 0.602 mmHg
Explanation :
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,
[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 636 mmHg
[tex]P_2[/tex] = final pressure of gas = ?
[tex]V_1[/tex] = initial volume of gas = 23 mL = 0.023 L
[tex]V_2[/tex] = final volume of gas at STP = 22.4 L
[tex]T_1[/tex] = initial temperature of gas = [tex]23^oC=273+23=296K[/tex]
[tex]T_2[/tex] = final temperature of gas at STP = [tex]0^oC=273+0=273K[/tex]
Now put all the given values in the above equation, we get:
[tex]\frac{636mmHg\times 0.023L}{296K}=\frac{P_2\times 22.4L}{273K}[/tex]
[tex]P_2=0.602mmHg[/tex]
Therefore, the pressure of the dry gas at stp is, 0.602 mmHg
Click to review the online content. Then answer the question(s) below, using complete sentences. Scroll down to view additional
questions
Online Content: Site 1
What resource is often compromised due to mining?
Answer:
Coal mining can compromised a lot of our resources one of it is the soil. It is because it eliminates the nutrients of the soil that can affect the vegetation, it destroys the wildlife and habitat. Also, it changes permanently the topography of the area mined.
Explanation:
edge 2020 just did it
One resource that is often compromised due to mining is water, as mining have significant effect on quality and quantity of water.
Resources are anything that can be used to satisfy a need or want. Resources can be natural, such as land, water, minerals, and wildlife, or they can be human made, such as tools, machines, buildings, and infrastructure.
Mining activities can have significant impacts on water quality and quantity, especially in areas with limited water resources or sensitive ecosystems.
Water can become contaminated by chemicals and heavy metals used in mining, such as cyanide, sulfuric acid, and mercury, which can have harmful effects on aquatic life and human health. Mining can also consume large amounts of water for processing and dust suppression, which can exacerbate water scarcity and competition with other users, such as agriculture and urban areas.
Therefore, mining can have significant impacts on water resources, which are essential for human health, ecosystem functioning, and economic development.
Learn more about resources here:
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I NEED ANSWER TONIGHT PLZ!!!! :(
Which condition results in an activation energy that allows the reaction to occur more easily?
reducing the concentrations of reactant molecules
decreasing the temperature
decreasing the surface area of the particles
adding a catalyst
Answer:
I think adding a catalyst
Explanation:
From what I found, any of the first 4 don't work, reducing the concentrations of reactant molecules just decreases the chances of it reacting, decreasing the temperature does more or less the same, as it takes away energy, decreasing the surface area of the particles does more or less nothing in this situation, but for a reaction to occur, you need to add energy, which only the catalyst does. good luck!
What is the Bohr effect?
why is the concentration of helium increased in some gas mixtures that divers breath in order to reduce the partial pressure of oxygen?
Answer:
Because of oxygen toxicity.
Explanation:
Oxygen toxicity.
Oxygen has been known to cause central nervous system (CNS) toxicity when the pressure gets higher. This toxicity can cause convulsions, and this can cause the diver to drown.
The current standard maximum safe oxygen working pressure is 1.4 atm ppO2. This is equal to 56.5m/185′ when breathing air (21% O2 / 79% N). Below that depth the fraction of oxygen in a breathing gas must be reduced, and in order to maintain this maximum pressure of 1.4 ppO2, Helium must be added.
3. A student constructs a coffee cup calorimeter and places 50.0 mL of water into it. After a brief period of stabilization, the temperature of the water in calorimeter is determined to be 19.1 °C. To this is added 50.0 mL of water that was originally a temperature of 54.9 °C. A careful plot of the recorded temperature established T0 as 31.3 °C. What is the calorimeter constant (J/°C)?
The calorimeter constant is 816.800 J/degree.
Explanation:
Data given:
volume of cold water = 50 ml
initial temperature of the cold water t1 = 19.1 degrees
volume of hot water = 50 ml
temperature of hot water t2 = 54.9 degrees
change in temperature t3= 31.3 degrees
calorimeter constant = ?
energy gained by cold water = energy lost by hot water
q hot water = 50 x 4.184 x (54.9-31.3)
q hot water = 50 x 4.184 x 23.6
= 4937.9 cal/degree
q cold water = 50 x 4.184 x (31.3-19.1)
q cold water = 2552.24 cal/deg
FINAL ENERGY = qhot water - q cold water
final energy = 4937.9 - 2552.24
final energy = 2385.66 cal/deg
calorimeter constant = [tex]\frac{final energy}{t3-t1}[/tex]
putting the values:
calorimeter constant = [tex]\frac{2385.66}{12.2}[/tex]
CALORIMETER CONSTANT = 195.22 J/deg
to convert in joules/degree multiply the value with 4.184
= 195.22 x 4.184
= 816.800 J/deg
If you increase the distance between two objects, the gravitational force between the two objects ____________.
Hi:) for questions 8 & 9 , anyone able to explain why nitrogen is N2 instead of N. also why is chlorine cl2 instead of c1? Thank you!
Answer:
Because both of them are Diatomic molecules.
Explanation:
Which substances are most likely acids? Check all that apply.
O CHA
OHI
NH3
HNO3
O
NaCl
Answer:
HNO3 is nitric acid. NH3 is ammonia, NaCl is common salt. O is an atom of oxygen. No idea about remaining.
Answer:
HI and HNO3 are acids
Explanation:
What happens to particles when heat is removed from them?
Question 7 options:
They speed up and spread out
They stop moving They stop moving
They slow down and get closer together
They move closer together and speed up
SHOW ANSWER
Answer:
they slow down and get close together
Explanation:
low temperature lowers kinetic energy in particles hence they slow down and get close together thereby causing shrinking of the particles
Answer:
They slow down and get closer together
Explanation:
4Na + O2 —> 2Na2O
In this chemical reaction, how many moles of Na2O will be produced if 2.90 moles of Na react completely? Express answer to three significant figures.
Answer:
3.91g
Explanation:
1. Use the equation mol = mass/Mr (Molecular Formula)
2. Use the information you have and put it into the formula 2.9/23 = 0.1260869565
3. Multiply 0.1260869565 by 62 (molecular formula of Na2O) - Formula rearranged to mass = mol × Molecular formula = 7.817391303
4. Divide by two to get two moles, as shown in the chemical equation
5. 3.9086956515
6. 3.91g to three significant figures
For the balanced equation shown below, if the reaction of 0.112 grams of
H2 produces 0.745 grams of H20, what is the percent yield? Fe3O4 + 4H2 -> 3Fe
+ 4H2O
74.5%
84.5%
94.5%
092.2%
Answer:
The answer is 74.5%.
Explanation:
As we know that % yield= [tex]\frac{actual yield}{theoretical yield}[/tex] x 100%.
Therefore,
Step 1 Calculate Theoretical yield:
0.112[tex]H_{2}[/tex] x [tex]\frac{1 mol H_{2} }{2.016 g of H{2} }[/tex] x [tex]\frac{4 mol H_{2}O }{4 mol H_{2} }[/tex] x [tex]\frac{18.02 g H_{2}O }{1 mol H_{2}O}[/tex] = 1.001 g [tex]H_{2}O[/tex]
Now Step 2
% yield = [tex]\frac{actual yield}{theoretical yield}[/tex] x 100% = [tex]\frac{0.745g}{1.001g}[/tex] = 74.5%
Final answer:
To calculate the percent yield, compare the actual yield of H2O (0.745 grams) to the theoretical yield determined by stoichiometry and molar masses of reactants and products.
Explanation:
The student is asking how to calculate the percent yield of a chemical reaction. In this chemical reaction, 0.112 grams of hydrogen (H2) produces 0.745 grams of water (H2O). To find the percent yield, first we need to calculate the theoretical yield based on the stoichiometry of the reaction; then we compare the actual yield (0.745 grams) to the theoretical yield. The theoretical yield is calculated using the molar mass of H2 and H2O, converting grams of H2 to moles, and then using the stoichiometry given by the balanced equation to find the moles of H2O produced. These moles are then converted back to grams. The percent yield is the (actual yield / theoretical yield) x 100%. The stoichiometry of 4H2O to 4H2 implies a 1:1 mole ratio. Using the molar mass of H2 (approximately 2.02 g/mol) and H2O (approximately 18.015 g/mol), we can calculate the theoretical yield and then the percent yield.
A2.5 L sample of a solution of sea water has a NaCl concentration of 5.4
M. What is the new concentration of this solution if it is boiled down to a
volume of 1.0 L?
13.5 is the new concentration of this solution if it is boiled down to a
volume of 1.0 L.
Explanation:
Data given:
Initial volume of the solution of sea water = 2.5 litre
Molarity of NaCl solution M1 = 5.4 M
fInal volume = 1 litre
final molarity = ?
Assuming that no loss of NaCl from sea water took place when the sea water was boiled.
applying the formula for change in concentration as:
Minitial V initial = Mfinal X Vfinal
M final = [tex]\frac{M initial X V initial}{V final}[/tex]
Putting the values in the equation:
Mfinal = [tex]\frac{5.4 X 2.5}{1}[/tex]
M final = 13.5 M
thus it can be concluded that molarity will increase drastically when volume gets reduced from 2.5 litre to 1 litre. The solution becomes highly concentrated as water volume decreases due to evaporation.
The new concentration of a seawater solution initially at 5.4 M and 2.5 L volume, after boiling down to 1.0 L, is calculated to be 13.5 M using the principle of conservation of mass and the formula M1V1 = M2V2.
The question involves calculating the new concentration of a solution when its volume changes due to boiling. A 2.5 L sample of seawater with NaCl concentration of 5.4 M is reduced to 1.0 L after boiling. To find the new concentration, we use the principle of conservation of mass, which implies that the amount of solute (NaCl) remains constant even as the volume changes. Using the formula M1V1 = M2V2, where M1 and V1 are the initial concentration and volume, and M2 and V2 are the final concentration and volume, we can calculate the new concentration after boiling down to 1.0 L.
Initial information: M1 = 5.4 M, V1 = 2.5 L, V2 = 1.0 L.
Calculation: To find M2, rearrange the formula to M2 = (M1V1) / V2. Therefore, M2 = (5.4 M * 2.5 L) / 1.0 L = 13.5 M.
The new concentration of the NaCl solution after being boiled down to 1.0 L is 13.5 M. This demonstrates how the concentration of a solution increases as the volume decreases, provided no solute is added or removed.
How many moles of CO2 will be produced from 79.0 g of C3H8
Final answer:
To find the number of moles of CO₂ produced from 79.0 g of C₃H₈, convert the mass of C₃H₈ to moles and then use the mole ratio from the balanced combustion equation to find the moles of CO₂produced, which is approximately 5.37 moles.
Explanation:
To calculate the number of moles of CO₂ produced from 79.0 g of C₃H₈ (propane), you need the balanced chemical equation for the combustion of propane, which is:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
According to this equation, one mole of propane produces three moles of CO₂. First, we need to determine the number of moles of C₃H₈ present in 79.0 g. The molar mass of propane (C₃H₈) is 44.1 g/mol.
To find the moles of propane, we use the formula:
moles of propane = mass (g) / molar mass (g/mol)
moles of propane = 79.0 g / 44.1 g/mol ≈ 1.79 mol
Now, to find the moles of CO₂ produced from the combustion of 1.79 mol of propane:
moles of CO₂ = moles of C3H8 x (3 moles CO₂ / 1 mole C₃H₈)
moles of CO₂= 1.79 mol x 3 ≈ 5.37 mol
Therefore, the combustion of 79.0 g of C₃H₈ will produce approximately 5.37 moles of CO₂.
hi:) i need help with q17. Thanks in advance:)
Answer:
Q17. D
Explanation:
A single line between 2 atoms represent a single covalent bond between a pair of electrons. There are 17 lines in the diagram hence there are 17 bonding pairs of electrons in the molecule.
Do count the double bond as 2 bonding pairs of electrons.
__1__ was used as an indicator because it is colorless in __2__ solutions and pink in __3__ solutions.
ANSWER:
1.) phenolphthalein
2.) neutral and acidic
3.) basic
Answer:
1.) phenolphthalein
2.) neutral and acidic
3.) basic
Explanation:
Answer: Phenolphthalein was used as an indicator because it is colorless in neutral and acidic solutions and pink in basic solutions.
Explanation:
Recall that in the lab we added enough of the base NaOH so that the indicator turned pink. Prior to the solution turning pink, the solution was acidic (HCl) → neutral. Furthermore, phenolphthalein is used as an indicator of basic solutions.
The equivalence/equilibrium point occurs at ph 7.
Phenolphthalein causes solutions to become pink around pH 8.2 (a basic pH). Therefore, we added slightly more NaOH than actually needed to neutralize the acid.