Answer:
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Explanation:
Scientists who are investigating what has happened over the years to the people who were exposed to radiation during the 1986 Chernobyl nuclear disaster are conducting what type of study
Answer:
Observational study
Explanation:
An investigation of what happened over the years to the people who were exposed to radiation during the 1986 Chernobyl nuclear disaster would be termed an observational study because it will require observing subjects and finding out if there is a kind of correlating factor in the subjects that could indicate the level of exposure to the nuclear radiation.
There are basically two types of research studies:
1. Observational studies
2. Experimental studies
Observational studies involve just the observation of subjects and trying to find out some correlation factors. This kind of study could be prospective when it deals with what could happen in the future based on certain factors or retrospective when it considers what has already happened. An observational study can be cross-sectional, case-only, case-control, or cohort study.
Experimental studies are also referred to as randomized or controlled trial studies. Here, subjects are grouped and each group receives a different treatment in order to isolate the effect of a particular factor or variable relating to the treatment.
Given the following balanced equation, determine the rate of reaction with respect to [Cl2]. If the rate of Cl2 loss is 4.64 × 10-2 M/s, what is the rate of formation of NOCl? 2 NO(g) + Cl2(g) → 2 NOCl(g)
Answer:
[tex]r_{NOCl}=9.28x10^{-2}M[/tex]
Explanation:
Hello!
In this case, given the balanced chemical reaction:
[tex]2 NO(g) + Cl_2(g) \rightarrow 2 NOCl(g)[/tex]
Since there is 1:2 mole ratio between chlorine and NOCl, based on the rate proportions, we can write:
[tex]\frac{1}{-1}r_{Cl_2} =\frac{1}{2}r_{NOCl}[/tex]
It means that for the formation of NOCl, we obtain:
[tex]r_{NOCl}=\frac{2}{-1}r_{Cl_2} \\\\r_{NOCl}=\frac{2}{-1}(-4.64x10^{-2}M)\\\\r_{NOCl}=9.28x10^{-2}M[/tex]
Notice that chlorine is disappearing, which means its rate is negate.
Best regards!
What are things animals might do to survive?
Answer:
Animals need food, water, shelter, and space to survive. Herbivores can live only where plant food is available. Carnivores can live only where they can catch their food. Omnivores can live in many places because they eat both plants and animals.
Describe the potential energy of a chemical reaction and how the energy is accessed?
Explanation:
The energy released due to breakage of bond or we can say that protons and electrons go from a structure of higher potential energy to lower potential energy. During this change, potential energy is converted to kinetic energy in form of heat.
Generally chemical potential energy is accessed in form heat, which the difference between the potential energies of reactant and product.
How do you know your cell's are working
Suppose the current flowing from a battery is used to electroplate an object with silver. Calculate the mass of silver that would be deposited by a battery that delivers 1.65 A·hr of charge.
Answer:
m = 0.00659 kg = 6.59 g
Explanation:
From Faraday's Law of Electrolysis, we know that:
m = ZQ
where,
m = mass of silver deposited = ?
Q = charge supplied = (1.65 A-hr)(3600 s/1 hr) = 5940 C
Z = electrochemical equivalent of silver = 1.18 x 10⁻⁶ kg/C
Therefore,
m = (1.11 x 10⁻⁶ kg/C)(5940 C)
m = 0.00659 kg = 6.59 g
The mass of silver that would be deposited by a battery is 6.65 grams
The precipitation of Ag requires the removal of one electron. The reduction process for silver electrode at the cathode is as follows:
[tex]\mathbf{Ag^+ + e^- \to Ag(s)}[/tex]
The current flowing in the battery = 1.65 A = 1.65 C/sThe time at which the current is flowing = 1 hr = 3600sec∴
The charge Q = Current (I) × time (t)Charge Q = 1.65 C/s × 3600 sCharge (Q) = 5940 CIn one mole of an electron, the charge carried = 96500 C
Recall that:
The atomic mass of silver (Ag) = 108 g
∴
The mass of silver that would be deposited in a 5940 C can be computed as:
[tex]\mathbf{=5940\ C \times \dfrac{108 \ g }{96500 \ C}}[/tex]
= 6.65 grams
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A graduated cylinder initially has 32.5 mL of water in it. After a 75.0 g piece of lead (Pb) is added to the graduated cylinder, the water level rises to the 39.1 mL mark. What is the the volume of the piece of lead.
Answer:
39.1-32.5 and you will find your answer it always like that, you subtract your starting point from your ending point
Explanation:
The volume of the piece of lead is 6.6 mL
From the question given above, the following data were obtained:
Volume of water = 32.5 mLMass of lead (Pb) = 75 gVolume of water + Lead = 39.1 mLVolume of lead =?The volume of the lead can be obtained as follow:
Volume of lead = (Volume of water + Lead) – (Volume of water)
Volume of lead = 39.1 – 32.5
Volume of lead = 6.6 mL
Therefore the volume of the lead is 6.6 mL
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A container holds 3.41×10−3mol of carbon dioxide (CO2). After the addition of 8.41×10−4mol of carbon dioxide, the volume of the container increases to 95.2mL, with the temperature and pressure remaining constant. What was the initial volume of the container?
Answer:
76.366
Explanation:
Knewton answer is 76.4
Answer:
76.4mL
Explanation:
First, calculate the final number of moles of carbon dioxide (n2) in the container.
n2 = n1+n added = 3.41×(10^-3) mol+8.41×(10^-4) mol = 4.25×(10^-3) mol
Rearrange Avogadro's law to solve for V1.
V1 =(V2×n1)/n2
Substitute in the known values for n1, V2, and n2.
V1 = (95.2mL×(3.41×10^-3 mol))/(4.25×(10^-3) mol)=76.4mL
So the initial volume is 76.4mL.
The closer to 7 a substance measures on the pH scale, the ______ the compound fill in the blank
Explanation:
If the PH is greater than 7 then the solution is basicIf the PH is less than 7 then the solution is acidicIf the PH is equal to 7 then the solution is neutralWhich of these mixtures would NOT be separated by using simple distillation?
Ink and water
Salt and water
Sand and water
There is a golden role of solubility, polar solute dissolve in polar solvent and non polar solute dissolve in non polar solvent. Therefore, the correct option is option B that is Salt and water.
What is solution?Solutions are a homogeneous mixture of two or more substances. A solution is a homogeneous mixture of solvent and solute molecules. Solvent is a substance that is in large amount in solution. solute is the substance which is in small amount in a solution. There are two types of mixture that is homogeneous and heterogeneous. Solution is a homogeneous solution.
Salt and water because salt is transparent and will dissolve into the water among given solute, salt NaCl is a polar solute which will dissolve in polar solvent that is water.
Therefore, the correct option is option B that is Salt and water.
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A 13.8 g of zinc is heated to 98.8 c in boiling water and then dropped onto a beaker containing 45.0 g of water at 25.o °C .when the water and metal come to thermal equilibrium the temperature is 27.1°C .what is the specific heat capacity
Answer:
[tex]C_{zinc}=0.400\frac{J}{g\°C}[/tex]
Explanation:
Hello!
In this case, by considering thermodynamics and the temperature of zinc, we can infer it is hot while water is cold, it means that the heat lost by the zinc is gained by the water and we can write:
[tex]Q_{Zn}=-Q_{water}[/tex]
In terms of mass, specific heat and temperatures we can write:
[tex]m_{Zn}C_{Zn}(T_{eq}-T_{Zn})=-m_{water}C_{water}(T_{eq}-T_{water})[/tex]
In such a way, by solving for the specific heat capacity of the zinc we write:
[tex]C_{zinc}=\frac{-m_{water}C_{water}(T_{eq}-T_{water})}{m_{Zn}(T_{eq}-T_{Zn})}[/tex]
Thus, by plugging in the given values we obtain:
[tex]C_{zinc}=\frac{-45.0g*4.184\frac{J}{g\°C}* (27.1\°C-98.8\°C)}{13.8g*(27.1\°C-98.8\°C)}\\\\C_{zinc}=0.400\frac{J}{g\°C}[/tex]
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Find the pH of the equivalence point and the volume(ml) of 0.125M HCl needed to reach the point in titrations of: a) 65.5ml of 0.234M NH3.b) 21.8 mL of 1.11 M CH3NH2.
Answer:
a. 122.6 mL / pH = 4.03
b. 193.6 mL / pH = 5.73
Explanation:
In the equivalence point we know: mmoles acid = mmoles base- And the pH in a titration between a weak base and a strong base, is acid, at the equivalence point. For the volume, we can replace the equation with the data given.
a. 0.125M . volume of acid = 65.5 mL . 0.234M
Volume of acid = (65.5 . 0.234) / 0.125 = 122.6 mL
Total volume at the equivalence point = 188.1 mL
b. 0.125M . volume of acid = 21.8 mL . 1.11 M
Volume of acid = (21.8 . 1.11) / 0.125 = 193.6 mL
Let's calculate the pH. In the equilavence point we have a neutralization reaction.
a. NH₃ + HCl → NH₄Cl
All the mmoles of protons (65.5 mL . 0.234M) react to ammonia, to obtain ammonium.
New concentration is: 15.32 mmoles / 188.1 mL = 0.0814 M
This is the [NH₄⁺] to determine the pH in the acid base equilibrium.
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
Expression for Ka = [NH₃] . [H₃O⁺] / [NH₄⁺]
5.6×10⁻¹⁰ = x² / (15.32 - x)
(We can avoid the quadratic equation 'cause Ka is so small)
√(5.6×10⁻¹⁰ . 15.32) = x → [H₃O⁺] = 9.26×10⁻⁵
pH = - log [H₃O⁺] → 4.03
b. CH₃NH₂ + HCl → CH₃NH₃Cl
All the mmoles of protons (21.8 mL . 1.11M) react to methylamine, to obtain methylammonium.
New concentration is: 24.2 mmoles / 193.6 mL = 0.125 M
This is the [CH₃NH₃⁺] to determine the pH in the acid base equilibrium.
CH₃NH₃⁺ + H₂O ⇄ CH₃NH₂ + H₃O⁺ Ka
Expression for Ka = [CH₃NH₂] . [H₃O⁺] / [CH₃NH₃⁺]
2.7×10⁻¹¹ = x² / (0.125 - x)
(We can avoid the quadratic equation 'cause Ka is so small)
√(2.7×10⁻¹¹ . 0.125) = x → [H₃O⁺] = 1.84×10⁻⁶
pH = - log [H₃O⁺] → 5.73
The pH of the equivalence point of 0.125M HCl with NH₃ is 4.03 and with CH₃NH₂ is 5.73.
What is equivalence point?In the acid - base titration, at the equivalence point equal moles of acid as well as of base are present.
First we calculate the volume of HCl by using the below equation as:
M₁V₁ = M₂V₂, whereM₁ = molarity of NH₃ = 0.234 M
V₁ = volume of NH₃ = 65.5 mL
M₂ = molarity of HCl = 0.125 M
V₂ = volume of HCl = ?
V₂ = (65.5 . 0.234) / 0.125 = 122.6 mL
Total volume at the equivalence point = 188.1 mL
Chemical reacion will be written as:
NH₃ + HCl → NH₄Cl
All moles of protons react with moles of ammonia, so new moles (n) will be calculated as:
n = molarity × volume
n = 65.5 mL × 0.234M = 15.32 moles
Now, concentration in terms of molarity will be 15.32 mmoles / 188.1 mL = 0.0814 M
pH in the acid-base reaction due to [NH₄⁺], as:
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺
Value of Ka for this reaction is = 5.6×10⁻¹⁰
According to the ICE table, Ka equation will be written as-
5.6×10⁻¹⁰ = x² / (15.32 - x)
x = [H₃O⁺] = 9.26 × 10⁻⁵
pH = - log [H₃O⁺] = 4.03
Again we calculate the volume of HCl with the CH₃NH₂ as:0.125M . volume of acid = 21.8 mL . 1.11 M
Volume of acid = (21.8 . 1.11) / 0.125 = 193.6 mL
Total volume at the equivalence point = 215.4 mL
Chemical reacion will be written as:
CH₃NH₂ + HCl → CH₃NH₃Cl
All moles of protons react with moles of ammonia, so new moles (n) will be calculated as:
n = 21.8 mL . 1.11M = 24.2 moles
Now, concentration in terms of molarity will be 24.2 moles / 215.4 mL = 0.11M
pH in the acid-base reaction due to [CH₃NH₃⁺], as:
CH₃NH₃⁺ + H₂O ⇄ CH₃NH₂ + H₃O⁺
Value of Ka = 2.7×10⁻¹¹
According to the ICE table, Ka equation will be written as-
2.7×10⁻¹¹ = x² / (0.11 - x)
x = [H₃O⁺] = 5.4×10⁻⁶
pH = - log [H₃O⁺] = 5.73
Hence the value of pH will be 4.03 and 5.73 respectively.
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Robert was changing the oil in his truck. He dumped the used oil on the ground in his yard. He didn't know it, but Robert was hurting the environment because the oil-
HELP FAST
Answer:
goes deep into the ground and pollutes the groundwater.
BaO2 is a peroxide. Why?
Answer:
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A 2kg metal cylinder is supplied with 1600J of energy to heat it from 5*C to 13*C. What is the SHC of the metal?
Answer:
100Jkg/°C
Explanation:
Given parameters:
Mass of metal = 2kg
Amount of heat energy = 1600J
Initial temperature = 5°C
Final temperature = 13°C
Unknown:
Specific heat capacity of the metal = ?
Solution:
Specific heat capacity of a body is the amount of heat needed to raise the temperature of unit mass of a body by 1°C.
H = m x C x (T₂ - T₁ )
H is the amount of heat
m is the mass
C is the unknown specific heat capacity
T is the temperature
Insert the parameters and solve;
1600 = 2 x C x (13 - 5)
1600 = 16C
C = 100Jkg/°C
what is the mass of 16.6 x 10^23 molecules of barium nitrate
The mass of 16.6 × 10²³ molecules of barium nitrate is 718.7g
The number of moles of a substance can be calculated by dividing the mass by its molar mass. That is;no. of moles = mass(g) ÷ molar mass (g/mol)no. of moles of Ba(NO3)2 = 16.6 × 10²³ ÷ 6.02 × 10²³no. of moles = 2.75 × 10⁰no. of moles = 2.75moles. Molar mass of Ba(NO3)2 = 261.34g/molmass of Ba(NO3)2 = 261.34 × 2.75Mass of Ba(NO3)2 = 718.7gTherefore, the mass of 16.6 × 10²³ molecules of barium nitrate is 718.7g.Learn more at: https://brainly.com/question/15743584?referrer=searchResults
12. When the frequency of a wave increases, what happens to the wavelength?
A. The wavelength is not directly affected by the frequency of a wave
B. The wavelength increases
C. The wavelength decreases
D. More specific information is needed to form a conclusion
Answer:
C. The wavelength decreases
Explanation:
This is because frequency is how often the wave hits the top (peak) and the bottom (through). The more it hits the less wavelength it will have because it is moving faster and has more energy.
How can energy from the Sun be used to heat water? What
things will affect how well the sunlight heats water?
Answer:
Water is heated as it travels through flat, glazed panels known as solar collectors, which are normally situated on the roof of the building. The heated water is then stored in an insulated storage tank.
what is the number of each element and the total number of atoms for vinegar?
Which statement describes how phase changes can be diagrammed as a substance is heated?
The phase is on the y-axis and the temperature is on the x-axis.
The temperature is on the y-axis and the phase is on the x-axis.
The time is on the y-axis and the temperature is on the x-axis.
The temperature is on the y-axis and the time is on the x-axis.
Answer:
The temperature is on the y-axis and the time is on the x-axis.
Explanation:
Which statement describes how phase changes can be diagrammed as a substance is heated? (D is the answer)
The phase is on the y-axis and the temperature is on the x-axis.
The temperature is on the y-axis and the phase is on the x-axis.
The time is on the y-axis and the temperature is on the x-axis.
The temperature is on the y-axis and the time is on the x-axis.
Which statement describes the appearance of a temperature-vs.-time graph? (C is the answer)
A horizontal line shows that the temperature increases at a constant rate over time.
A vertical line shows that the temperature decreases at a constant rate over time.
Horizontal lines where the temperature is constant during phase changes connect upward-sloping lines where the temperature increases.
Horizontal lines where the temperature increases are connected by upward-sloping lines where the temperature is constant for each phase.
how fast is a formula 1 car? (For my chemistry project)
Answer:
it's 200 mph fast........
which have
different numbers of electrons?
Answer:
These are called isotopes. They have the same number of protons (and electrons), but different numbers of neutrons. Different isotopes of the same element have different masses. Mass is the word for how much substance (or matter) something has.
of the element listed wich
has the largest atomic rodius?
Calcium Cas Copper (ca)
Chromium (Cr)
Cobalt (co)
The atomic radius trend on the Periodic Table is as follows:
- Atomic radius increases down a column (or group)
- Atomic radius decreases across rows (or periods) from left to right
Looking at my Periodic Table, calcium, chromium, cobalt and copper are in that order from left to right in the same period, which simplifies things significantly.
Since these elements are in the same period, and given that we know atomic radius decreases across periods from left to right, we can see that calcium has the largest atomic radius.
Identify the place which has the highest boiling point of water. Identify the place which has the highest boiling point of water. Denver, Colorado, 5280 feet Death Valley, 282 feet below sea level New Orleans, sea level Mt. Everest, 29035 feet A pressurized passenger jet, 35,000 feet
Answer:
B. because if it was to change so would the amount of wieght that gravity puts on us.
Explanation:
A. might seem right but it's not 35,000 under seal level is the OPPOSITE of 35,000 above sea level.
C. water pressure can change where you are at because of the speed or the type of body of water.
D. it does not make any sense.
hope this helps!!!
The chemical reaction between iron (Fe) and oxygen (O) results in the loss of electrons from iron. This reaction is an example of _____.
A) respiration
B) sublimation
C) oxidation
D) combustion
Answer:
d combustion because iron and oxegen need eachother
Answer:
The Correct answer would be Oxidation.
Explanation:
What are five minerals found on space rocks
Answer:
oxygen, silicon, iron, calcium, sodium
Explanation:
these are all found in space rocks known as meteorites. hope this helps :)
1. A baseball pitcher won 75% of the games he pitched. If he pitched 43 ballgames, how many games
did he win?
Answer:
He won 32 games.
Explanation:
Another way of expressing 75% is 75/100.
To calculate how many games the baseball pitcher won, we multiply the total of games played (43, in this case) by the percent won:
43 * 75/100 = 32.25 ≅ 32
So the baseball pitcher won 32 games.
How many Stars are In the Milky way Galaxy
Answer:
100 thousand million stars
Explanation:
Answer:
100 to 400 billion stars
Oxygen gas is made of molecules like the one this model shows. Which
chemical formula most likely describes oxygen gas?
A. OG
B. 00
C. 02
D. 0100
A mixture of neon and xenon gases, at a total pressure of 739 mm Hg, contains 0.919 grams of neon and 19.1 grams of xenon. What is the partial pressure of each gas in the mixture?_______g Xe
Answer:
Partial pressure of neon = 175 mmHg
Partial pressure of xenon = 564 mmHg
Explanation:
The partial pressure of a gas in a mixture can be calculated as the product of the mole fraction of the gas (Xi) and the total pressure (Pt), as follows:
Pi = Xi Pt
The total pressure is 739 mmHg ⇒ Pt = 739 mmHg
In order to calculate the mole fraction of each gas, we have to first calculate the number of moles of each gas (n) by dividing the mass of the gas into the molar mass (MM):
For neon gas (Ne):
MM(Ne) = 20.18 g/mol
n(Ne)= mass/MM = 0.919 g x 1 mol/20.18 g = 0.045 mol Ne
For xenon gas (Xe):
MM(Xe) = 131.3 g/mol
n(Xe)= mass/MM = 19.1 g x 1 mol/131.3 g = 0.145 mol Xe
Now, we calculate the mole fraction (X) by dividing the number of moles of the gas into the total number of moles (nt):
nt= moles Ne + moles Xe = 0.045 mol + 0.145 mol = 0.190 mol
X(Ne) = moles Ne/nt = 0.045 mol/0.190 mol = 0.237
X(Xe) = moles Xe/nt = 0.145/0.190 mol = 0.763
Finally, we calculate the partial pressures of Ne and Xe as follows:
P(Ne) = X(Ne) x Pt = 0.237 x 739 mmHg = 175 mmHg
P(Xe) = X(Xe) x Pt = 0.763 x 739 mmHg = 564 mmHg