Answer:
The time it takes for the radioactivity of a specific isotope to fall to half its original value
Explanation:
The half time is the time it takes for the radioactivity of a specific isotope to fall to half its original value.
What is half-life?In terms of radioactivity, it is the interval of time that should be needed for one half of the atomic nuclei with respect to the radioactive sample for decaying or here the time interval should be needed for the no of disintegrations per second of a radioactive
Therefore, based on the above explanation, the third option is correct.
And, the rest of the options are wrong.
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10-kg of R-134a at 300 kPa fills a rigid container whose volume is 14 L. Determine the temperature and total enthalpy in the container. The container is now heated until the pressure is 600 kPa. Determine the temperature and total enthalpy when the heating is completed.
Answer:
Temperature = 0.605°C
Total enthalpy at 300kpa = 545.2 kJ
Total enthalpy at 600kpa = 846.45 kJ.
Explanation:
Checking the table for 134a pressure table. It is given that the specific volume of saturated liquid and the specific volume of the saturated vapor of 280kpa is 0.0007699 m^3/kg and 0.072352 m^3/kg respectively.
Also, the specific volume of saturated liquid and the specific volume of the saturated vapor of 320kpa is 0.0007772 m^3/kg and 0.063604 m^3/kg respectively.
The first thing to do is to determine the value for the specific volume of saturated liquid.
At 300 kpa, the specific volume of saturated liquid,n is given below as;
300 - 280/ 320 - 280 = (n - 0.0007699)/ 0.0007772 - 0.0007699.
Therefore, n = specific volume of saturated liquid = 0.0007735 m^3/kg.
300 - 280/ 320 - 280 = n - 0.072352/ (0.063604 - 0.072352).
n = 0.0679 m^3/kg.
The second thing to do is to determine the value of the specific volume.
Specific volume = 14 × 10^-3/ 10 = 0.0014 m^3/kg.
Determine the enthalpy of the mixture,b(I). This is given below as;
300 - 280/ 320 - 280 = b(I) - 199.54/ (196.7 - 199.54).
b(I) = 198.125 kJ/Kg.
Hence, b = [ 300 - 280/ 320 - 280 = j - 50.18 / 55.16 - 50.18] + [ ( 0.0014 - 0.00077735) / 0.067978 - 0.00077735] × 198.125.
b = 54.517 KJ/Kg.
Total enthalpy = 10 × 54.517 = 545.17 kJ.
Temperature can be Determine as below;
300 - 280/ 320 - 280 = T + 1.25 / 2.46 - 1.25.
Temperature = 0.605°C.
Hence, at 600kpa, the total enthalpy = [81.51 + ( 0.0014 - 0.0008199/ 0.034295 - 0.0008199) × 180.90] × 10
Total enthalpy at 600kpa = 846.45 kJ.
How many moles of "02" are in a 192g sample of O2? *
1
2
3
4
5
6
7
Answer: The number of moles of [tex]O_2[/tex] are 6.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]
Given mass = 192 g
Molar mass = 32 g/mol
[tex]\text{Number of moles}=\frac{192g}{32g/mol}=6mol[/tex]
The number of moles of [tex]O_2[/tex] are 6.
What is the molarity of a solution made from 325.4g of Aluminum chloride with enough water te
make 500.0 mL?*
(1 Point)
AICIAl = 26.9828 C1 = 35.45
mol
8
mol
0.488M
O 4.88M
0 2.44M
0 2.440M
Answer:
awdaef
Explanation:
Just like cans of soup, atoms of the same element often have different masses. These different varieties are called isotopes. In the Average Atomic Mass Gizmo, you will learn how to find the average mass of an element using an instrument called a mass s
Answer:
ions are deflected and the lighter the ions the more the deflection.
Placing magnetic field in the path of the ions cause them to move in a curved path.
Explanation:
This question is all about the way in which mass spectroscopy works. Mass spectroscopy Is one of the techniques in spectroscopy which is used in the identification of chemical compounds.
Mass spectroscopy works based on the principle of ionization. For a mass spectroscopy to start ionization must first occur that is to say this is the first step in the identification of compound in mass spectroscopy.
The following steps are involve in mass spectroscopy;
=> Ionization: the molecules of the sample are first ionized. The ions formed here are positive ions.
=> Acceleration: the ions in step one are accelerated.
=> Deflection: the smaller ions get deflected more than the bigger ions. The magnetic field is used in the deflection of this ions.
=> Detection: the ions are then detected.
Therefore, to answer the question, the ions are deflected and the lighter the ions the more the deflection.
Placing magnetic field in the path of the ions cause them to move in a curved path.
3. You can express the density of an object in units of kg/L or in units of
g/mL. How is the density of an object in kg/L related to its density in g/mL?
Can some one help I'm lost iam being timed:( Show using two conversion factors how you would convert from 0.020 kg into mg
Answer:
20000 Mg
Explanation:
What group of elements on the periodic table is not usually found in nature?
Answer:
Halogens
Explanation:
they they are never found free in nature.
Can someone help with these questions please???
How many significant figures are in the following measurement? 433.8 liters
what process formed slate
Answer:
Explanation:
Slate is a fine-grained, foliated metamorphic rock that is created by the alteration of shale or mudstone by low-grade regional metamorphism. It is popular for a wide variety of uses such as roofing, flooring, and flagging because of its durability and attractive appearance.
Answer:
Deep within the Earth's crust rocks can be put under huge pressures and temperatures are very high. These conditions can cause the minerals in the rock to change. This process is called metamorphism. Limestone can change into marble, shale and mudstones into slate, and igneous rocks like granite can turn into gneiss.
Explanation:
Slate is a fine-grained, foliated metamorphic rock that is created by the alteration of shale or mudstone by low-grade regional metamorphism. It is popular for a wide variety of uses such as roofing, flooring, and flagging because of its durability and attractive appearance.
list 5 island in the Philippines
Answer:
Coron, Palawan, El Nido, Palawan, Cebu, Boracay, Siargao.
Explanation:
I hope this helps.
coron,palawan,El nidu, Cebu and boracay are 5 island in Philippines.....
How many O atoms are in 7.39 g CO2?
Answer:
2 O atoms
hope it helps....
Answer:
2O is the correct answer
A continuously stirred tank reactor is designed to remove the hazardous waste compound trichloroethylene (TCE) from industrial wastewater. The tank is 3250 liters. The wastewater flows into the tank at 200 L/min with a TCE concentration of 25 mg/L. The reactor decays TCE at a reaction rate of 0.20 min-1 . What is the steady-state concentration of TCE in the treated water leaving the reactor
Answer:
the steady-state concentration of TCE in the treated water leaving the reactor is 5.88 mg/L
Explanation:
Given that;
Tank volume v = 3250 liters
wastewater flows into the tank Q = 200 L/min
TCE concentration Co= 25 mg/L
reactor decays TCE at a reaction rate K = 0.20 min-1
mass balance
we know that;
Accumulation = inflow - outflow ± generation
⇒dc/dt = QCo - Qc ± rc.V
now at a steady state; dc/dt = 0
so
0 = QCo - Qc + rcV
where rc = -kc
0 = QCo - Qc - kcV
Qc + kcV = QCo
c(Q + kV) = QCo
c = QCo / (Q + kV)
so we substitute
c = (200 × 25) / (200 + (0.2×3250))
c = 5000 / 850
c = 5.88 mg/L
Therefore, the steady-state concentration of TCE in the treated water leaving the reactor is 5.88 mg/L
A bullet seized from a crime scene has a composition of lead 11.6 g, tin 0.5 g, and
antimony 0.4 g. What is the percentage of lead in the bullet? Express your answers to
the ones place.
Answer:
92.8%
Explanation:
Step 1: Given data
Mass of lead in the bullet (mPb): 11.6 gMass of tin in the bullet (mSn): 0.5 gMass of antimony in the bullet (mSb): 0.4 gStep 2: Calculate the total mass of the bullet
The total mass of the bullet is equal to the sum of the masses of the elements that form it.
m = mPb + mSn + mSb = 11.6 g + 0.5 g + 0.4 g = 12.5 g
Step 3: Calculate the mass percentage of Pb in the bullet
We will use the following expression.
%Pb = mPb / m × 100%
%Pb = 11.6 g / 12.5 g × 100% = 92.8%
tell me how is your life as a youngster
Answer:
ruthless, my style as a juvenile
ran with a gang, slanged in the meanwhile
Explanation:
What happens when a base dissolves?
A. It increases the concentration of OH in solution.
B. It increases the concentration of H+ in solution.
C. It adds oxygen to the solution.
D. It is no longer dangerous.
Answer:
A. It increase the concentration of OH in solutions.
Explanation:
Bases are substances that react with and neutralise acids, producing water. When dissolved, bases release hydroxide ions, OH-(aq) into solution.
When a base dissolves, it increases the concentration of OH⁻ ions in the solution. Therefore, option A is correct.
What are acids and bases?An acid can be described as a substance that is capable of donating a hydrogen ion to another substance. A base can be described as a molecule or ion that is able to have a hydrogen ion from an acid.
Acidic materials are commonly identified by sour taste. An acid can be considered commonly a molecule that can donate an H⁺ ion and can be energetically favorable after a loss of H⁺ ion. Acids increase the concentration of H⁺ ions in solution.
Bases are described by a bitter taste and a slippery nature. A base or alkali increases the concentration of OH⁻ ions in the solution. When bases react with acids, they give salts and water as products.
The pH range on the pH scale of the acids lies between 0 to 7 and the pH range of the bases lies between 7 to 14.
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Calculate the number of Li atoms in 7.8 mol of Li.
Express your answer using two significant figures.
4.7 × 10²⁴ atoms Li
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
7.8 mol Li
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
Set up: [tex]\displaystyle 7.8 \ mol \ Li(\frac{6.022 \cdot 10^{23} \ atoms \ Li}{1 \ mol \ Li})[/tex]Multiply/Divide: [tex]\displaystyle 4.69716 \cdot 10^{24} \ atoms \ Li[/tex]Step 4: Check
We are told to round to 2 sig figs. Follow sig fig rules and round.
4.69716 × 10²⁴ atoms Li ≈ 4.7 × 10²⁴ atoms Li
Calcium and titanium atoms have the same mass
Answer:
these elements do not have the same masses.
CH3CH3C(CH3)2CH2I classification and name
Answer:
1,2 di methyl 5 ene tri chloro hexane
How many grams of silver nitrate are needed to prepare 0.125 M solution in 250.0 mL of water?*
(1 Point)
AgNO₃
Ag
= 107.868 8
mol
N = 14.0078
mol
8
0 = 15.999
mol
0.313 g
169.872 g
0.0849 g
5.31 g
O 31.3 g
Answer:5.3 grams AgNO3
Explanation:
To solve your problem, take a look at the definition of molality (m):
moles of solute/kg of solvent
You are given the grams of solvent (water) to find the grams of silver nitrate.
First, convert 250 grams to kg:
250 g * 1 kg / 1000g = 0.250 kg
Now that you have the kg of solvent, you can solve for the moles of solute:
kg of solvent * molality = moles of solute
0.250 kg * 0.125 m = 0.03125 mol AgNO3
You can convert the number of moles to grams using the molar mass of AgNO3, which is 169.872 g/mol:
moles of solute * molar mass of solute = grams of solute
0.03125 mol AgNO3 * 169.872 g/mol = 5.3085 g
Because your question provides two significant digits, you must round this number to get the final answer:
5.3 grams AgNO3
I hope this helps!
Richard sketched models of two different neutral isotopes of oxygen. If the
isotope models are accurate, which statement might be true? (Refer to the
periodic table if necessary.)
A. One shows 7 protons, and one shows 9.
B. One shows 8 neutrons, and one shows 9.
C. One shows 8 electrons, and one shows 9.
D. One shows 8 protons, and one shows 7.
Answer:
its b
Explanation:
just did the test on A P E X
If the isotope models are accurate, One shows 8 neutrons, and one shows 9. Therefore, the correct option is option B.
What is isotope?A chemical element's isotope is one of more than one species of atoms that share the same atomic number, spot on the periodic table, and almost identical chemical activity, but differ in atomic mass and physical characteristics. There are a number of isotopes for each chemical element.
The first step in identifying and labelling an atom is to count the protons within its nucleus. Usually, this nuclear number is denoted by the letter Z. The fact that all atoms possessing the same number of electrons have essentially equal chemical characteristics lends the atomic number its enormous significance. If the isotope models are accurate, One shows 8 neutrons, and one shows 9.
Therefore, the correct option is option B. If the isotope models are accurate, One shows 8 neutrons, and one shows 9.
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How many formula units of CuCl2 are present in 18.42 g?
Answer:
Think 12 units
Explanation:
Because it represents the hands of the clock
what is its molar concentration?
Answer:
The correct answer is - the number of moles of solute per liter of solution.
Explanation:
The molar concentration is also known as molarity which is the amount of concentration of a solute is in a chemical solution is the number of moles of solute per unit volume of solution. It is represented as M and can be calculated by:
M = n/v
Where n is the number of moles of the solute and,
v is the volume of solution (in liters normally)
It is worldwide used measurment for the concentration.
An unknown compound contains only C , H , and O . Combustion of 5.90 g of this compound produced 11.8 g CO2 and 4.83 g H2O . What is the empirical formula of the unknown compound
Answer:
C₂H₄O
Explanation:
In a compound that contains Cabon, hydrogen and oxygen, the combustion produce CO₂ from the carbon, and H₂O from the hydrogens. Using the mass of the products we can solve the moles of Carbon and hydrogen. The empirical formula is the simplest whole-number of atoms present in a molecule.
Moles CO₂ = Moles C:
11.8g CO₂ * (1mol / 44g) = 0.268 moles CO₂ = 0.268 moles C * (12g/mol) =
3.216g C
Moles H₂O = 1/2 moles H:
4.83g H₂O * (1mol / 18g) = 0.268 moles H₂O * (2 mol H / 1 mol H₂O) =
0.537 mol H * (1g/mol) = 0.537g H
Mass O to find moles O:
5.90g Sample - 3.216g C - 0.537g H = 2.147g O * (1mol / 16g) = 0.134 moles O
Ratio of atoms -Dividing in 0.134 moles-:
C = 0.268mol C / 0.134 mol O = 2
H = 0.537mol H / 0.134 mol O = 4
O = 0.134mol O / 0.134 mol O = 1
Empirical formula is:
C₂H₄OEquipment used for solar energy is usually not expensive.
True False
Answer:
False, hope this helps!
Explanation:
Determine the mass of AgCl(s) produced when 0.91 g of AgNO3 in an aqueous solution reacts with excess NaCl aqueous solution as shown below: AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq) i Respond with the correct number of significant figures in scientific notation (Use E notation and only 1 digit before decimal e.g. 2.5E5 for 2.5 x 10")
Answer:
0.77 g
Explanation:
Step 1: Write the balanced equation
AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)
Step 2: Calculate the moles corresponding to 0.91 g of AgNO₃
The molar mass of AgNO₃ is 169.87 g/mol.
0.91 g × 1 mol/169.87 g = 5.4 × 10⁻³ mol
Step 3: Calculate the moles of AgCl produced from 5.4 × 10⁻³ moles of AgNO₃
The molar ratio of AgNO₃ to AgCl is 1:1. The moles of AgCl produced are 1/1 × 5.4 × 10⁻³ mol = 5.4 × 10⁻³ mol.
Step 4: Calculate the mass corresponding to 5.4 × 10⁻³ moles of AgCl
The molar mass of AgCl is 143.32 g/mol.
5.4 × 10⁻³ mol × 143.32 g/mol = 0.77 g
Surface tension is a force that affects....
A. Gases
B. Plasmas
C. Solids
D. Liquids
Answer:
option A iis the right answer
1. How would you describe what red cabbage juice is?*
(1 Point)
Acid
Neutral
Alkali
Indicator
Salt
Iron melts at 1535 °C. What would this temperature be in Fahrenheit
Answer:
2,795 F
Explanation:
Why does adding lemon juice to a blueberry smoothie
make it change color from purple to pink.
Answer:
Acidity
Explanation: