Answer:
2000 years
Explanation:
A radioactive molecule will continuously decay and turn into another molecule. This nature of the radioactive molecule makes them can be used to estimate the age of an object. Half-life is the unit of time needed for radioactive molecules to decay to half of its mass. The formula for the mass remaining will be:
[tex]N(t)= N_{0} (\frac{1}{2})^{\frac{t}{t_{1/2} } }[/tex]
Where
N(t)= number of the molecule remains
N0= number of molecule initially
t= time elapsed
t1/2= half time
We have all variable besides the half time, the calculation will be:
[tex]N(t)= N_{0} (\frac{1}{2})^{\frac{t}{t_{1/2} } }[/tex]
[tex]0.125= 1 (\frac{1}{2})^{\frac{6000}{t_{1/2} } }[/tex]
[tex](\frac{1}{8})= (\frac{1}{2})^{\frac{6000}{t_{1/2} } }[/tex]
[tex](\frac{1}{2})^3= (\frac{1}{2})^{\frac{6000}{t_{1/2} } }[/tex]
3= 6000/ (t1/2)
t1/2= 6000/3= 2000
The half-life is 2000 years
Which statement best describes the kinetic molecular
theory?
The kinetic molecular theory relates the properties of a state of matter to the motion of
its molecules.
B
The kinetic molecular theory relates the properties of a state of matter to the mass of its
molecules.
C
The kinetic molecular theory relates the properties of a state of matter to the size of its
molecules.
D
The kinetic molecular theory relates the properties of a state of matter to the diameter of
its molecules.
The kinetic molecular theory is best illustrated by the statement that the properties of a state of matter is associated with the motion of its molecules.
Kinetic molecular theory:According to the kinetic molecular theory, all the matter is formed of particles, which are in motion spontaneously. All the particles possess energy, however, the energy changes based upon the temperature of the sample of matter. This is further determined by the fact that whether the substance prevails in liquid, solid, or gaseous state.
In the solid phase, the molecules exhibit the least amount of energy, while the particles of gas exhibits the highest amount of energy. According to the kinetic molecular theory, all the particles of gas are in spontaneous motion and exhibit perfectly elastic collisions.
Thus, the correct statement is option A.
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The kinetic molecular theory best describes the properties of a state of matter as being related to the motion of its molecules, not their mass, size, or diameter.
Explanation:The kinetic molecular theory is a model that explains the properties and behavior of matter, particularly in the state of gases. The theory posits that matter is made up of tiny particles that are always in motion. This motion is responsible for the observable properties of solids, liquids, and gases. The theory is most applicable to an ideal gas, which is a hypothetical gas that perfectly adheres to the kinetic molecular theory's assumptions, with molecules that are in constant motion, having negligible volume, colliding elastically, and with a distribution of speeds dependent on temperature.
In relation to the question, which statement best describes the kinetic molecular theory, the correct answer is:(A). The kinetic molecular theory relates the properties of a state of matter to the motion of its molecules.
is this equation balanced?
nh4oh+hc2h3o2=nh4c2h3o2+h2o
Answer:
It IS balanced
Explanation:
Answer:
Quite honestly it makes little sense, but I cannot read it as you intend.
Remember Carbon ALWAYS makes 4. Bonds, except as highly reactive species.
Explanation:
A reaction of 12.640 g of copper
oxide with 0.316 g hydrogen
produces 2.844 g of water and Xg
of copper. X=_9
Answer: it’s 10.112
Explanation:
This question relates to the law of conservation of mass in a chemical reaction. Following this law, the weight of copper (X) can be found by subtracting the weights of water and hydrogen from the weight of initial copper oxide. The calculated copper weight will be approximately 9.48g.
Explanation:This question relates to a chemical reaction which suggests you are being asked to understand the law of conservation of mass. In a chemical reaction, mass cannot be created or destroyed, only rearranged. The correct method to solve this problem is to add the mass of the water produced and the mass of copper produced and use this total to find the mass of the copper.
If we add the weight of water (2.844g) and the weight of copper (which is given to be 'X'), we will get the total weight of copper oxide, because in a reaction, the total mass of the reactants is equal to the total mass of the products. From the problem, we know that total weight of copper oxide is 12.640g. So
X = 12.640g (Copper Oxide) - 2.844g (Water) - 0.316g (Hydrogen)
When we calculate this we find that X = 9.480g.
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What does fossil mean in my own words
Answer: A thing that died a long time ago, and it's bones were preserved in the ground.
Explanation:
Because yes
Calculate the moles of NaCl in a 5 L of a 4 M NaCl solution?
Answer:
20moles
Explanation:
Molarity of a solution = moles of solute / volume of solution
Therefore
Molarity of NaCl solution = moles of NaCl ÷ volume of NaCl solution
Given,
Molarity of solution = 4M
Moles of NaCl = ?
Volume of solution = 5L
4M = moles of NaCl ÷ 5L
Multiply both sides by 5
Moles of NaCl = 4×5 moles
= 20moles
I hope this was helpful, please mark as brainliest
lewis structure for Si2H2
See Attached
Explanation:
From the neutral molecule formulae, there are two Silicon atoms and two hydrogen atoms;
Silicon has four (4) valence electrons while Hydrogen has (1) one. To achieve stable electron configuration. Silicon needs its unfilled orbital to have 8 electrons while Hydrogen needs its only orbital to have 2 electrons. The involved atoms will share electrons to form covalent bonds as shown in the Lewis dot illustration (attached). Notice the double bond between the two Silicon
Final answer:
The Lewis structure for Si2H2 includes a triple bond between the two silicon atoms and each silicon atom bonded to a hydrogen atom, utilizing all ten available valence electrons.
Explanation:
The Lewis structure for Si2H2 involves understanding the bonding and valence electrons of silicon (Si) and hydrogen (H). Silicon has four valence electrons, and hydrogen has one. To achieve the structure, first, count the total number of valence electrons: silicon has four each (so two Si atoms have eight), and there are two hydrogen atoms (contributing one electron each), totaling ten valence electrons. Each hydrogen will form a single bond with a silicon atom, using up two electrons in total, leaving eight electrons to be shared between the two silicon atoms (four electrons for each Si-Si bond). Since each silicon can make four bonds and the hydrogens take up one each, the silicon atoms will use the remaining three valence electrons to form a triple bond with each other.
In the Lewis structure, the silicon atoms are bonded to each other with a triple bond (Si≡Si), and each silicon atom is bonded to a hydrogen atom (Si-H).
1. When adding strong base to a buffer, why can we assume the equilibrium value of the OH- is zero?
Answer:
When adding strong base to a buffer, we assume the equilibrium value of the hydroxyl ion (OH-) is zero because all hydroxyl ion (OH) react with hydrogen ion (H+) forming water. So there is no hydroxyl ion (OH-) left and values of hydroxyl ion (OH-) is become zero.
Hydrogen ion is released by weak acid which is present in the buffer solution.
is ammonium hydroxide a strong base
Answer:
No
Explanation:
Ammonium hydroxide is a weak base and not a strong base.
What is a base?
A base is any substance that interacts with water to produce or yield excess hydroxide ions in an aqueous solution.A strong base is one that ionizes completely in solution. Most strong bases are hydroxides of alkali and alkaline earth metals.
A weak base is one that partially or slightly ionizes in an aqueous solution.
Such is ammonium hydroxide;
NH₃ + H₂O ⇄ NH₄⁺ + OH⁻
In the ionization of a weak base, the process results in an equilibrium reaction.
the muscle layer of the heart is known as the
Answer:
Myocardium
Explanation:
myo means "of muscle" or "relating to muscle"
cardium denotes tissues or cells that are associated with the heart.
The myocardium is an involuntary (we don't have to actively contract it), smooth muscle. The cells that make up the muscle are called cardiomyocytes.
These cells/tissues are hugely important for the normal functioning of the heart, and disruption is associated with diseases such as ischemic heart disease.
What is the objective of sustainable development? Sustainable development is concerned with meeting needs without jeopardizing the needs of generations.
Answer:
To meet the needs of the present without jeopardizing that of the future.
Explanation:
Sustainable development applies to all faculties of resource allocation. Most available resources are limited in their capacity to satisfy our limited human wants.
Sustainable development is such development geared towards satisfying the developmental needs of our present generation without endangering those of the future generations. It allows for safe and efficient use/allocation of resources to meet wants. Conservation of resources is an approach towards sustainable development. The use of recycled materials is one method of attaining the obligations of sustainable development.Answer:
Explanation:
Present
Future
How long ago did the solar system form?
a. 5 million years
b. 5 billion years
c. 5 trillion years
Answer:
5 Billion Years to form
Explanation:
Approximately 4.6 billion years ago, the solar system was a cloud of dust and gas known as a solar nebula. Gravity collapsed the material in on itself as it began to spin, forming the sun in the center of the nebula.
what is caliper used for
A caliper is a device used to measure the distance between two opposite sides of an object.
What conversion factor would you use to find the number of moles in 3.52x10^24 molecules
Answer:
Conversion factor is 6.022 ×10^23 molecules/mole.
Number of moles is 5.845 moles
Explanation:
We are given;
3.52 × 10^24 molecules
Required to determine the conversion factor\
We know that according to the Avogadro's constant;
1 mole of a compound contains 6.022 ×10^23 particles
Therefore, 1 mole of a molecular compound contains 6.022 ×10^23 molecules.
Thus, the conversion factor in this case would be 6.022 ×10^23 molecules/mole.
Such that; 3.52 × 10^24 molecules are equivalent to;
= 3.52 × 10^24 molecules ÷ 6.022 ×10^23 molecules/mole.
=5.845 moles
Thus, the conversion factor is 6.022 ×10^23 molecules/mole.
Number of moles is 5.845 moles
Compare and contrast the properties of acids and bases. Include two similarities and two differences.
Explanation:
Similarities
All acids and bases dissociate into ions, whether fully or partially, when dissolved in waterBoth are good conductors of electricity because they are made of electrolytesDifferences
Acids dissociate in water to create more H+ ions that lower the pH of the solution while bases dissociated into OH- that increase the pH of the water Acids are mainly proton donors while bases are proton acceptors
How many moles of calcium carbonate-CaCO3 = 4.15 g
Answer:
Number of moles = 0.042 mol
Explanation:
Given data:
Number of moles = ?
Mass of calcium carbonate = ?
Solution:
Formula:
Number of moles = mass/ molar mass
now we will calculate the molar mass of calcium carbonate.
atomic mass of Ca = 40 amu
atomic mass of C = 12 amu
atomic mass of O = 16 amu
CaCO₃ = 40 + 12+ 3×16
CaCO₃ = 40 + 12+48
CaCO₃ = 100 g/mol
Now we will calculate the number of moles.
Number of moles = 4.15 g / 100 g/mol
Number of moles = 0.042 mol
. Minerals are classified according to their
a. color.
b. origin
C. composition.
d. specific gravity.
Answer:
C - composition
Explanation:
Minerals can be classified based on their chemical composition which is expressed in their physical properties. Minerals are described by their physical properties which includes color, crystal form, hardness, density and luster.
The chemical composition is not only used for the classification of minerals, minerals are also classified by determination of internal structures accomplished through the use of X rays.
How many covalent bonds does and oxygen stone usually make in forming covalent compounds?
a) 5
b) 3
c) 2
d)4
e)1
Answer: Oxygen usually forms two covalent bonds or a covalent double bond.
Explanation:
A covalent bond is formed by the sharing of 2 electrons, 1 electron from each of the atoms sharing their electrons.
The number of bonds that each element can form depends on the number of valence (outermost) electrons it contains. Oxygen has 6 electrons in its valence shell and needs 2 more electrons thereby forming a double bond.
11.
In the 1930s, how did Dobzhansky and Mayr explain the origin of species?
Species originate due to gradual adaptations to the environment.
Species originate from interbreeding.
Species originate through allopatric speciation.
Species originate due to behavioral changes.
Answer:
species originate through allopatric speciation:
Have a good day! :)
Answer:
species originate through allopatric speciation
Explanation:
you need to make 1.5L of 1.0M HCl from a stock solution of 12.0M HCl. How many L of the stock solution do you need?
Answer:
125 ml of HCl
Explanation:
The molarity of the stock solution to determine how many milliliters would contain 1.5 moles of HCl. Since a concentration of 12.0 mol/L means that you get 12.0 moles of hydrochloric acid per liter of solution,
Concentration of required HCl (C1) = 1.0M
Volume of required HCL (V1) = 1500 ml
Concentration of stock HCl (C2) = 12M
Volume of stock HCL (V2) = ?
C1V1 = C2V2
V2 = C1V1/C2 = 1*1500/12 = 125 ml
To make a 1.0M HCl solution from a stock solution of 12.0M HCl, you need to take 125mL of the stock solution and dilute it to a final volume of 1.5L.
Explanation:To make a 1.0M HCl solution, you need to dilute a stock solution of 12.0M HCl. The formula to calculate the volume of stock solution needed is (C1 x V1) = (C2 x V2), where C1 is the concentration of the stock solution, V1 is the volume of stock solution needed, C2 is the desired concentration, and V2 is the final volume. In this case, C1 = 12.0M, V2 = 1.5L, and C2 = 1.0M.
Plugging in these values into the formula:
(12.0M x V1) = (1.0M x 1.5L)
Solving for V1:
V1 = (1.0M x 1.5L) / 12.0M = 0.125L or 125mL.
Therefore, you need to take 125mL of the stock solution to make 1.5L of 1.0M HCl.
What is the total amount of heat released when 94.0 g water at 80.0 °C cools to form ice at −30.0 °C?
Answer:
The total amount of heat released is 68.7 kJ
Explanation:
Given that:
mass of water = 94.0 g
moles of water = 94 / 18.02 = 5.216
80⁰C ------> 0⁰C --------> -30⁰C
Q1 = m Cp dT
= 94 x 4.184 x (0 - 80)
= -31463.68 J
= -31.43 kJ
Q2 = 6.01 x 10^3 x 5.216
= - 31348.16 J
= -31.35 kJ
Q3 = - 94 x 2.09 x 30
= - 5893.8 J
= -5.894 kJ
Total heat = Q1 + Q2 + Q3 = -31.43 kJ + (-31.35 kJ ) + (-5.894 kJ ) = -68.7 kJ
Total heat released = -68.7 kJ
Note that the "negative sign" simply indicates heat released, therefore no need to put it in the answer.
The total amount of heat released is 68.7 kJ.
Given:
Mass of water = 94.0 g
Moles of water = 94 / 18.02 = 5.216
Transformation of heat:80⁰C ------> 0⁰C --------> -30⁰C
Q₁ = m*Cp*dT
= 94 * 4.184 * (0 - 80)
= -31463.68 J
Q₁ = -31.43 kJ
Q₂ = 6.01 * 10³ * 5.216
= - 31348.16 J
Q₂ = -31.35 kJ
Q₃ = - 94 * 2.09 * 30
= - 5893.8 J
Q₃ = -5.894 kJ
Total heat = Q₁ + Q₂ + Q₃
Total heat = -31.43 kJ + (-31.35 kJ ) + (-5.894 kJ ) = -68.7 kJ
Total heat = -68.7 kJ
Total heat released = -68.7 kJ
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Element Y has two natural isotopes Y-63 (62.940 amu) and Y-65 (64.928 amu). Calculate the atomic mass of element Y, given the abundance of Y-63 is 69.17%?
Answer:
Average atomic mass = 63.553 amu.
Explanation:
Given data:
Abundance of Y-63 = 69.17%
Abundance of Y-65 = 100 - 69.17 = 30.83%
Atomic mass of Y-63 = 62.940 amu
Atomic mass of Y-65 = 64.928 amu
Atomic mass of Y = ?
Solution:
Average atomic mass= (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass= (62.940×69.17)+(64.928×30.83) /100
Average atomic mass = 4353.560 + 2001.730 / 100
Average atomic mass = 6355.29 / 100
Average atomic mass = 63.553 amu.
To calculate the atomic mass of element Y, use the formula that considers the abundance of each isotope and its corresponding mass.
Explanation:To calculate the atomic mass of element Y, we need to consider the abundance of each isotope and its corresponding mass. We can use the formula:
Average atomic mass = (mass of isotope A x abundance of isotope A) + (mass of isotope B x abundance of isotope B)
Plugging in the values:
Average atomic mass = (62.940 amu x 0.6917) + (64.928 amu x 0.3083) = 63.55 amu
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Match the academic requirements with the careers . Cosmetologist
Answer:
Technical program - cosmetologist
To match academic requirements with a career as a Cosmetologist, one must attend Beauty School and obtain certification, with an option for higher learning for career enhancement. This career is suitable for those with an interest in beauty, who enjoy client interaction, and who are willing to engage in continuous learning.
To align academic requirements with careers such as that of a Cosmetologist, you must consider several factors. You would need to attend a Beauty School to obtain professional certification and perhaps, depending on where you aim to practice, a state license. The nature of this career fits those who have an artistic flair and a passion for beauty and personal care. While a college degree is not typically required for a career in cosmetology, attending a reputable institution can enhance your skills and open doors for career advancement.
For anyone evaluating if a cosmetology program matches their career goals, you must contemplate if you have an interest in delivering beauty services and if you wish to continuously develop your service portfolio. Given its hands-on nature, consider, too, if you enjoy interacting with clients on a day-to-day basis. Furthermore, as a Cosmetologist, continuous learning to keep up with beauty trends and health regulations is essential. Finally, determine if the role satisfies your personal goals for creativity, social interaction, and potentially owning a business.
Different careers and their associated academic requirements will vary. Some careers, like those in law or medicine, require extensive postgraduate education, licenses, and certifications, whereas for others, such as a Cosmetologist, the educational path is less academic and more skills-focused. However, even within such vocational careers, individual programs may have special requirements, including additional coursework in health, safety, or business management, to ensure you are well-prepared for the challenges of the job.
Barium chloride is a binary compound because it contains
Answer:
Ba Cl 2
Explanation:
A 13.8 g sample of X reacts with a sample of Y to form 68.3 g of XY.What is the mass of Y that reacted
54.5 grams of Y reacted with 13.8 g sample of X to form 68.3 g of XY.
Explanation:
In chemical reaction the mass remains conserved until the dissipation or lost is shown. In the question it is mentioned that 13.gm of X reacts with some amount of Y to form a product XY of mass 68.3 grams.
The reaction given is addition reaction in which two elements react to for a compound.
X + Y ⇒ XY
So, in the chemical reaction value of mass is put as
13.8 + Y = 68.3
Y = 68.3-13.8
Y = 54.5 grams
Find the number of grams
4.00 moles of CU(CN)2
Answer:
462g
Explanation:
First, let us calculate the molar mass of Cu(CN)2. This is illustrated below:
Molar Mass of Cu(CN)2 = 63.5 + 2(12+14) = 63.5 + 2(26) = 63.5 + 52 = 115.5g/mol
Number of mole of Cu(CN)2 given from the question = 4moles
Mass = number of mole x molar Mass
Mass of Cu(CN)2 = 4 x 115.5
Mass of Cu(CN)2 = 462g
Question 2
What is the freezing point of water in Celcius
0°C
Explanation:
The freezing point of water is zero (0) degrees Celsius. Converted to Kelvin it is 273.15 kelvin. At these temperatures pure liquid water, and at 1 atm, changes to ice. The boiling point of water, on the other hand, is 100 degrees Celsius, temperatures at which liquid changes to a gaseous phase (water vapour).
A constant volume of gas is heated from 25.0ºC to 150.ºC. If the initial pressure was 760. torr, what is the final pressure?
The final pressure of the gas is 1078.79 torr
Explanation:
The initial pressure (P₁)= 760 torr
The initial temperature (T₁)=25°C
The final temperature (T₂)=150°C
The final pressure (P₂)
Since the temperature of the gas is in °C, we need to convert them to Kelvin units
We know that 0°C=273 K
Thus T₁=273+25=298K
Similarly T₂ =273+150=423K
From the Gay-Lussac's law, we know that-
P₁/T₁ = P₂/T₂
Where P₁,P₂,T₁,T₂ covey the meaning as described earlier
Substituting the value we get-
(760/298) = P₂/423
P₂=(760*423)/298
Thus the final pressure of the gas is 1078.79 torr.
hello:) ice is pure liquid which means that it’s a pure substance , is this true? anyone able to correct me if I’m wrong & explain too? Thank you!
Answer:
A pure substance is a substance composed of one substance. It has fixed physical and chemical properties. It has special chemical symbols, which can be expressed by a chemical formula. Water is pure, so what you mean by liquid ice is pure.
Explanation:
Answer:
Ice is a pure liquid
Molality Problems (Need ASAP!) 100 POINTS!!! Thanks :)
1. What is the molality of a solution in which 0.135 moles of CO2 is dissolved in 490mL of water? (1kg of water = 1L of water)
2. What is the molality of a solution in which 23g of NaCl are dissolved in 250g of water?
3. How many moles of HC1 are needed to prepare a 3m (3molal) solution with 1.5Kg of water?
1. 0.2755 M
2. 1.574 M
3. 4.5 moles
Explanation:
Molality is defined as the number of moles of solute dissolved in a kg of solvent;
1)
If 0.135 moles of CO2 is dissolved in 490mL of water, how much moles are in 1000 mL (1 kg) of water;
0.135 : 490
x : 1000
490x = 1000 * 0.135
x = 135 /490
x = 0.2755 moles
= 0.2755 M
2)
If 23g of NaCl are dissolved in 250g of water, how much NaCl in dissolve in 1000g (1kg) of water;
23 : 250
x : 1000
250x = 1000 * 23
x = 23000/250
x = 92 g
To find many moles of NaCl are in 92g (Remember molar mass of NaCl is 58.44 g/mol) ;
92/ 58.44
= 1.574 moles
= 1.574 M
3)
A 3 M HCl solution means there are 3 moles of HCl in 1L (1 kg) water.
3 : 1
x : 1.5
x = 1.5 * 3
x = 4.5
= 4.5 moles
What is the molarity of 0.50 liter of an aqueous solution that contains 0.20 mole of NaOH (gram-formula mass = 40. g/mol)?
Answer:
0.4mol/L
Explanation:
Data obtained from the question include:
Number of mole of NaOH(solute) = 0.20 mole
Volume of solution = 0.50 L
Molarity =.?
Molarity is simply mole of solute per unit litre of a solution. This can represented mathematically as:
Molarity = mole of solute /Volume of solution
Molarity of NaOH = 0.2mol/0.5L
Molarity of NaOH = 0.4mol/L
Answer:
0.4 mol
Explanation: