Answer:
See explanation for details
Explanation:
a) Now from the data given, recall that;
N/No = (1/2)t/t1/2
Where,
N= amount of radioactive material remaining at time t
No= Amount of radioactive material originally present
t= time taken for N amount of radioactive material to remain
t1/2= half life of radioactive material
So,
N/No = (1/2)^20,000/5730
N/No = (1/2)^3.49
N/No = 0.089
Since the fraction N/No is the fraction remaining after t years, then;
Percentage of Carbon-14 left after 20,000 years = 0.089 * 100 = 8.9%
b) From;
0.693/t1/2 = 2.303/t log No/N
Given that N = 0.42 No
Hence;
0.693/5730 = 2.303/t log (No/0.42No)
1.21 * 10^-4 = 0.87/t
t= 0.87/1.21 * 10^-4
t = 7190 years
c) Radiocarbon dating is a method of obtaining the age of an object derived from plants or animals by comparing the Carbon-14 activity of living things with that of the sample under study. Due to contamination, the age of artifacts obtained by Carbon-14 dating may yield outlying figures.
Which EMW can humans see?
Answer:
visible light waves are the only electromagnetic waves we can see
How many neutrons does an element have whose electronic formula is 1s²2s²2p⁵
Answer:
it have 10 neutrons and it is Fluorine(F).
You put 0.025 L of 3.0 M sulfurous acid into a volumetric flask and made a 1.00-L solution. What is the
concentration of the new solution?
Answer:
0.075 M
Explanation:
Step 1: Given data
Initial concentration of the sulfurous acid solution (C₁): 3.0 MInitial volume of the sulfurous acid solution (V₁): 0.025 LFinal concentration of the sulfurous acid solution (C₂): ?Final volume of the sulfurous acid solution (V₂): 1.00 LStep 2: Calculate the final concentration of the sulfurous acid solution
If we add water to the initial solution, we will get a diluted solution. We can calculate the final concentration using the dilution rule.
C₁ × V₁ = C₂ × V₂
C₂ = C₁ × V₁ / V₂
C₂ = 3.0 M × 0.025 L / 1.00 L
C₂ = 0.075 M
Indicate whether each of the following statements about Joseph Priestley’s experiment is an observation or an inference.
The candle stayed lit longer because the plant gave off oxygen.
The candle went out when it was placed in a closed jar.
The candle stayed lit longer in closed jar when a plant was present.
Answer:
Inference — The candle stayed lit longer because the plant gave off oxygen.
Observation — The candle went out when it was placed in a closed jar.
Observation — The candle stayed lit longer in closed jar when a plant was present.
Explanation:
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(If helpful)
Joseph Priestley discovered the element oxygen which is most precious for living. He discovered the need of oxygen to respire and release by plants during photosynthesis.
What is photosynthesis?Photosynthesis is the process of synthesis of glucose using carbon dioxide and water with the aid of light energy. The process makes energy for all the living organism in earth.
Plants uptake carbon dioxide and release oxygen during photosynthesis which makes oxygen abundant in the atmosphere.Thus, presence of plants give us air and remove carbon dioxide formed by respiration.
Priestley's conducted an experiment with a mouse placed in a closed jar and candle light inside. When the jar is close, there will be no air inside make the rat perish and candle light off. When he placed a plant inside the jar it released oxygen which made the rat alive a little longer.
Candle light stayed a lit longer by the presence of the plant. Thus option A is correct. Priestley concluded that buring needs oxygen.
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Select True or False: A mixture made from 10 mL of 1 M HCl and 20 mL of 1 M CH3COONa would be classified as a buffer solution.
Answer:
True.
Explanation:
There are three ways to make a buffer.
a. Generating a solution of a weak acid and its conjugate base.
b. Adding to a solution of a weak acid a certain quantity of
strong base, so that the acid remains in excess.
c. adding a limited amount to a conjugate base solution
of strong acid so that the base remains in excess.
We are in c, in this situation.
How do you calculate, pH? We apply Henderson Hasselbach.
pH = pka + log (mmoles base - mmoles acid)/ mmoles acid
pH = pKa + log ((20 ml . 1 M - 1 ml . 10M) / 10 mmoles
pH = 4.76 + log 1 → 4.76 ⇒ pH = pKa
With ionic compounds, the ion charge is the same as the ___ number.
A. methylation
B. anion
C. cation
D. oxidation
Answer:
D. Oxidation
Explanation:
The oxidation state of a pure element is always equal to zero and the oxidation state for a pure ion is equivalent to its ionic charge.
Which event takes place first in the stages before the brith of a star
Answer:
nuclear fusion
Explanation:
gravity pulls gas and dust together a protostar forms as mass increases nuclear fusion begins under high pressure
11. Which of the following statements describe anions? Select all that apply.
They have gained electrons.
Negatively charged ions.
Positively charged ions.
They have lost electrons.
Answer:
They have gained electrons.
Negatively charged ions.
Explanation:
Anions are negatively charged ions because they have gained electrons. Therefore, option (A), (B) is correct.
What are anions?Ions form from the atoms and electrons that have either gained or lost one or more valence electrons which would create either a positive or a negative charge.
The ions that possess a negative charge are called anions and the ones that possess a positive charge are called cations. Since both of them have opposite charges, they get attracted to one another.
Anions are negatively charged ions and are formed when non-metal gains electrons. The atoms gain one or more than one electron, they have a net negative charge. A few examples of anions are Iodide (I⁻), and hydroxide (OH⁻).
The chloride anion Cl⁻ would show that it has one less proton than the total number of electrons in it which gives it a minus charge.
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Can somebody please help me with these 3 questions ? and explain them so I can understand them
Explanation:
1. The group of atoms above bonded together is
called a molecule.
Therefore,
Option A is correct ✔
2. There's 4 H-atom in 2H₂O
Therefore,
Option A is correct ✔
3. There's 2 molecules in 2Al₂O₃
Therefore,
Option A is correct ✔
URGENT:
(I’ll give first person brainlyist)
What type of elements typically become positively charged ions?
Answer:
The elements that are commonly positive ions are metals. But there are a few gases that can become positively charged by losing electrons.
Typically, when metals and non-metals interact, the metals' electrons are transferred to the non-metals. In contrast to non-metals, which form negatively charged ions, metals form positively charged ions.
The non-metal picks up electrons and gets negatively charged, whereas the metal loses electrons and gets positively charged. Cations and anions are the names given to positively and negatively charged ions, respectively.
Metals are the elements that lose electrons to generate positively charged ions (cations) in all chemical processes, with the exception of hydrogen. Metals are electropositive elements as a result.
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Calculate the total heat flow, qtotal, when 15.0 g of water is cooled from 115°C to -20.0°C. The heat of fusion of water is 335 J/g, and the heat of vaporization of water is 2.26 kJ/g. The specific heat of liquid water is 4.183 J/gºC, the specific heat of steam is 2.0 J/g°C, and the specific heat of ice is 2.1 J/g°C.
Answer:The dependence of the density, viscosity, and heat capacity of a gas on the temperature. ... C-±r*j~d. (1.19). It Is very difficult to use Equation (1.19) for arbitrary quantities. Oi due tc the ... Equation (1.39) Is also valid for polyatomic g~ases whose tmolecules ... Nikuradze which involved the flow of water in long cylindrical tubes.
Explanation:
The total heat flow of water from the state of ice to vapor form is equal to 38,925 J.
How do we calculate total heat?Total heat flow from ice to vapor form of water will be calculated as:
Total heat = Heat of fusion + Heat of vaporization
Given that, mass of water = 15g
Heat of fusion of water = 15g × 335J/g = 5025 J
Heat of vaporization of water = 2.26kJ/g × 15g = 33.9 kJ = 33900 J
Total heat flow = 5025 + 33900 = 38925 J
Heance total flow of heat is 38,925 J.
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I NEED RIGHT NOW OR I GET AN F!!!!! HELP!!!!!
Describe the three main types of plate boundary interactions:
Divergent boundaries:
Convergent boundaries:
Transform boundaries:
Answer:
boundary interactions: areas where plates move away from each other forming mid-ocean ridges or rift valleys.
divergent boundaries: this happens when 2 tectonic plates move away from each other. along these boundaries earthquakes and magma are common as they are rise from the mantle to the sruface making new oceanic crust.
convergent boundaries: this is an area on earth where 2 or more lithospheric plates collide. they will slide under one another creating a subduction.
transform boundaries: transform boundary is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subduction zone.
Explanation:
lithosperic means the solid outer part of the earth.
hope this helps and good luck! :) <3
The fact that the four new elements are Period 7 of the table means that they all
A.have seven shells of electrons
B. have seven valence electrons
C. form ions with charges of 7+
D. have an effective nuclear charge of 7+
Answer:
C
Explanation:
form ions with charges of 7+
Mendeleev created this table as he noticed that a
metal that was reactive with water always seemed to
come before a metal that was also very reactive and
then a less reactive metal, noticing a pattern in
chemical properties. But what group of atoms did he
totally leave out? Why do you think that is?
Answer:
Mendeleev had left the noble gases out of his periodic table.
Explanation:
Mendeleev's periodic table is pictured in the image attached to the question.
Mendeleev's table obviously lacked the noble gases. The reason for this grave omission is simple; the noble gases were not known as at the time when he formulated his periodic table. There weren't any known elements whose properties were similar to the properties of the noble gases. This would have lead him to suspect their existence.
what was the slope of the best fit line
Answer:
sorry I don't really know
What is the maximum number of electrons on the outer layer of atoms?
Answer:
8 electrons
Explanation:
explain why sodium trioxocarbonate is an alkaline
Answer:
Sodium triocarbonate (IV) is hydrolyzed in water.
Explanation:
" When sodium carbonate is added to water, it hydrolyses to give sodium bicarbonate and sodium hydroxide (a strong base). As a result, the solution becomes alkaline. ... This is because the liberated metals react with water."
Alkaline: of, relating to, containing, or having the properties of an alkali or alkali metal : basic especially, of a solution (water is a solution).
I hope this answers your question! Let me know if it doesn't!
Chromium oxide reacts with hydrogen sulfide gas to form chromium
Answer:
true
Explanation:
Which statement best explains why an object appears green in sunlight?
O The object absorbs most white light and refracts most green light.
O The object refracts most white light and absorbs most green light.
O More green light is absorbed while more red and blue light is reflected.
More green light is reflected while more red and blue light is absorbed.
Answer: A
Explanation: not sure what to say but it’s for sure A it makes sense :) good luck !
The statement best explains why an object appears green in sunlight is (D) More green light is reflected while more red and blue light is absorbed.Hence the correct option is (D).
What is Reflection ?Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.
Common examples include the reflection of light, sound and water waves.
Colored objects look the way they do because of reflected light. When sunlight is shined on a green leaf, the violet, red and orange wavelengths are absorbed. The reflected wavelengths appear green.
Therefore, The statement best explains why an object appears green in sunlight is (D) More green light is reflected while more red and blue light is absorbed.Hence the correct option is (D).
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what is the main function of the skeletal system in relation to the muscular system
A. to produce enzymes that help muscles repair themselves
B. to provide attachment points for muscles
C. to produce muscle cells inside the bone marrow
D. to assist muscles in growth and development
Answer:
B
Explanation:
muscles attach to the skeleton in order for the body to be sturdy. as you probably know, the skeletal system is mainly used for providing support to the body so it won't fall down.
What is the expected major organic product from the treatment of 4-methyl-2-pentyne with excess hydrogen in the presence of a platinum catalyst?
a. (E)-4-methyl-2-pentene
b. (Z)-4-methyl-2-pentene
c. (E)-2-methyl-2-pentene
d. (Z)-2-methyl-2-pentene
e. 2-methylpentene
Answer:
(Z)-4-methyl-2-pentene
Explanation:
Hydrogenation is a syn addition. This implies that the hydrogen atoms add to the same face of the multiple bond.
Hence, if we have the alkyne, 4-methyl-2-pentyne which reacts with excess hydrogen in the presence of a platinum catalyst, we obtain (Z)-4-methyl-2-pentene since the hydrogen atoms add on the same side of the multiple bond.
Which action can speed up the rate of a chemical reaction?
A removing a catalyst
B lowering the reactant concentration
C lowering the temperature
D breaking a reactant into smaller pieces
The action can speed up the rate of a chemical reaction is breaking a reactant into smaller pieces.
What is rate of reaction?Rate of a chemical reaction tells about the duration of time at which reaction complete.
Rate of reaction is also define as the rate of change of concentration of reactant with respect to the time. So, concentration of reactant is directly proportional to the rate of a reaction and wherever we increases the surface area of reactant rate increases as reactant will participate through large possible side. Catalyst also speeds up the reaction without being involved in it and high temperature also increases the kinetic energy of the reactant to do effective collision.
Hence, option (d) is correct i.e. breaking a reactant into smaller pieces increases the rate.
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Describe the famous experiment related to gravity that Galileo may have performed. Include the results. Also, state whether the results support the law of gravity. Explain your answer.
Answer:
Galileo performed a famous experiment where he used a ball rolling on a ramp (inclined plane) to study the motion of objects under the influence of gravity. The ramp allowed him to make more precise measurements because the ball moved more slowly along the ramp than if it were simply dropped. Galileo discovered through this experiment that the objects fell with the same acceleration, proving his prediction true, while at the same time disproving Aristotle's theory of gravity (which states that objects fall at speed proportional to their mass). Galileo's conclusion from this thought experiment was that no force is needed to keep an object moving with constant velocity. Newton took this as his first law of motion. One result of the experiment surprised Galileo, and one surprises us. Galileo found that the heavy ball hit the ground first, but only by a little bit. Except for a small difference caused by air resistance, both balls reached nearly the same speed. And that surprised him. According to history, Galileo’s experiment on falling bodies largely contributed to Isaac Newton’s Law of Gravity. In Galileo’s experiment, he is said to have dropped balls from the Leaning Tower of Pisa. The balls were made of the same material but had different masses. Galileo set out to prove that the time it took for these objects to reach the ground would be the same. Galileo proved that objects reached the ground at the same time,
Explanation:
I think this is right & I hope this helped
Galileo demonstrated that gravity causes things of various masses to fall with the same acceleration by dropping weights from the leaning Tower of Pisa.
What is gravity?Gravitational force is the force by an object attracts other objects into its center of mass. Earth attracts every objects on its surface to the ground by gravitational pull.
The outcome of Galileo's gravity experiment supports the equivalence principle, which forms the basis of general relativity, Albert Einstein's theory of gravity.
According to this theory, an object's inertial mass which determines how quickly it accelerates when a force is applied and gravitational mass which determines how much of a gravitational force it experiences are the same. The conclusion is that an object's acceleration due to gravity is dependent of both its mass and composition.
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What is the pH of a solution in which [H 3O +] = 3.8 × 10 -8 M?
Answer:
The answer is 7.42Explanation:
The pH of a solution can be found by using the formula
[tex]pH = - log [ { H_3O}^{+}][/tex]
From the question we have
[tex]pH = - log(3.8 \times {10}^{ - 8} ) \\ = 7.420216...[/tex]
We have the final answer as
7.42Hope this helps you
Based on its location in the periodic table, what can most likely be predicted about sulfur?
Answer:
A
Explanation:
Edg answer
Answer:
C
Explanation:
How many moles of CO2 are produced when 2.5 moles of O2 react according to the following equation? C3H5 + 5 O2 → 3 CO2 + 4 H2O
Answer:
1.5
Explanation:
C3H5 + 5 O2 → 3 CO2 + 4 H2O
3.75 moles of CO2 are produced when 2.5 moles of O2 react.
The following chemical equation is given:
C3H8 + 5O2 → 3CO2 + 4H2O
Based on this balanced chemical equation, 5 moles of O2 react to produce 3 moles of CO2
Stoichiometrically, if 2.5 moles of O2 react, then:
2.5 × 3/2 moles of CO2 will be produced
= 2.5 × 1.5
= 3.75moles
Therefore, based on the balanced chemical equation between propane (C3H8) and oxygen (O2), 2.5 moles of O2 will produce 3.75moles of CO2.
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among the intermolecular forces,which forces are typically the weakest
Its metallic. I just took the quiz.
D. London dispersion forces
plzz helpp mee putttt
Answer:
The first one is C and the second one is A
Explanation:
Looking at the picture, the horse-like fossil was able to walk and run
The second one is sedimentary because fossils are preserved in the sedimentary rock
Use the reaction given below to solve the problem that follows: Calculate the mass in grams of aluminum metal required to react with 115 g of oxygen gas.
4 Al + 3 O2 ——> 2 Al2O3
Answer: _____ grams Al
Answer:
129.4g
Explanation:
Reaction equation":
4Al + 3O₂ → 2Al₂O₃
Given mass of oxygen = 115g
Unknown:
mass of aluminum metal that reacted;'
Solution:
We need to convert the given mass of O₂ to mole;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of O₂ = 2(16) = 32g/mol
Number of moles = [tex]\frac{115}{32}[/tex] = 3.6mol
From the balanced reaction equation:
3 moles of O₂ reacted with 4 mole of Al
3.6 moles of O₂ will react with [tex]\frac{3.6 x 4}{3}[/tex] = 4.8mol
Mass of Al = number of moles x molar mass
Mass of Al = 4.8 x 27 = 129.4g
critically evaluate the role of human beings in perpetuating climate change
Explanation:
To many people around the world, earth is considered to be a place for human beings to live together as one big family. It provides us shelters, foods, water, and the most beautiful sceneries. Without doubt, we are bound to nature. However because the existence of climate change, which according to scientists is defined as the long term changes over climate including temperature and rainfall, the world would probably end up with devastated ecosystem, extinct wildlife, and most importantly despondent humans. The impact that it has on us is incredibly strong that it affects the system of human lives and wildlife. Global warming, precipitating weather, glaciers, and rising of sea level are no more phenom