Answer: Option (C)
Explanation: Uranium- 238 is an unstable isotope of uranium. It is one of the most effective isotope used for radioactive dating in order to determine the age of a rock that is about billions of years old. It contains an unstable nucleus that undergoes continuous decay, until it reaches a stable environment. It has a half life of approximately 4.5 billion years and majority of the uranium that are present on earth at present are all uranium- 238 and they are constantly decaying. When uranium completely decays, it then gets converted into lead, which is a stable element.
The most common radioactive method used to date rocks is Uranium-Lead dating method.
Thus, the correct answer is option (C).
Read the clues. I have scales. My skin is dry.I breathe with lungs. I lay tough,leathery eggs. what vertebrate what am I ? A. reptile B. amphibian C. mammal D. bird help me plz ASAP
Which is generally true of enzymes in cells?
A) Enzymes allow reactions to proceed at body temperature.
B) Enzymes require co-enzymes to be effective.
C) Enzymes are organic compounds that the body needs in small amounts.
What does a subscript indicate in a chemical formula?
Explanation:
A subscript is a number that is placed below an alphabet on the bottom right side.
For example, for [tex]H_{2}[/tex] molecule 2 is the subscript.
A subscript indicates the number of atoms present in a substance or molecule.
For example, in [tex]H_{2}SO_{4}[/tex] the subscripts indicate that there are two hydrogen atoms, one sulfur atom, and four oxygen atoms.
An atom is determined to contain 34 protons, 36 electrons, and 34 neutrons. what are the mass number and charge of this atom or ion?
Which of the following shows the path followed by nerve impulses in a reflex?
A.motor neurons → interneurons in brain → sensory neurons
B.sensory neurons → interneurons in brain → motor neurons
C.motor neurons → interneurons in spinal cord → sensory neurons
D.sensory neurons → interneurons in spinal cord → motor neurons
Sensory neurons, interneurons in spinal cord, motor neurons shows the path followed by nerve impulses in a reflex. Sensory neurons are the neurons that carry information from the environment externally to the central nervous system (CNS) mainly brain and motor neurons are those which carry information from CNS to other parts.
A human perceives something then by sensory neurons the information goes to CNS and that information is further passed by interneurons in spinal cord and is further passed by motor neurons from CNS to other parts to perform stimulus of perception.
what is the name and the chemical symbol for the gas that caused the professor's voice to change - from the movie flubber
Answer:
Helium gas, symbol He
Explanation:
The gas that causes voice to change upon inhalation is helium which belongs to the inert gas/noble gas series in the periodic table. The chemical symbol is He.
When He gas is inhaled it fills up the vocal tract and replaces some of the air present in the cavity. Now, the density of He is much lower than that of air as a result the speed of sound as it passes through the vocal cavity increases which leads to a change in voice.
If another scientist tests the substance using iodine, which macromolecule is the scientist testing for? question 27 options: carbohydrate lipid protein
What 3 things can molecules moving with kinetic energy do?
Explanation:
Kinetic energy is defined as the energy obtained by the molecules of a substance because of their motion.
Hence, when a substance or object is moving from its initial position then it means it has some amount of kinetic energy.
So, if molecules are moving then they have possessed kinetic energy and 3 things these molecules will do are as follows.
They will collide with the walls of a container or object in which they are placed.Also, molecules tend to collide with each other.And, they are able to pass or move through a pore.explain why carbon-14 and nitrogen-14 are not considered isotopes.
Taking into account the definition of isotopes, carbon-14 and nitrogen-14 are not considered isotopes because they have have different atomic numbers.
First of all, all atoms are made up of subatomic particles: protons and neutrons, which are part of their nucleus, and electrons, which revolve around them. Protons are positively charged, neutrons are neutrally charged, and electrons are negatively charged (electrons).
On the other side, the mass number tells us the total number of particles in the nucleus. That is, the mass number is the sum of the number of protons and the number of neutrons in the atomic nucleus:
Mass number = (number of protons) + (number of neutrons)
Then, atomic number is defined as the number of protons or number in the atomic nucleus.
The same chemical element can be made up of different atoms, that is, their atomic numbers are the same, but the number of neutrons is different. These atoms are called isotopes of the element.
In this case, the elements carbon and nitrogen have different atomic numbers (this is different numbers of protons), and the same mass number. So, carbon-14 and nitrogen-14 are not considered isotopes.
In summary, carbon-14 and nitrogen-14 are not considered isotopes because they have have different atomic numbers.
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Chemical reactivity of metals increases
Chemical reactivity of nonmetals increases
Chemical reactivity of metals remains unchanged
Chemical reactivity of nonmetals remains unchanged
Answer: The correct answer is chemical reactivity of metals increases.
Explanation:
Chemical reactivity is defined as the tendency of an element to loose of gain electrons.
Metals are the elements which looses electrons and hence, their chemical reactivity will be the tendency to loose electrons. Their chemical reactivity increases as we move from top to bottom in a group. This is so because, the electron get added up in the new shell. So, the electron in the outermost orbital gets far away from the nucleus. And hence, this will be lost easily. Thus, the chemical reactivity gets increases.
Non-metals are the elements which gains electrons and hence, their chemical reactivity will be the tendency to loose electrons. Their chemical reactivity decreases as we move from top to bottom in a group. As, the electrons get added up in the new shell. So, the the electron in the outermost orbital gets far away from the nucleus. And hence, the electron will be difficult to gain. Thus, the chemical reactivity of non-metals decreases.
Hence, the correct answer is chemical reactivity of metals increases.
The nucleus of an atom is dense and positively charged. What was observed when positively charged particles were radiated onto a gold atom during Rutherford's experiment because of this?
Negative charges were concentrated at the center of the atom.
Particles that struck the center of the atom were repelled.
Particles that struck the edges of the atom were repelled.
Positive charges were distributed all over the atom.
Answer:
Particles that struck the center of the atom were repelled.
Explanation:
In 1911, New Zealand physicist Ernest Rutherford carried out an experiment in order to deepen his knowledge of the atomic model hitherto adopted, which was that of Thomson; in which the atom would be a sphere of positive, non-massive electrical charge, encrusted with (negative) electrons, so that its total electrical charge would be zero.
To carry out such an experiment he bombed a very thin gold leaf (thickness of approximately 10-4 mm), through a beam of alpha particles (α), coming from a sample of polonium. The polonium was inside a lead block, with an orifice, through which only the emissions of alpha particles would be allowed out.
In addition, lead plates with holes were placed in their centers, which would orient the beam towards the gold blade. And, finally, a bulkhead covered with zinc sulfide, which is a fluorescent substance, was placed behind the slide, where it was possible to visualize the path taken by the alpha particles.
At the end of this experiment, Rutherford noticed that most of the alpha particles passed through the slide, did not deflect or retreat. Some alpha particles deflected, and very few receded. In addition, the particles that reached the center of the atom were repelled.
Based on these data, Rutherford concluded that, contrary to what Dalton thought, the atom could not be massive. But in reality, much of the atom would be empty and it would contain a very small, dense and positive nucleus.
A syringe contains 0.65 moles of he gas that occupy 750.0 ml. what volume (in l) of gas will the syringe hold if 0.35 moles of ne is added? a syringe contains 0.65 moles of he gas that occupy 750.0 ml. what volume (in l) of gas will the syringe hold if 0.35 moles of ne is added? 1.9 l 4.9 l 2.1 l 0.87 l 1.2 l
Answer:
The correct answer from the given options is option 1.2 L.
Explanation:
Volume of the gases when 0.65 moles of gas are present = [tex]V_1=750 mL=0.750 L[/tex]
Volume of the gas when there 0.35 moles of gas are added= [tex]V_2[/tex]
[tex]n_1=0.65 moles,n_2=0.65+0.35 moles=0.10 moles[/tex]
According Avogadro law of gases:
[tex]\frac{V_1}{n_1}=\frac{V_2}{n_2}[/tex]
[tex]V_2=\frac{V_1\times n_2}{n_1}=1.15 L[/tex]
The closest answer from the given options is option 1.2 L.
From the explanation, we are given that:
The mole of gas [tex]{n_1}[/tex] = [tex] 0.65 moles[/tex]The volume it occupies [tex]{V_1}[/tex] = [tex] 750.0ml[/tex] = [tex]0.750L[/tex]Mole of Neon = [tex]0.35ml[/tex]The volume of gas it occupies when [tex]0.35moles[/tex] = [tex]{V_2}[/tex] (unknown)
Therefore we have:
[tex]{n_2}[/tex] = [tex]0.65[/tex] + [tex]0.35[/tex] = [tex]0.10moles[/tex] , [tex]{n_1}[/tex] = [tex]0.65moles[/tex]
Further ExplanationTo solve this question, we have to consider the Avogadro’s law, which state that "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules”
The law can be expressed as:
[tex]\frac{V_1}{n_1}=\frac{V_2}{n_2}[/tex]
[tex]V_2=\frac{V_1\times n_2}{n_1}[/tex]
[tex]V_2=\frac{0.750\times 0.10}{0.65}[/tex] = [tex]1.15L[/tex]
[tex]1.2L[/tex]
Therefore, the correct answer is 1.2L
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A syringe contains 0.65 moles of he gas that occupy 900.0 ml. what volume (in l) of gas will the syringe hold if 0.35 moles of ne is added? brainly.com/question/6860167A syringe contains 0.65 moles of he gas that occupy 750.0 ml. brainly.com/question/6442444KEYWORDS:
molessyringeconvertlitresavogradro's lawwhich element belongs to the alkali metal family
The Alkali metals includes
Lithium, Sodium Potassium Rubidium CaesiumFrancium. What are alkali metal?
The alkali metals are the metal which react with water forms alkalies that is strong bases capable of neutralizing acids.
The alkali metals have the high thermal and electrical conductivity, lustre, ductility, and malleability all are the characteristic of metals. Each alkali metal atom contains a single electron in its outermost shell. This valence electron is much more weakly bound than those in inner shells.
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What are two methods of writing a balanced formula?
The two methods used to balance a chemical equation are :
(a) Inspection method.
(b) Algebraic method.
Methods to balance a chemical equationA chemical equation must satisfy the rules of conservation of mass and constant proportions.The rules state that the reactant and product sides of the formula must have the same amount of atoms of each element, the balancing technique is important.(A) Inspection method – In this method, we examine the equation and find the right balance.
Example- [tex]NaCl + BeF_2 = NaF + BeCl_2[/tex]In the above equation, the quantity of chlorine is not the same on both sides. In the product, there are two molecules of chlorine and in the reactant, there is only one. So to balance it, we will put 2 in the reactant.[tex]2NaCl + BeF_2 = NaF + BeCl_2[/tex]
Now, the quantity of nitrogen is two in the reactants but only one in the product. So we put 2 in front of the NaF in the product.[tex]2NaCl + BeF_2 = 2NaF + BeCl_2[/tex].
Now it is balanced.(B) Algebraic method
This approach of balancing chemical equations includes assigning algebraic variables to each species in the imbalanced chemical equation as stoichiometric coefficients.Thus, these are the two methods of balancing a chemical equation.
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Examine the equation.
C3H8(g)+5O2(g)→3CO2(g)+4H2O(l)
In the equation shown, what is the number 4 an example of?
reactant
chemical formula
coefficient
product
Answer:
Coefficient
Explanation:
We can explain this discarting options too. Now, let's write again the chemical equation;
C3H8(g)+5O2(g)→3CO2(g)+4H2O(l)
In a chemical equation, we have two sides. The left side we have the reactants of the reaction, these can be elements or compounds that reacts between each other, to produce another compound or substance. This compounds or elements are on the right side of the reaction. This side we have the products of the reaction of reactants.
Now, as in every situation of life, we need a balance of reactants and products, so, the only way to balance a chemical equation is by putting numbers behind every compound of the reactant and/or products to equal the number of atoms on each side. So if in the reactants we have 3 atoms of C, in the products we need to have the same 3 atoms.
Based on the above explanation, we can say that the number 4 is behind the H2O. This compound is on the side of products, but the number only, do not represent a product, so this option can be discarted.
A reactant cannot be either, cause it's not on the side of reactant.
Chemical formula, could be, if the number were as subscript, but it's not the case, and the chemical formula is composed of symbols.
Finally, as the number that we put behind the compounds work to balance the equation, the only function that these numbers have here, is to be coefficients of the reactions, and furthermore, it will work as mole.
So the correct option is the third one, Coefficient.
What does the space-filling model of a water molecule tell you about the relative size of the atoms?
The atomic number of sodium (na) is 11. how many electrons does a na atom have in its' valence shell?
a. 1
b. 2
c. 4
d. 8
What is the difference between saturated and unsaturated fats answers?
Which type of chemical protective clothing (cpc) protects the wearer against chemical vapors or gases?
A chemist is looking at an electrically neutral atom that has three valence electrons. If she knows the element is a metalloid, which one (or ones) is it?
What mass in grams of ethylene oxide is needed to react with 18 g of water?
When a fluorine atom reacts with a chlorine atom, the bond that forms between them should be
ionic covalent.
nonpolar covalent.
ionic.
polar covalent.
Answer: Polar covalent
Explanation:
Complete the chart. (Remember to enter a 0 if necessary.)
Atomic Number: 3
1s:
2s:
2p:
3s:
3p:
4s:
3d:
4p:
5s:
Answer: The configuration of lithium element is [tex]1s^22s^12p^03s^03p^04s^03d^04p^05s^0[/tex]
Explanation:
Electronic configuration is defined as the representation of electrons around the nucleus of an atom.
Number of electrons in an atom is determined by the atomic number of that atom.
We are given:
Atomic number = 3
The element having atomic number '3' is lithium
The electronic configuration of lithium element is [tex]1s^22s^1[/tex]
Hence, the configuration of lithium element is [tex]1s^22s^12p^03s^03p^04s^03d^04p^05s^0[/tex]
What are valence shell electrons
the idea that light can act as packets led to what new field of science
The idea that light can act as packets led to the discovery of Quantum mechanics. The correct option is A.
What is quantum mechanics?Quantum mechanics is a field of science that deals with the behavior of light and matter. It explains the properties of matter. The electron, proton, and neutron constituency of a matter.
Light has dual nature, which means it can act like both waves and particles. Light is made up of particles that are called photons. Light can also act as quanta or packets, which revealed a new theory, quantum mechanics.
Quantum mechanics help in the field of many inventions, alike circuits, and lasers. Einstein never believed in the theory of quantum mechanics.
Thus, the correct option is A. Quantum mechanics.
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The question is incomplete. Your most probably complete question is given below:
A. Quantum mechanics
B. Nuclear mechanics
C. Electrical mechanics
D. Physical mechanics
Define monosaccharide disaccharide and polysaccharide give at least two examples of each. which of these is the
Monosaccharides, disaccharides, and polysaccharides are types of carbohydrates that consist of one, two, and many sugar molecules, respectively. Glucose and fructose are monosaccharides, sucrose and lactose are disaccharides, and starch and cellulose are polysaccharides.
Explanation:Monosaccharides are the simplest form of carbohydrates and consist of one sugar molecule. Examples include glucose and fructose. Disaccharides consist of two monosaccharide molecules bonded together. Sucrose (table sugar) and lactose (milk sugar) are examples of disaccharides. Polysaccharides are complex carbohydrates made up of many monosaccharides linked together. Starch and cellulose are examples of polysaccharides.
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Gymnasts often practice on foam floors, which increase the collision time when a gymnast falls. What effect does this have on collisions?
The change in momentum needed to stop the gymnast is increased.
The change in momentum needed to stop the gymnast is decreased.
The force exerted by the floor on the gymnast decreases.
The force exerted by the floor on the gymnast increases.
Answer:
The answer in b
Explanation:
Because if she falls the momentum pushes him/her.
I hope this helped! :)
How much work (in j) is involved in a chemical reaction if the volume decreases from 5.00 to 1.26 l against a constant pressure of 0.857 atm?
The work done in the chemical reaction is 3.20 J.
Explanation:The work done in a chemical reaction can be calculated using the formula:
Work (W) = -P ∆V
Where P is the pressure and ∆V is the change in volume. In this case, the volume decreases from 5.00 to 1.26 L against a constant pressure of 0.857 atm. To calculate the work, we need to calculate the change in volume:
∆V = Vfinal - Vinitial = 1.26 L - 5.00 L = -3.74 L
Substituting the values into the formula, we have:
Work (W) = -P ∆V = -(0.857 atm) (-3.74 L) = 3.20 J
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The work done in the chemical reaction can be calculated using the formula W = P∆V, which gives the result as 292.1 Joules.
Explanation:Work done, especially in a process involving a gas, can be calculated when the pressure is constant and the volume changes. This is often referred to as pressure-volume work. In this particular case, we are given a process in a chemical reaction where the volume decreases from 5.00 to 1.26 L (a decrease of 3.74 L or 3.74 x 10^-3 m^3) against a constant pressure of 0.857 atm (which equals 0.857 x 1.01325 x 10^5 N/m^2). The formula to calculate work done is W = P∆V.
Inserting the given values into the formula, W = 0.857 x 1.01325 x 10^5 N/m^2 x 3.74 x 10^-3 m^3 which equals approximately 292.1 J (joules). Therefore the work involved in the chemical reaction is 292.1 J.
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Which of the following measurements represents the most matter?
A. 0.033 kg
B. 0.33 hg
C. 330 g
D. 3300 cg
Answer: C) 330 g
Explanation: Since all the masses are given in different units, it's good to make all of them to have same unit. Let's say we convert all of them to grams.
A) kg stands for kilogram and 1 kg = 1000 g
So, [tex]0.033kg(\frac{1000g}{1kg})[/tex]
= 33 g
B) hg stands for hactogram and 1 hg = 100 g
So, [tex]0.33hg(\frac{100g}{1hg})[/tex]
= 33 g
C) 330 g
D) cg stands for centigram and 1 cg = 0.01 g
So, [tex]3300cg(\frac{0.01g}{1cg})[/tex]
= 33 g
Looking at all the choices, choice A, B and D represent equal amount of matter that is 33 g where as choice C represents 330 g of matter.
Hence, the correct choice is C) 330 g.
The molar mass of sodium chloride is 58 g/mol. how many grams of sodium chloride are in 0.5 mol of sodium chloride?
Answer:
[tex]29 g. NaCl[/tex]
Explanation:
we know that it's molar mass is [tex]58 \frac{g}{mol}[/tex]
This means that 1 mol of sodium chloride contains 58g of sodium chloride; now How many grams of [tex]NaCl[/tex] are in 0.5 moles?
[tex]1 mol \longrightarrow 58g\\ 0.5 mol\longrightarrow x\\ x=\frac{0.5mol.58g}{1mol}=29g[/tex]
In 0.5 mol of NaCl there will be 29 g of sodium chloride