express in scientific notation (6.0x10^4) (3.1x10^-1)
The Answer is: 1.86×10^4
Answer:
1.86 x 104
Explanation:
This mathematical operation is a multiplication, so:
1.- Multiply the number as usual: 6 x 3.1 = 18.6
2.- Multiply the coefficients, remember since they coefficients, a multiplication, actually you need to add them: 4 + (-1) = 3+
3.- Then you write the number with the coefficient: 18.6 x 103
4.- In this case since the scientific notation just admit one number will be:
1.86 x 104
Which of the following represents radiant energy being converted to chemical energy?
a. A plant uses energy from the sun to make sugar stored in fruit.
b. A slingshot is used to shoot a rock across the room.
c. A lamp lights up after it is plugged into an outlet in the wall.
d. A rock sitting at the top of a hill is pushed down the hill.
help me nowww please and thanks
The answer to your question is Gallium, or GA. The trick is to always check if they are along the same vertical column. This indicates that they have the same Valence electrons, which is involved in all the bonding and define the electronegative status of the atom.
Remark
I can't understand why this was reported. It's a perfectly straight forward question, unless someone recognized it as part of a test.
I know that the answer is supposed to be Ga, but in many ways Boron resembles Carbon than it does Ga. Be that as it may, the answer you want is Ga.
Cathy conducts a scientific investigation. How can she make sure her results are valid? A. repeat the investigation several times B. confirm that her results match her hypothesis C. write a report about her results D. use metric measuring units during her investigation Pls Help Me....... It's Science By the way.
A. repeat the investigation several times. You must repeat an experiment to make sure it is valid.
Answer:
the answer is A
Explanation:
How does chromatography separate substances
Chromatography is actually a way of separating out a mixture of chemicals, which are in gas or liquid form, by letting them creep slowly past another substance, which is typically a liquid or solid. ... As the mobile phase moves, it separates out into its components on the stationary phase
Answer:
Chromatography is really a method for isolating out a blend of synthetics, which are in gas or fluid shape, by giving them a chance to crawl gradually past another substance, which is regularly a fluid or strong.
Explanation:
Chromatography can be utilized to isolate blends of hued mixes. Blends that are reasonable for division by chromatography incorporate inks, colors and shading operators in nourishment. Basic chromatography is completed on paper. ... Diverse parts of the blend will move at various rates.There are four primary sorts of chromatography. These are Liquid Chromatography, Gas Chromatography, Thin-Layer Chromatography and Paper Chromatography. Fluid Chromatography is utilized on the planet to test water tests to search for contamination in lakes and waterways.
An atom’s lewis dot structure has two dots, which element could it be, and why?
Final answer:
An atom's Lewis dot structure with two dots indicates that it is Helium (He), which has two valence electrons in its outermost shell, achieving a stable electronic arrangement and typically not forming chemical bonds.
Explanation:
An atom’s Lewis dot structure with two dots indicates it has two valence electrons. The element that fits this description is Helium (He). The number of dots around an element's Lewis symbol represents its valence electrons, which are crucial for forming chemical bonds. Helium's electron configuration is 1s2, meaning it has two electrons in its outermost shell, both of which are depicted as dots in its Lewis dot structure. This structure is a visually simple method to represent valence electrons and predict bonding behavior. Helium, with its two valence electrons completely filling its first and only energy level, achieves a stable electronic arrangement, thus typically does not form chemical bonds with other elements.
Final answer:
An atom's Lewis dot structure with two dots likely represents helium (He), as the number of dots indicates valence electrons, and helium has two valence electrons, completing its outer shell.
Explanation:
An atom's Lewis dot structure with two dots could represent the element helium (He). This is because the number of dots in a Lewis dot structure indicates the number of valence electrons an atom has. Helium is in Group 18 of the periodic table, which is known as the noble gases. These elements are characterized by having a full outer shell of electrons. For helium, which is in the first period of the periodic table, having two valence electrons fills its outer shell, as it only has one shell. Therefore, its Lewis dot structure is represented with two dots, signifying its two valence electrons.
Which equation represents the reaction of a weak acid with water?
A.
HCl + H2O H3O+ + Cl-
B.
HCO3– + H2O H2CO3 + OH–
C.
H2O H + + OH-
D.
HCOOH + H2O H3O+ + HCOO-
Answer: The correct answer is Option D.
Explanation:
Weak acid is defined as the acid which does not completely dissociates into its ion when dissolved in water.
For the given options:
Option A: [tex]HCl+H_2O\rightarrow H_3O^++Cl^-[/tex]
HCl is a strong acid because it completely looses its proton when dissolved in water.
Option B: [tex]HCO_3^-+H_2O\rightarrow H_2CO_3+OH^-[/tex]
Hydrogen carbonate ion is a base because it is easily accepting a proton from water.
Option C: [tex]H_2O\rightarrow H^++OH^-[/tex]
The above equation represents the ionization of water.
Option D: [tex]HCOOH+H_2O\rightarrow H_3O^++HCOO^-[/tex]
Formic acid is considered as a weak acid because it does not completely dissociates into its ions when dissolved in water.
From the above information, the correct answer is Option D.
The burning of the magnesium becomes uncontrolled (it burns brightly). oops! will the reported mole ratio of magnesium to oxygen be too high or too low as a result of this technique error? explain.
Answer:
The answer is Less oxidation will happen while its consuming, so the proportion to O² to magnesium would be substantially higher than common.
Explanation:
At the point when decrease happens, a component picks up electrons and its oxidation number declines or is diminished. To decide whether a red ox response has happened and to distinguish the component oxidized and the component decreased: Assign oxidation numbers to all iotas in the equation.In ionic and free extreme responses, oxidation and decrease are characterized as procedures by which a component experiences a net misfortune or gain of electrons, separately. ... In reference to natural particles, oxidation is a procedure by which a carbon iota picks up bonds to more electromotive components, most usually oxygen.
Uncontrolled burning of magnesium leads to more oxygen being consumed than that needed for a perfect stoichiometric reaction. Hence, this would result in the mole ratio of magnesium to oxygen to be reported lower than it would be if the magnesium burning was controlled. The reaction with other substances like nitrogen or carbon dioxide can also influence the mole ratio.
Explanation:If magnesium burns uncontrolled, it will consume more oxygen than required for the stoichiometric reaction with magnesium. As a result, the mole ratio of magnesium to oxygen will be reported lower than it actually is. In the reaction 2Mg(s) + O2(g) → 2MgO(s), one mole of oxygen reacts with two moles of magnesium. However, if magnesium burns uncontrollably, it will react with more than the required amount of oxygen.
Thus, an abundance of oxygen implies a decrease in the mole ratio of magnesium to oxygen. Apart from this, an uncontrollable burning of magnesium might lead to its reaction with nitrogen or carbon dioxide, which can further lower the reported mole ratio of magnesium to oxygen.
Learn more about Mole ratio magnesium to oxygen here:https://brainly.com/question/26652938
#SPJ3
Sodium carbonate is often used in certain candies to create fizzy bubbles when solid weak acids in the candy are dissolved with saliva. Explain the fizzing effect.
Answer is: in chemical reaction with with weak acid, sodium carbonate produce carbonic acid (H₂CO₃), which decomposes into carbon(IV) oxide (fizzy bubbles) and water.
Balanced chemical reaction:
Na₂CO₃ + 2HClO → CO₂(g) + H₂O + 2NaClO.
Chemical decomposition is the separation of a carbonic acid into water and carbon dioxide: H₂CO₃ → CO₂ + H₂O.
Chemical properties
a) Can be observed without altering the identity of a substance
b). include mass and color
c) Include changes that alter the identity of a substance
d) Include changes of state of a substance
plz explain why too so i can actually learn it!!
Chemical properties include characteristics that describe how a substance changes its chemical structure or composition, as in the case of flammability. The correct answer is c) Include changes that alter the identity of a substance, because chemical properties lead to chemical changes, which result in new substances with different identities.
The chemical properties of a substance refer to the characteristics that describe its ability to undergo specific chemical changes that alter its identity. For instance, the flammability of a substance is a chemical property because when a substance burns, it produces new substances with different chemical compositions. Observing a chemical property involves causing a chemical change.
a) Can be observed without altering the identity of a substance: This statement describes a physical property, not a chemical property.
b) Include mass and color: These are examples of physical properties, not chemical properties.
c) Include changes that alter the identity of a substance: This statement correctly defines a chemical property.
d) Include changes of state of a substance: Changes of state, such as melting or freezing, are physical changes, not chemical changes.
Therefore, the correct answer is c) Include changes that alter the identity of a substance, because chemical properties involve changes in the chemical structure or composition of a substance, such as its reaction to form new substances.
Question 1 (True/False Worth 4 points) (03.06 LC) An instantaneous dipole occurs when a molecule's moving electrons are briefly more concentrated in one place than another, causing the molecule to become temporarily polarized.
True False
Question 2(Multiple Choice Worth 4 points) (03.06 LC) What type of intermolecular force occurs between all substances?
Covalent bonding
Hydrogen bonding
Ion-dipole force
London dispersion force
Question 3(Multiple Choice Worth 4 points) (03.06 MC) When comparing H2, NH3, O2, and CH4, which of the following statements is correct?
CH4 has the highest boiling point because it experiences dipole-dipole forces.
H2 has the strongest intermolecular forces because it has the lowest mass. NH3 has the highest boiling point because it experiences hydrogen bonding.
O2 has the strongest intermolecular force because it experiences London dispersion forces.
Question 4(Multiple Choice Worth 4 points) (03.06 MC)
The boiling points of diatomic halogens are compared in the table.
Boiling Points of Diatomic Halogens Molecule Boiling Point
F2 −188 °C
Cl2 −34 °C
Br2 59 °C
I2 184 °C
Which of the following statements best explains the trends in boiling points?
The atomic size increases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
The chances of forming a permanent dipole increase down the group and this increases the strength of the intermolecular forces.
Question 5(Multiple Choice Worth 4 points) (03.06 MC) What is the strongest intermolecular force that occurs between molecules of CO2?
Dipole-dipole
Induced dipoles
Ionic bonding
London dispersion
PLEASE HELP ASAP 30 POINTS...WILL MARK BRAINLIEST
Answer:
The correct answers are (1) True (2) London dispersion force (3) one of the option is missing, none of these three is an answer (4) The total number of electrons increases down the group, and this increases the strength of the intermolecular forces (5) London dispersion forces which are always present.
Explanation:
Given: An instantaneous dipole occurs when a molecule's moving electrons are briefly more concentrated in one place than another, causing the molecule to become temporarily polarized.
Answer: True
when the electrons moving in a molecule or an atom move towards one end of the molecule or atom the other end has a small positive pole at that time and the end where electrons move has a small negative pole. So, a dipole is formed for that instant.
(2) What type of intermolecular force occurs between all substances?
Answer: London dispersion force
remember from first part how an instantaneous dipole is formed. When a pole is formed at that instant the molecule in neighborhood can interact with the dipole that was formed. The dipole that was formed has a positive pole and a negative pole. If the neighboring molecule is present near positive pole it’s electrons will get attracted to the positive pole of the dipole. This interaction is called London dispersion force. Since every atom or molecule or ion in the universe has electrons, so there is development of instantaneous dipole in each of them and each one of them has London dispersion force acting on them.
(3) When comparing [tex]H_2,\;NH_3,\;O_2,\; \rm{and}\;{CH_4[/tex] which of the following statements is correct?
Answer: one of the option is missing, none of these three is an answer.
(4)The boiling points of diatomic halogens are compared in the table.
Answer: The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
(5) What is the strongest intermolecular force that occurs between molecules of [tex]CO_2[/tex]?
Answer: London dispersion forces which are always present.
London forces are weakest forces, if other forces would have been present then we would have ignored London forces but since no other forces are present, the only choice is London forces.
[tex]CO_2[/tex] is a non polar molecule, it does not have permanent dipole moment. So there are no chances of dipole-dipole, [tex]CO_2[/tex] doesn’t have a positive or negative charge so even not ionic bond.
Learn more about dipole here:
https://brainly.com/question/18382778?referrer=searchResults
Which molecules shown on the graph above are likely candidates for evaporation?
1. molecules under the left end of the curve
2. molecules under the apex of the curve
3. molecules under the right end of the curve
4. all molecules under curve "T2"
Answer : The correct option is, (3) molecules under the right end of the curve
Explanation :
Evaporation : It is type of process in which the phase changes from liquid state to gaseous state below the boiling temperature of the liquid.
As we know that the higher the temperature of the liquid [tex](T_2)[/tex], the more will be the molecule escaping into the gaseous phase than the lower temperature [tex](T_1)[/tex].
So, the molecules under the right end of the curve are likely candidates for evaporation.
Hence, the correct option is, (3)
Answer: molecules under the right end of the curve
Explanation: smart
Which statement correctly describes how sound energy is transferred when a whale makes a sound underwater? A. Water particles are not squeezed together or pulled farther apart. B. Water particles are squeezed together but not pulled farther part. C. Water particles are squeezed together and pulled farther apart. D. Water particles are pulled farther apart but not squeezed together.
I think the answer is B because Sound travels about 1,500 m/s underwater, and sound travels about 332 m/s in air. Sound underwater travels faster and longer in water. The particles are more tightly packed together, so sounds travel faster through water.
Classify the properties based on whether they describe metals or nonmetals. They are good conductors of heat and electricity. They are brittle and break into sharp pieces. They are flexible and can be made into wires. They are mostly solids at room temperature. They are poor conductors of heat and electricity. They are solids, liquids, or gases at room temperature. Reset Next
Classified based on the properties of metals
They are good conductors of heat and electricityThey are mostly solids at room temperatureThey are flexible and can be made into wiresClassified based on the properties of nonmetals.
They are brittle and break into sharp piecesThey are poor conductors of heat and electricityThey are solids, liquids, or gases at room temperatureWhat are metals and non-metals?Metals are opaque, lustrous elements that are good conductors of heat and electricity. Most metals are malleable and ductile and are, in general, denser than the other elemental substances.The metals of antiquity are the seven metals that humans had identified and found use for in prehistoric times: gold, silver, copper, tin, lead, iron, and mercury.Aluminum, cadmium, chromium, copper, iron, lead, nickel, tin, zinc, or any combination of these elements are considered common metals.Non-metals are natural materials that do not produce heat or electricity and that are structurally brittle (can not be easily rolled, molded, extruding, or pressed). Hydrogen, carbon, nitrogen, oxygen, phosphorus, arsenic, and selenium are the non-metallic elements in the periodic table.To learn more about metals and nonmetals refer:https://brainly.com/subject/chemistry
#SPJ2
Answer: I just took the test and it was right!
Explanation:
Electron A falls from energy level X to energy level Y and releases blue light. Electron B falls from energy level Y to energy level Z and releases red light. Which transition, from X to Y or from Y to Z, has a greater energy difference? Explain your answer and how you arrived at it. Use a diagram of the electromagnetic spectrum.
Answer: Transition from X to Y will have greater energy difference.
Explanation: For studying the energy difference, we require Planck's equation.
[tex]E=\frac{hc}{\lambda}[/tex]
where, h = Planck's Constant
c = Speed of light
E = Energy
[tex]\lambda[/tex] = Wavelength of particle
From the equation, it is visible that the energy and wavelength follow inverse relation which means that with low wavelength value, energy will be the highest and vice-versa.
As electron A falls from X-energy level to Y-energy level, it releases blue light which has low wavelength value (around 470 nm) which means that it has high energy.
Similarly, Electron B releases red light when it falls from Y-energy level to Z-energy level, which has high wavelength value (around 700 nm), giving it a low energy value.
Energy Difference between X-energy level and Y-energy level will be more.
7.602x1024 atoms of lead has a mass of ____________ grams.
(Enter just the number for this one.)
Hello!
To find the mass of 7.602 x 10^24 atoms of lead, we need to find the number of moles first, then we will be able to find the mass. To find the moles, we need to divide the total number of atoms by Avogadro's number, which is 6.02 x 10^23. Also, one mole of lead is equal to it's atomic mass, which is 207.2 grams.
1). Find the number of moles
(7.602 x 10^24) / (6.02 x 10^23) ≈ 12.62790
Using significant figures, there are 12.8 moles of lead.
2). Find the mass of lead
12.8 moles x 207.2 grams = 2652.16 grams
Using significant figures, the mass of the given amount of lead is 2650 grams. (Exact value is 2652.16 grams).
How do the major and minor scale divisions relate the precision of measurements taken with a metric ruler or graduated cylinder?
Answer: Major scale and minor scale both relate the precision of measurements with more true value of measurement.
Explanation:
Major scale in a measuring device is maximum unit value on the scale that can be measured.
Minor scale in a measuring device is a least unit value on the scale that can be measured.
In a metric ruler major scale is 1 cm and minor scale is 0.1 mm which means one can measure accurate value up-to one decimal point and in 10 ml of graduated cylinder major scale division is 1 ml minor scale division is 0.01.
On a potential energy diagram, what is true about activation energy?
Activation energy is the same for both endothermic and exothermic reactions.
Activation energy is greater for endothermic reactions.
Activation energy is greater for exothermic reactions.
Activation energy is represented by a negative slope.
Why hello there!
The correct answer to your question is C because exothermic energy is based of on using heat and heat acts like the activation !
If my answer helped please mark me as brainliest i really want to rank up thank you and have the best day ever!
Answer:
I think the answer is B
suppose that 0.05 g of NaHCO3 reacts with 0.05 g of HCI and the reaction bubbles due to the carbon dioxide being produced. if the substance produced are 0.04 g water and 0.03g of salt how many grams if carbon dioxide gas were produced
The balanced chemical equation for the given reaction:
NaHCO₃ + HCl --> NaCl + H₂O + CO₂
Given, mass of NaHCO₃ = 0.05 g
Molar mass of NaHCO₃ = 84.007 g/mol
Moles = mass/molar mass
Moles of NaHCO₃ = 0.05 g/84.007 g/mol
Moles of NaHCO₃ = 6.0 x 10⁻⁴
Given, mass of HCl = 0.05 g
Molar mass of HCl = 36.46 g/mol
Moles of HCl = 0.05 g/ 36.46 g/mol
Moles of HCl = 1.4 x 10⁻³
Since NaHCO3 has the least number of moles, it is the limiting reagent.
As per the balanced equation the molar ratio between NaHCO₃ : CO₂ is 1:1
Therefore, moles of CO₂ = 6.0 x 10⁻⁴
Molar mass of CO₂ = 44 g/mol
Mass = moles x molar mass
Mass of CO₂ = 6.0 x 10⁻⁴ mol x 44 g/mol = 0.0264 g
Mass of carbon dioxide gas produced = 0.0264 g
The Earth's biosphere is consists of A. The part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life. B. Only the water on Earth that is in its solid form. C. The solid part of the earth consisting of the crust and outer mantle. D. All of the Earth's water, including surface water, groundwater, snowcover, ice, and water in the atmosphere.
Answer:
The answer is A: the part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life.
Explanation:
i got it on study island and make sure you copy this "the part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life." and do ctrl f and paste and check where your answer is because the answer might be shuffled hope you have a great day!! :)
The part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life. Thus option A is correct.
What are the composition of atmosphere ?The atmosphere is a gas that cover the a planet and is present in place by the gravitational force of the planet, the temperature of the atmosphere is low.
The atmosphere is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases, variable amount of water vapor are also present .
Carbon dioxide gas is responsible mainly for the greenhouse effect, transparent to the incoming solar radiation but is opaque to the outgoing terrestrial radiation.
Dust particles are present in the atmosphere, these particles act as hygroscopic nuclei around which water vapor condenses to produce clouds.
Thus option A is correct.
Learn more about atmosphere, here:
https://brainly.com/question/15882185
#SPJ2
How many hydrogen atoms are in 6.90 mol of ammonium sulfide?
(NH4)2S this is chemcial formula of ammonium sulfide
in 1 mole of ammonium sulfide there are 4*2 = 8 moles of H atoms are present
but in 0.69 moles of ammonium sulfide = 8 * 0.69 = calculate it
Answer : The number of atoms of hydrogen are [tex]3.32\times 10^{25}[/tex]
Explanation : Given,
Moles of ammonium sulfide = 6.90 moles
The chemical formula of ammonium sulfide is, [tex](NH_4)_2S[/tex]
In ammonium sulfide, there are 2 atoms of nitrogen, 8 atoms of hydrogen and 1 atom of sulfur.
As we know that,
1 mole of substance always contains [tex]6.022\times 10^{23}[/tex] number of atoms.
As, 1 mole of ammonium sulfide contains [tex]8\times 6.022\times 10^{23}[/tex] number of hydrogen atoms
So, 6.90 mole of ammonium sulfide contains [tex]6.90\times 8\times 6.022\times 10^{23}=3.32\times 10^{25}[/tex] number of hydrogen atoms.
Therefore, the number of atoms of hydrogen are [tex]3.32\times 10^{25}[/tex]
A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
Substance Density (g/cm3) Melting Point (°C) Boiling Point (°C)
molybdenum 10.28 2,623 4,639
mercury 13.53 -39 357
hafnium 13.31 2,233 4,603
lead 11.34 327 1,749
A.
molybdenum
B.
mercury
C.
hafnium
D.
lead
Answer:- C. Hafnium.
Solution:- Mass of the sample is 46.0 g and it's volume is [tex]3.5cm^3[/tex] .
From mass and volume, we can calculate it's density using the formula:
[tex]density=\frac{mass}{volume}[/tex]
[tex]density=\frac{46.9g}{3.5cm^3}[/tex]
[tex]density=\frac{13.4g}{cm^3}[/tex]
On the basis of the density, this substance could either be mercury or hafnium. Since the substance is a solid at room temperature where as mercury is liquid. So, it can't be mercury.
The right choice is C) Hafnium.
Answer:
the one above me
Explanation:
1. Define fission and fusion. Give an example of fission and fusion reflecting in real life application.
Answer :
Nuclear fission : In nuclear reaction, the nucleus of a larger atom breaks into two or more smaller nuclei. In fission process, protons and neutrons are produced and larger amount of energy is released.Example : In nuclear power plant, the energy released from the process of nuclear fission which is converted into electrical energy that is used in our homes and factories.
Nuclear fusion : In nuclear reaction, the nuclei of two or more smaller atoms combine together to form single larger molecule. In fusion process, the mass of the resulting nuclei is more as compared to the starting nuclei and large amount of energy is also released.Example : This process occurs in the sun and stars. In this, the isotopes of Hydrogen, Tritium and Deuterium combine together to form a neutron and a helium atom under high pressure and temperature.
help please chemistry question
Answer:
D. [tex]K_{a} = \frac{[\text{H}^{+}][\text{NO}_{2}^{-}]}{[\text{HNO}_{2}]}[/tex]
Explanation:
The general form of an equilibrium constant expression is
[tex]K = \frac{[\text{Products}]}{[\text{Reactants}]}[/tex]
In the equilibrium
HNO₂ ⇌ H⁺ + NO₂⁻
The products are H⁺ and NO₂⁻, and the reactant is HNO₂.
∴ [tex]K_{a} = \frac{[\text{H}^{+}][\text{NO}_{2}^{-}]}{[\text{HNO}_{2}]}[/tex]
An unknown substance has hydrogen ion concentration of [H+]=3.1*10^-8M. Find the pH and classify the substance as acidic or basic
pH = 7.51. The substance is basic.
[H⁺] = 3.1 × 10⁻⁸ mol·L⁻¹.
pH = -log[H⁺] = -log(3.1 × 10⁻⁸) = 7.51
The substance is basic because pH > 7.
Final answer:
The pH of the substance with a hydrogen ion concentration of 3.1*10^-8M is 7.51, indicating that the solution is basic.
Explanation:
The pH of a substance can be calculated using the formula pH = -log[H+], where [H+] is the concentration of hydrogen ions in moles per liter (M). Given that the hydrogen ion concentration of the unknown substance is [H+]=3.1*10^-8M, we can calculate the pH as follows:
pH = -log(3.1*10^-8)
pH = 7.51
As the pH is higher than 7, the substance is classified as basic.
A board has a mass of 750 g. If you ground the whole board down to sawdust, what would be the mass of the pile of sawdust?
The law of conservation of mass states that mass can neither be created nor destroyed. For example in an isolated system, mass of the reactants is equal to the mass of the products. Thus, mass or the quantity of the system under consideration will remain unchanged through any physical or chemical process.
In the given example, the board initially has a mass of 750 g. It is physical transformed to sawdust by grinding. Based on the conservation of mass, the pile of sawdust would still weigh 750 g.
How many valence electrons are in an atom of strontium (Sr)? Consult the periodic table. A. 5 B. 2 C. 47.90 D. 22
The smallest and the basic particle of a chemical element is said to be an atom. It is made up of three subatomic particles that is electrons, protons and neutrons. The neutrons and protons are present in the nucleus of an atom whereas electrons are present in the orbits around the nucleus of the atom. There are several shells in the orbital depending on the atomic number. The electrons which are present in the outermost shell are said to be valence electrons.
They can be determined by the electronic configuration of the element.
The atomic number of strontium, [tex]Sr[/tex] is 38. The electronic configuration of strontium, [tex]Sr[/tex] is:
[tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}[/tex]
From the electronic configuration it is clear that the outermost shell of strontium, [tex]Sr[/tex] is [tex]5s[/tex]. So, the number of valence electrons in strontium, [tex]Sr[/tex] is 2.
Hence, there are 2 valence electrons in an atom of strontium ([tex]Sr[/tex]).
The number of valence electrons are in an atom of strontium (Sr) is 2 and the correct option is option B.
Atomic number is the number of protons present in the nucleus of an atom. It is always equal to the number of electrons in orbit about that nucleus (in a nonionized atom). Thus, all atoms that have the same number of protons--the atomic number--are atoms of the same element.
The modern periodic table is arranged in such a way that all the elements have an increasing atomic number, and subsequently, increasing mass number.
Learn more about Atomic number, here:
https://brainly.com/question/16858932
#SPJ1
Identify three areas of energy research that scientists are working on today.
Answer:
wind, solar, bioproduction
Explanation:
The wind energy, since in some places the wind reaches fast velocities, the scientist try to implement new technology to improve how to convert wind energy in electricity for example.
The solar energy, even we have by now the solar panels, there is still an area to research to obtain again the mayor quantity of energy with less materials.
The bioproduction, since the mammals we produce liquid and solid wastes, how to convert it into energy like gas, electricity, etc.
Without what do carbohydrates fats and proteins can not be changed into energy
vitamins is the answer to your question
A substance did not change its chemical nature in a reaction. Which most likely describes the reaction?
A)It was heated.
B)It was hit with a hammer.
C)It was placed in a salt solution.
D)It was frozen.
The answer is D. It was frozen.
This is because freezing an object doesn't change chemical properties, only change the state of the matter.