Explanation:
A scientific idea is an explanation for how something works, or the truth about some aspect of the world, that was figured out using the scientific process. ... Scientific ideas change over time as the evidence improves. The more experiments they do , and the more data they collect, the better the scientific ideas become.
a sample of element X contains 90% X-35 atoms,8.0%X-37 atoms, and 2.0% X-38 atoms. The average atomic mass will be closest to which value?
Answer:
35.2.
Explanation
R.A.M= Mass of isotopes divide by 100 percent
the density is 5.4 g/mL and the volume is 12.9 mL.
Answer:
69.66 g
Explanation:
We have the following from the question;
Density of the substance = 5.4 g/ml
Volume of substance = 12.9 ml
Mass of substance= the unknown
Since we have both density and volume of the substance, the question must be for us to obtain the mass of the substance, hence;
Density= mass/volume
Mass= Density × volume
Mass = 5.4 g/ml × 12.9 ml
Mass= 69.66 g
A student is worried about determining if a chemical is radioactive. Which
section of the SDS would the student refer to?
Product Information
Fire Fighting Methods
Physical and Chemical Properties
Hazards Identification
Answer:
Hazards Identification
Explanation:
A safety data sheet, SDS, is an informational document provided by the manufacturer or importer of a hazardous chemical detailing the chemical, physical, health, and environmental health hazards associated with the chemical as well as safety precautions in handling the chemical.
Some of the sections in the SDS include:
Product Information: It identifies the chemical as well as its recommended uses. The contact information of the manufacturer is also provided.
Fire fighting methods: It gives measures and guidelines necessary for fighting a fire caused by the chemical.
Physical and chemical properties: states the physical and chemical properties of the chemical substance such as: appearance, odor, pH, melting/freezing point, boiling point and boiling range, flammability, etc.
Hazards identification: states the hazards of the chemical and the necessary warnings regarding the hazards. Some of the information provided include: hazard classification of the chemical (for example flammable liquid, oxidizing gases,explosives, etc), signal word, hazard statement (for example radioactive), pictograms, precautionary statements, etc.
From the above information provided, the student should refer to the hazards identification section.
Please help...
Draw a diagram showing the bonding in:
a) Tetrachloromethane [CCI4]
Answer:
here u go! ................
Answer:
Hope this is ok :))
Explanation:
Answer in the correct significant figures: 35.6 + 56.27 *
Answer:
101.87
Explanation:
that's the answer
in h-atom if x is radius of first bohrs orbit de broglie wavelength of an atom in 3rd orbit is a.3πx b.6πx c.9x/2 d.x/2
please I need complete explanation fast
Answer:
can you type question properly.
2 Write the molecular formula of the compounds given below: Sodium hydrogen carbonate b) calcium hydroxide ) silver nitrate d) ammonium sulphate ) Magnesium carbonate f) Ferric oxidea
[tex]\\ \rm\Rrightarrow Sodium\:Hydrogen\:carbonate=NaHCO_3[/tex]
[tex]\\ \rm\Rrightarrow Calcium\:Hydroxide=Ca(OH)_2[/tex]
[tex]\\ \rm\Rrightarrow Silver\:Nitrate=Ag(NO_3)_2[/tex]
[tex]\\ \rm\Rrightarrow Ammonium\:Sulphate=(NH_4)_2SO_4[/tex]
[tex]\\ \rm\Rrightarrow Ferric\:oxide=Fe_2O_3[/tex]
differentiate between Physical and chemical changes
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
I HOPE THIS WILL HELP YOU IF NOT THEN SORRY HAVE A GREAT DAY:)Can someone plz help me :<
Answer: cats r alliens because they r kind of like ufos they would usually wonder around rather u know it or not when they spy on us it could b with us sleep cooking anything so they r like aliens
Explanation:
in the symbol 3p4
a. the 3 represents the principal energy level
b. the p represents the principal energy level
c. the 4 represents the principal energy level
d. all of the above
help!
Answer:
a. the 3 represents the principal energy level
Explanation:
3 is the principal energy level. The p is the sublevel. 4 is the possible occupying electron.
PLEASE HELP!! What direction do you predict the addition of a base to the solution containing bromophenol blue will drive the equilibrium? Explain your prediction in terms of Le Châtelier's principle.
Answer:
Below is the clarification of that same particular question.
Explanation:
Le Chatlier's theory states that whenever an equilibrium mechanism is disrupted by environmental influences, the program responds by changing the supplies information of its constituents in a somewhat way that the disturbance is invalidated and reaches a stable equilibrium during that disrupted stage, with concentrations of stability differently than ever before.Bromothymol blue seems to be a phenolic subs lone which always allows it to act throughout aqueous solutions as an acidic solution. Being such an acid (weak), it should not add to rapid, as well as introduces a balance with its accompanying but mostly disconnected form.For that kind of weak diprotic predictor, the standard economic statement can indeed be published as:
⇒ [tex]H_2In_(aq)\rightleftharpoons In^{2-} +2H^+[/tex]
It could be conclusively proven from either the theory of Le Charlier whereby, that whenever a strong acid becomes applied, the full disorientation of one or the other, through equilibrium formation, induces an increase throughout the medium's proton concentrations.Likewise, it absorbs the protons throughout the media to split water that whenever a solution is added. So, particle concentration throughout the medium is decreasing. To accommodate for this transition, the equilibrium reacts by moving to the correct i.e. causing further dissociation of the optimistic predictor into their dianion through protons, thereby attempting to nullify that perturbation.What evidence demonstrates that chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes?
Answer:
The evidence that demonstrated that the Chlorine in the stratosphere is believed to come primarily from CFCs ( Chlorofluorocarbons) rather than from natural sources such as volcanoes was due to the study conducted in which the amount of chlorine in the stratosphere over the past 20 years was measured and it was discovered that there was an increase over the years. This also corresponded with a rise in CFCs over the same period which shows that the chlorine in the stratosphere was from man made chemicals such as chlorofluorocarbons.
Chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes is evident as follows;
Discussion;
Most of the chlorine in the stratosphere is there as a result of human activities, as the figure below illustrates.
Many compounds containing chlorine are released at the ground.
Volcanoes can emit large quantities of hydrogen chloride, but this gas is rapidly converted to hydrochloric acid, which dissolves in rain water, ice, and snow and does not reach the stratosphere.
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What is the product of the reaction of pentanoic acid with ethanol in the presence of a strong acid?
Answer:
ethylpentanoate
Explanation:
Alkanoic acids react with alkanols in the presence of mineral acids to yield an ester and water. This is the organic analogue of the inorganic neutralization reaction. The reaction his commonly called esterification. It is an acid catalysed reaction.
The reaction of pentanoic acid and ethanol in the presence of a string acid is shown below;
CH3CH2CH2CH2COOH(aq) + CH3CH2OH(aq) ----> CH3CH2CH2CH2COOCH2CH3(aq) + H2O(l)
The name of the compound formed is ethylpentanoate.
What orbits around the nucleus
Answer:
Electrons orbit the nucleus.
Answer:
electrons
Explanation:Atoms are made up of protons and neutrons located within the nucleus, with electrons in orbitals surrounding the nucleus.
Which of the following pairs of compounds have the same empirical formula?
a. acetylene, C2H2, and benzene, C6H6
b. ethane, C2H6, and butane, C4H10
c. nitrogen dioxide, NO2, and dinitrogen tetroxide, N2O4
d. diphenyl ether, C12H10O, and phenol, C6H5OH
Answer:
option a and c both are correct
Explanation:
please mark me as brainliest
The pairs of compounds have the same empirical formula are:
a. acetylene, C₂H₂, and benzene, C₆H₆ and
c .nitrogen dioxide, NO₂, and di nitrogen tetroxide, N₂O₄
What is empirical formula?The empirical formula of a compound is defined as the formula that shows the ratio of elements present in the compound, but not the actual numbers of atoms found in the molecule.
In some cases, the empirical formula is the same as the molecular formula, which gives the actual number of atoms in a compound (e.g., H₂O).Otherwise, the molecular formula is a multiple of the empirical formula (e.g., CH₂O is the empirical formula for glucose, C₆H₁₂O₆).
Examples of empirical formulas:
Glucose has a molecular formula of C₆H₁₂O₆. It contains 2 moles of hydrogen for every mole of carbon and oxygen. The empirical formula for glucose is CH₂O.
The molecular formula of ribose is C₅H₁₀O₅, which can be reduced to the empirical formula CH₂O.
The pair with empirical formula is acetylene, C₂H₂, and benzene, C₆H₆ and
nitrogen dioxide, NO₂, and di nitrogen tetroxide, N₂O₄
Thus, option (A) and (C) are correct.
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Atoms contain positive and negative charges. Why is the overall charge on an atom neutral?
A. Atoms contain the same amount of protons and electrons, and their charges cancel out.
B. The nucleus of an atom contains neutrons, which keep the positive and negative charges balanced.
C. Atoms are all negatively charged because electrons are on the outside of the atom.
D. Atoms contain the same amount protons and neutrons, and their charges cancel out.
Answer:
Atoms contain the same amount protons and neutrons, and their charges cancel out.
Explanation:
Answer via Educere/ Founder's Education
Atoms contain positive and negative charges, the overall charge on an atom neutral because Atoms contain the same amount of protons and electrons, and their charges cancel out.Hence, Option (A) is correct
What is an Atom ?
An atom is the smallest unit of ordinary matter that forms a chemical element.
Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms.
Atoms are extremely small, typically around 100 picometers across.
An atom consists of a positively charged nucleus, surrounded by one or more negatively charged particles called electrons.
The positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral.Hence, Option (A) is correct
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A sample of gas has a volume of 20 cm³.The pressure is changed to 90 kPa at constant temperature,while the volume increases to 75 cm³.What was the original pressure of the gas?
Answer:
337.5kPa ~ 338kPa
Explanation:
Using the ideal gas law PV=nRT we have the following definitions from the problem:
V(initial) = 20cm³
P(initial) = ?kPa
V(final) = 75cm³
P(final) = 90kPa
Since we know that the number of moles of the sample did not change, nor did the temperature, nor does the ideal gas constant (R) we can rewrite this equation to state:
P(initial)V(initial) = nRT =P(final)V(final) ~ P(initial)V(initial) = P(final)V(final)
Rearranging this equation as we are solving for the initial pressure we find that:
P(initial) = (P(final)V(final))/V(initial)
P(initial) = ((90kPa)(75cm³))/20cm³
P(initial) = 337.5kPa ~ 338kPA
HELP URGENT PLS!1!! In what direction and how many spaces must you move the decimal point to make the following conversion?
600 L to mL
left; 6 spaces
left; 6 spaces
left; 3 spaces
left; 3 spaces
right; 6 spaces
right; 6 spaces
right; 3 spaces
To convert from L to ml, we move three spaces to the right and the decimal place moves three places.
Our task here is to convert 600 L to mL. we have to remember that to convert from L to ml, we have to multiply the value in L by 1000
In other words, the value 1000 is known as the conversion factor.
When we do this, we move the decimal place three places to the right to have 600000.00mL
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Can a window pane be considered a mineral?
Answer:
Explanation:
The glass (which does not crystallize even though it is accepted) of a window is NOT a mineral, since it is neither a substance of natural origin (although it is manufactured from natural components) nor does it have a defined crystalline structure, that is, the atoms they are not arranged in an orderly and regular way along axes and planes forming flat faces that keep a symmetry.
Remember that a mineral is defined as a solid, inorganic, homogeneous substance, of natural origin, with a crystalline structure and a determined and well-defined chemical composition within narrow margins and that has regular and characteristic physical properties.
Explanation: No, glass is not a mineral. ... Definable chemical composition: SiO2 *Actually, most industrially-produced glass is not pure silica, but having impurities is still a definable chemical composition so this part of the definition is ok. Orderly arrangement of atoms in a lattice: NO.
7.95x10 converted to the number is
7.95 × 10
= 79.5
This is the answer
Question number 4..
Answer:
I think it's 7089 because that's my answer to your questions
In a reversible reaction, the endothermic reaction absorbs ____________ the exothermic reaction releases.
A. None of these, endothermic reactions release energy
B. more energy than
C. the same amount of energy as
D. less energy than
Answer:
C. the same amount of energy as
Explanation:
Firstly, a chemical reaction can either absorb energy from its surroundings to occur or release energy into its surroundings as a product. The former and latter descriptions are called ENDOTHERMIC and EXOTHERMIC reactions respectively. An exothermic reaction is that which transfers energy, in form of heat, to its surroundings while an Endothermic reaction is that which absorbs energy (heat) from its surroundings.
However, a reversible reaction is that reaction in which the formation of products from reactants and reformation of the reactants from products occur simultaneously. Hence, the products of a reversible reaction can become the reactants and move in the opposite direction. For example:
Reversible reaction: A + B ⇆ C + D means;
A + B → C + D and;
C + D → A + B
In a case whereby the opposite reactions consist of an endothermic and exothermic reactions, the endothermic reaction absorbs the same amount of energy as the exothermic reaction releases.
According to the law of conservation of energy, no energy is lost during a reversible reaction. Hence, in order to achieve an equilibrium, the amount of energy absorbed by the endothermic reaction is the same as the amount of energy released in the opposite exothermic reaction.
Use Charles's Law to solve the following problem. A sample of air has a volume of 550.0 mL at 106 °C. At what temperature will its volume be 700.0 mL at constant pressure?
a
482 K
b
63 °C
c
505 K
d
119 °C
Answer:
im not sure but i think its c
505 K
Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below. A purple ball in the center surrounded by overlapping concentric black ovals, each with a small green ball on each of the 6 ovals. What experimental evidence led to the development of this atomic model from the one before it? A few of the positive particles aimed at a gold foil seemed to bounce back. The colors of light emitted from heated atoms had very specific energies. Experiments with water vapor showed that elements combine in specific proportions. Cathode rays were bent in the same way whenever a magnet was brought near them.
Answer:
A few of the positive particles aimed at a gold foil seemed to bounce back.
Explanation:
Rutherford's experiment took the search for the structure of the atom a step further. In this experiment, a narrow beam of alpha particles emitted from a source was used to bombard a thin gold foil.
The scattering of the alpha particles was detected by a movable ZnS screen. It was found that most of the alpha particles followed a straight path through the gold foil but some were scattered through large angles and some even scattered backwards.
Following this experiment, Rutherford decided on his planetary model of the atom in which the nucleus is at the core of the atom with electrons moving round the nucleus in orbits. Rutherford was awarded a Nobel prize for this work.
Answer:
a
Explanation:
edge 2020
You are given two aqueous solutions with different ionic solutes (Solution A and Solution B). What if you are told that Solution A has a greater concentration than Solution B by mass percent, but Solution B has a greater concentration than Solution A in terms of molality? Is this possible? If not, explain why not. If it is possible, provide example solutes for A and B and justify your answer with calculations.
Answer:
Yes, it is possible. Let us consider an example of two solutions, that is, solution A having 20 percent mass RbCl (rubidium chloride) and solution B is having 15 percent by mass NaCl or sodium chloride.
It is found that solution A is having more concentration in comparison to solution B in terms of mass percent. The formula for mass percent is,
% by mass = mass of solute/mass of solution * 100
Now the formula for molality is,
Molality = weight of solute/molecular weight of solute * 1000/ weight of solvent in grams
Now molality of solution A is,
m = 20/121 * 1000/80 (molecular weight of RbCl is 121 grams per mole)
m = 2.07
Now the molality of solution B is,
m = 15/58.5 * 1000/85
m = 3.02
Therefore, in terms of molality, the solution B is having greater concentration (3.02) in comparison to solution A (2.07).
If an atom has three shell and number of valence electrons are two. Is this element metal
or non-metal and why? Name the element and it’s valency.
Answer:
Metal
Element: Calcium
Valency: 2
Explanation:
To find the element, let's use the periodic table. (Look below)
We already went past 3 shells, just need the 2 electrons after it.
Just skip to the 4th row and count 2 to the right
We end up at Calcium.
Calcium is a metal and we're also on the alkaline earth metals column.
Calcium will need to lose 2 electrons to reach stability, so the valency is 2.
What type of Nuclear decay is shown by the reaction below
Answer:
bete is your answer.
have a great day.
I think c ....is write answers
Calculate the heat when 100.0 mL of 0.500 M HCl is mixed with 300.0 mL of 0.100 M Ba(OH)2. Assuming that the temperature of both solutions was initially 25.0C and that the final mixture has a mass of 400.0 g and a specific heat capacity of 4.18 J/C g, calculate the final temperature of the mixture.
Answer:
26.8°C
Explanation:
For this reaction, the equation can be computed as follows:
[tex]2HCl_{(aq)}+ Ba (OH)_{2(aq)} \to BaCl_{2(aq)} + 2H_2O_{(l)} \ \ \ \ \ \ \Delta H= -118 \ kJ[/tex]
Now, Given that:
100.0 mL of 0.500 molarity (M) of HCl reacted with 300.0 mL of 0.100 molarity of Ba(OH)2.
The next process is to determine the number of moles of the solute:
For HCl:
no of mole = [tex]\dfrac{0.500 \times 100}{1000}[/tex]
= 0.05 mol
For Ba(OH)2:
no of mole =[tex]\dfrac{0.100\times 300}{1000}[/tex]
= 0.03 mol
From the reaction, at the reactant side, we will see that two moles of HCl reacted with one mole of Ba(OH)2.
It implies that HCl is the limiting agent since it is in lesser quantity.
Similarly, the heat given out of the system is 118 kJ for each two moles of HCl with one mole of B(OH)2.
Hence, for 0.05 moles of HCl, the heat emitted out is:
[tex]= 0.05 mole \times ( \dfrac{118 \ kJ}{2 \mol})[/tex]
= 2.95 kJ
Let's recall from the question that:
the heat emitted was moved to the final mixture with mass =400g
the specific heat capacity = 4.18 J/°C g
Initial temperature = 25°C
∴
Using the formula;
ΔH = mass × specific heat capacity × (T_f - T_i)
Then, replacing the values, we have:
2.95 kJ = 400 g × 4.18 J/°C g × ( T_f - 25° C)
2950 J = 400 × 4.18 J/°C × ( T_f - 25° C)
[tex]T_f = \dfrac{2950 \ J}{400 \times 4.18 \ J/^0 C}+25^0\ C[/tex]
[tex]\mathbf{ T_f = 26.8^0 \ C}[/tex]
What are the standard temperature and pressure conditions enthalpy is usually measured under
Answer:
temperature must be 273 Kelvin (0°C)
pressure must be 1 atm
describe an activity to separate the mixture of sand and water
Answer:
Sedimentation and decantation
Explanation:
Sedimentation and decantation: Mixture is kept undisturbed for some time. After some time, sand being heavier and insoluble in water, settles down at the bottom of container. Now, water is poured into another container to separate it from sand.
Answer:
evaporation or destillation
Explanation:
When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation.