Answer:
Overall charge = -3
Explanation:
The atom of every chemical element is its smallest indivisible part. However, this atom further consists of subatomic particles namely: proton, electron, and neutron. The proton and electron are the positively charged and negatively charged particle respectively.
In a neutral atom, the amount of proton and electrons in that atom equates. However, the amount of electron and proton present in an atom determines the charge of that atom. For example, in this question, an atom is said to contain 17 protons, 17 neutrons and 20 electrons.
Since the negatively charged electrons (20) are more than the positively charged protons (17) by 3, hence, the net charge is -3.
The numbers represent the change in energy for a chemical reaction. They are calculated by subtracting the energy of products from the energy of reactants. Which number would result from an endothermic reaction?
Answer:
800
Explanation:
took the test and got it right
The numbers represent the change in energy for a chemical reaction. They are calculated by subtracting the energy of products from the energy of reactants. 800 would result from an endothermic reaction.Therefore, the correct option is D.
What are the various types of reactions?
There are different types of reactions, such as the endothermic reaction, where the energy is used for the product's formation, and the exothermic reaction.
The energy is released in an exothermic reaction, resulting in a negative result, whereas the energy is used in an endothermic reaction, resulting in a positive result.
Any chemical reaction that absorbs heat from its surroundings is an endothermic reaction. The absorbed energy serves as the activation energy for the reaction to take place.
Thus, 800 would result from an endothermic reaction, the correct option is D.
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Your question is incomplete, most probably your question was
The numbers represent the change in energy for a chemical reaction. They are calculated by subtracting the energy of products from the energy of reactants. Which number would result from an endothermic reaction?
–212
0
-1
800
Please help will give brainliest _________________________________________________________________________________________________________________________________________
Answer:
What subject is this for?
Explanation:
The current disintegration rate for carbon-14 is 14.0 Bq. A sample of wood discovered in an archaeological excavation is found to have a carbon-14 decay rate of 0.875 Bq. If the half-life of carbon-14 is 5,700 y, approximately how old is the wood sample?
Answer:
The wood sample has an age of approximately 22800 years.
Explanation:
The Becquerel ([tex]Bq[/tex]) is a SI unit which describes radioactive activity related to decay of radioactive isotopes, which is equivalent to [tex]\frac{1}{s}[/tex]. The decay of radioactive isotope is described by the following ordinary differential equation:
[tex]\frac{dN}{dt} = -\frac{N}{\tau}[/tex] (Eq. 1)
Where:
[tex]\frac{dN}{dt}[/tex] - Disintegration rate, measured in [tex]\frac{1}{s}[/tex].
[tex]N[/tex] - Amount of remaining radioactive nuclei, dimensionless.
[tex]\tau[/tex] - Time constant, measured in seconds.
By integration the solution of this differential equation is obtained:
[tex]\int {\frac{dN}{N} } = -\frac{t}{\tau}\int dt[/tex]
[tex]\ln N = -\frac{t}{\tau} + C[/tex]
[tex]N(t) = N_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)
Let [tex]N_{1}[/tex] and [tex]N_{2}[/tex] different disintegration rates for Carbon-14 samples, so that:
[tex]N_{1} = N_{o} \cdot e^{-\frac{t_{1}}{\tau} }[/tex] (Eq. 3)
[tex]N_{2} = N_{o}\cdot e^{-\frac{t_{2}}{\tau} }[/tex] (Eq. 4)
If we divide (Eq. 4) by (Eq. 3), then:
[tex]\frac{N_{2}}{N_{1}} = \frac{N_{o}\cdot e^{-\frac{t_{2}}{\tau} }}{N_{o}\cdot e^{-\frac{t_{1}}{\tau} }}[/tex]
[tex]\frac{N_{2}}{N_{1}} = e^{-\frac{1}{\tau}\cdot (t_{2}-t_{1}) }[/tex] (Eq. 5)
If [tex]\Delta t = t_{2}-t_{1}[/tex], we proceed to clear that variable:
[tex]\ln \frac{N_{2}}{N_{1}} = -\frac{1}{\tau}\cdot \Delta t[/tex]
[tex]\Delta t = -\tau\cdot \ln \frac{N_{2}}{N_{1}}[/tex] (Eq. 6)
Time constant is also a function of half-life ([tex]t_{1/2}[/tex]), measured in seconds:
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex]
If [tex]t_{1/2} = 1.798\times 10^{11}\,s[/tex], [tex]N_{1} = 14\,\frac{1}{s}[/tex] and [tex]N_{2} = 0.875\,\frac{1}{s}[/tex], the age of the wood sample is:
[tex]\tau = \frac{1.798\times 10^{11}\,s}{\ln 2}[/tex]
[tex]\tau = 2.594\times 10^{11}\,s[/tex]
[tex]\Delta t = -(2.594\times 10^{11}\,s)\cdot \ln \left(\frac{0.875\,\frac{1}{s} }{14\,\frac{1}{s} } \right)[/tex]
[tex]\Delta t \approx 7.192\times 10^{11}\,s[/tex]
[tex]\Delta t \approx 22805.682\,yr[/tex]
The wood sample has an age of approximately 22800 years.
In Fig 1-2, how should the length indicated by the arrow along the ruler be recorded?
Answer:
C. 0.35cm
Explanation:
The length indicated by the arrow along the ruler should recorded be recorded as "0.35cm".
This is correct because when counting the measurement on the ruler, the first line on the ruler is 0.1cm, the second line is 0.2cm, and so on. The spaces between each line is 0.05cm. So, the arrow is pointing on the space between 0.3cm and 0.4cm.
Therefore, 0.3cm + 0.05cm = 0.35cm.(answer).
The table below gives the numbers of protons, electrons, and neutrons in four atoms.
Number of neutrons
Number of protons
19
Number of electrons
9
Atom
1
12
3
collo
18
10
9
9
9
10
4
19
Based on the table, which atom has a charge of -12
O 1
O 2
03
4
Answer:
THE ANSWER IS D UR WELCOME.
Explanation:
) What would be the effect on the molarity of the NaOH solution if some of the water evaporated from the Florence flask after the NaOH solution was standardized with the KHP
Answer:
The effect is the increasing of the molar concentration.
Explanation:
When you standarize a solution of NaOH with KHP you are establish its molar concentration (That is the amount of moles of NaOH per liter of solution).
If you evaporated some water of the solution, you are increasing its concentration because volume is decreasing doing the amount of moles per liter increasing.
In which of the following atoms are valence electrons in the lowest average potential energy states?
Cl
Br
F
I
Answer:
C) F
Explanation:
Valence electrons are the electrons present in the outermost shell of an atom and have the highest energy level of an atom whereas electrons at ground state or lower orbitals have less potential energy.
This is so because orbitals nearby nucleus are strongly bonded with the atomic nucleus and have less energy than an outermost shell.
So, the potential energy states of an atom depend on the number of orbitals. In the given options fluorine with atomic number 9 has less number of orbitals that is 2 orbitals and valence electrons will be present in second orbitals, so fluorine will have the lowest average potential energy states.
Hence, the correct option is "C) F".
The three dots in the Lewis dot diagram for boron indicates that it. Please help
Answer:
valence electrons
Explanation:
it is outermost shell of electrons
The three dots in the Lewis dot diagram for boron indicates that it has three valence electrons.
The three dots in the Lewis dot diagram for boron indicates that it
can bond with three other atoms. NO. It can bond with less than 3 atoms by forming double or triple bonds.can only form triple covalent bonds. NO. It can also form single and double covalent bonds.has three valence electrons. YES. It has 3 electrons in the outermost electron shell.scores a 3 on Pauling's electronegativity scale. NO. The electronegativity of boron is 2.04.The three dots in the Lewis dot diagram for boron indicates that it has three valence electrons.
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a. Describe the molecule chlorine dioxide, CIO in terms of three possible resonance structures.
b. Do any of these resonance structures satisfy the octet rule for every atom in the molecule? Why or why not?
Answer:
See explanation
Explanation:
The compound ClO2 has 19 valence electrons. ClO2 is a bent molecule with tetrahedral electron pair geometry but has two lone pairs of electrons. This is indicated by the presence of four electron pairs on the outermost shell of the central atom.
The molecule has an odd number of valence electrons, hence, it is generally regarded as a paramagnetic radical. None of the proposed Lewis structures for the molecule is satisfactory because none of them obeys the octet rule.
From the images attached, one can easily see that the electron dots around the oxygen and chlorine atoms does not satisfy the octet rule in all the resonance structures shown.
Calculate the concentration of buffer components present in 210.00 mL of a buffer solution that contains 0.300 M NH4Cl and 0.300 M NH3 immediately after the addition of 1.00 mL of 6.00 M HNO3.
Answer:
[NH3] = 0.270M
[NH4Cl] = 0.327M
Explanation:
The HNO3 will react with the weak base, NH3, as follows:
HNO₃ + NH₃ → NH₄⁺ + NO₃⁻
Initial moles of each specie of the buffer:
NH3 = NH4⁺ 0.210L * (0.300mol/L) = 0.063moles
The moles added of HNO3 = Additional moles of NH4Cl and the moles substracted of NH3:
0.001L * (6mol / L) = 0.006 moles.
After the addition:
Moles NH3 = 0.063mol - 0.006mol = 0.057moles
Moles NH4Cl = 0.063mol + 0.006mol = 0.0069moles
And their concentrations are:
[NH3] = 0.057moles / 0.211L = 0.270M
[NH4Cl] = 0.069moles / 0.211L = 0.327M
Calculate the number of grams of CuSO4 found in 3.29 mL of a 4.00 M CuSO4 solution. ______ grams CuSO4
Answer:
0.0132 g CuSO₄
General Formulas and Concepts:
[tex]\text{Molarity}=\frac{\text{moles of solute}}{\text{liters of solution}}[/tex]
Explanation:
Step 1: Define variables
3.29 mL
4.00 M CuSO₄
x g CuSO₄
Step 2: Define conversions
1000 mL = 1 L
Step 3: Solve
Convert mL to L: [tex]\text{3.29 mL}(\frac{\text{1 L}}{\text{1000 mL}} )[/tex] = 0.00329 LSubstitute: [tex]\text{4.00 M} \ CuSO_4=\frac{\text{x g} \ CuSO_4}{\text{0.00329 L}}[/tex]Multiply both sides by L: [tex]\text{0.01316} \ CuSO_4=\text{x g} \ CuSO_4[/tex]Rewrite: [tex]x = 0.01316 \ g \ CuSO_4[/tex]Step 4: Simplify
We are given 3 sig figs.
0.01316 g CuSO₄ ≈ 0.0132 g CuSO₄
Radium decays to form radon. Which equation correctly describes this decay? Superscript 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 84 Baseline Upper R n + Superscript 4 Subscript 4 Baseline Upper H e Superscript 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 0 Subscript negative 1 Baseline e Superscript 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 0 Subscript + 1 Baseline e Superscript 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e
Answer: 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e
Explanation:
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
The general representation of alpha decay reaction is:
[tex]^{A}_{Z}\textrm{X}\rightarrow ^{A-4}_{Z-2}\textrm {Rn}+ ^{4}_{2}\textrm{He}[/tex]
Representation of Radium decays to form Radon
[tex]^{226}_{88}\textrm{Ra}\rightarrow ^{222}_{86}\textrm {Rn}+ ^{4}_{2}\textrm{He}[/tex]
Thus 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e represents alpha decay.
Answer: D
Explanation:
On edge 2020
How many valence electrons must a lithium atom lose to obtain a complete valence shell?
A. one
B. two
C. three
D. four
Answer:
C. three
Explanation:
Which statements best describe half lives of radioactive isotopes
Answer:
The half-life varies depending on the isotope.
Half-lives range from fractions of a second to billions of years.
The half-life of a particular isotope is constant.
Explanation:
Make sure you add the options
How many milliliters of 0.500 M HBr would be required to react with 40.0 mL of 0.300 M Ca(OH)2?
Answer:
48dm³
Explanation:
Given reaction:
Ca(OH)₂ + 2HBr → CaBr₂ + 2H₂O
Parameters:
Concentration of HBr = 0.5M
Volume of Ca(OH)₂ = 40mL
Concentration of Ca(OH)₂ = 0.3M
Solution:
To solve this problem, we are going to use the mole concept. We solve from the known specie to the unknown.
We first find the number of moles of the known specie which is the Ca(OH)₂ ;
number of moles = concentration x volume
number of moles = 0.3 x 40 x 10⁻³ = 0.012moles
From the reaction equation;
1 mole of Ca(OH)₂ requires 2 moles HBr
0.012 moles of Ca(OH)₂ will require 0.012 x 2 = 0.024moles of HBr
Now,
To find the volume of HBr;
Volume = [tex]\frac{number of moles }{concentration}[/tex]
Volume = [tex]\frac{0.024}{0.5}[/tex] = 0.048dm³
In mL;
Volume 0.048 x 1000 = 48dm³
Observing a phenomenon in the lab includes which of the following?
Throwing away irrelevant items
Sorting through and disposing of police reports
Collecting evidence
Identifying unique features of evidence
Answer:
D
Explanation:
Identifying unique features of evidence
A laboratory is a place where scientific investigations and experiments are conducted. Observing a phenomenon in the lab includes identifying unique features of evidence. Thus, option D is correct.
What is observation?
An observation is said to be the deduction that is seen or heard and is due to the actions of the process or event that are gained from the information from a conducted experiment.
It is an important factor in an experiment and research and is used in the lab to falsify or prove the hypothesis. It is made based on the experimental setup and involves various steps.
The observations are used to draw conclusions and inferences based on the detailed identification of the characteristics of the evidence. The evidence supports the observation.
Therefore, option D. the features of evidence are the correct option.
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My made-up polyatomic ion goldate acts a lot like chlorate (it has the same charge and the same number of oxygens). What would the name be for the acid, HG004(aq)?
a. Hydrogen diogoldate
b. Goldous acid
c. Goldic acid
d. Pergoldic acid
e. None of these
Answer:
d. Pergoldic acid
Explanation:
chlorate = ClO₃⁻
Goldate GoO₃⁻
On this basis we can infer that HClO₄ and HGoO₄ will be similar .
HClO₄ is called perchloric acid , hence HGoO₄ will be called pergoldic acid.
Entropy is a measure of
1.
accuracy
2.
precision
3.
the disorder of a system
4.
the attraction of a nucleus for an electron
Answer:
The answer is actually 3. The disorder of a system.
1. What 2 subatomic particles have charges? List the particle name and its charge.
Answer: Proton - positive charge (+)
Neutron - neutral charge (0)
Electron - negative charge (-)
Explanation:
What is the pH of a solution made by mixing 0.050 mol of NaCN with enough water to make a liter of solution
Answer:
pH = 11
Explanation:
The equilibrium of a weak base as NaCN in water is:
NaCN(aq) + H₂O(l) ⇄ OH⁻(aq) + Na⁺(aq) + HCN(aq)
And kb, the equilibrium constant, is:
Kb = [OH⁻] [HCN] / [NaCN]
Where Kb of NaCN is 2.04x10⁻⁵
In the beginning, the [NaCN] is 0.050mol / L = 0.050M.
Both [OH⁻] and [HCN] are produced from this equilibrium, and its concentration is X, that is:
2.04x10⁻⁵ = [X] [X] / [0.050M]
1.02x10⁻⁶ = X²
X = 1x10⁻³ = [OH⁻]
As pOH = - log [OH⁻]
pOH = 3.00
And pH = 14 - pOH
pH = 11
What specific portion of the gill is used to increase surface area though which gas (oxygen and carbon dioxide) exchange take place?
Answer:
gill lamellae
Explanation:
Gills in fishes are structures that permit fish to carry out gaseous exchange in water. Fishes exchange gases such as oxygen and carbon dioxide using gills.
Fish gills carry out their activity mainly through its major component called the gill lamellae. These are comb-like filaments which help increase the surface area of the gills in order to facilitate gaseous exchange
Lewis based his theory of bonding on? Is this correct
Select the word that is incorrect in the paragraph and replace it with a word which makes the statement correct:
Group 2 elements have two valence electrons in their outer shell and are considered metals. In order to form an ion, a Group 2 element will
gain two electrons and form a cation.
Ions can be made by single element or covalently bonded group of elements. The covalently bonded group of elements is called polyatomic ions or polyatomic atoms. In order to form an ion, a Group 2 element will loose two electrons and form a cation.
What is Ions?Any species that contain charge whether it is positive charge or negative charge is called ions. The example of polyatomic ions are sulfate, phosphate, nitrate etc.
Cation is the species that loose electron and attain positive charge while anion is a species which gain electron and attains negative charge so when anion and cation combine in fixed ration the the overall charge of the molecule is zero that is molecule is neutral, the charge over cation and anion is also called oxidation state. In order to form an ion, a Group 2 element will loose two electrons and form a cation.
Therefore, in order to form an ion, a Group 2 element will
loose two electrons and form a cation.
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In carbon dioxide (CO2), there are two oxygen atoms for each carbon atom. Each oxygen atom forms a double bond with carbon, so the molecule is formed by two double bonds.
Two double bonds means that the total number of electrons being shared in the molecule is
Answer:
The Answer is eight.
Explanation:
Sorry if it's too late and it doesn't help! But I hope you have a magnificent day! :3
Answer:
8
Explanation:
I had this question on my quiz and got it right.
A balloon contains 1.1 L of gas at a pressure of 0.80 atm. How will the volume
change if the pressure is increased to 2.0 atm?
Answer:
Final volume = 0.44 L
Explanation:
Given data:
Initial volume of balloon = 1.1 L
Initial pressure = 0.80 atm
Final volume = ?
Final pressure = 2.0 atm
Solution:
The given problem will be solved through the Boly's law,
"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"
Mathematical expression:
P₁V₁ = P₂V₂
P₁ = Initial pressure
V₁ = initial volume
P₂ = final pressure
V₂ = final volume
Now we will put the values in formula,
P₁V₁ = P₂V₂
0.80 atm × 1.1 L = 2.0 atm × V₂
V₂ = 0.88 atm. L/ 2.0 atm
V₂ = 0.44 L
The Earth can gain or lose matter. True False
Answer:
True
Explanation:
According to some calculations, the Earth is losing 50,000 metric tons of mass every single year, even though an extra 40,000 metric tons of space dust converge onto the Earth's gravity well, it's still losing weight.
Answer:
true
Explanation:
Hydrogen sulfide decomposes according to the following reaction, for which Kc=9.30E-8 at 700 degrees Celsius. 2 H2S(g) --> 2 H2(g) + S2(g) If 0.29 moles of H2S is placed in a 3.0-L container, What is the equilibrium concentration of H2(g) at 700 degrees Celsius?
Answer: The equilibrium concentration of [tex]H_2(g)[/tex] at 700 degrees Celsius is 0.0012 M
Explanation:
Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as [tex]K_c [/tex]
Moles of [tex]H_2S[/tex] = 0.29 mole
Volume of solution = 3.0 L
Initial concentration of [tex]H_2S[/tex] = [tex]\frac{0.29mol}{3.0L}=0.097M[/tex]
The given balanced equilibrium reaction is,
[tex]2H_2S(g)\rightleftharpoons 2H_2(g)+S_2(g)[/tex]
Initial conc. 0.097 M 0M 0M
At eqm. conc. (0.097-2x) M (2x) M (x) M
The expression for [tex]K_c[/tex] is written as:
[tex]K_c=\frac{[H_2]^2\times [S_2]}{[H_2S]^2}[/tex]
[tex]K_c=\frac{(2x)^2\times x}{(0.097-2x)^2}[/tex]
[tex]9.30\times 10^{-8}=\frac{(2x)^2\times x}{(0.097-2x)^2}[/tex]
[tex]x=0.00060[/tex]
Equilibrium concentration of [tex][H_2][/tex]= 2x= [tex]2\times 0.00060=0.0012M[/tex]
which two options are examples of chemical changes?
A. A shinny metal bar glows red and expands when heated.
B. white piece of paper turns black and gives off a smell when burned
C. When two clear colorless liquids are mixed together, a white solid forms
D. A white powder mixed with a clear, colorless liquid makes a solution that is also clear, colorless liquid
Answer:
B
Explanation:
It's the only thing that actually changes into something different and when u burn it it makes chemicals
How would you classify a creepy
crawly with no vertebrae and more
than 6 jointed legs?
Rileach
s. snake
T. spider
v.cockroach
Answer:
T
Explanation:
A Spider is a creepy crawly with no vertebrae and more than 6 jointed legs.
The Spider belongs to the class Arachnida . The Spider can be referred to as a non-vertebrates hence , they don't have a vertebrae(backbone).
The Spider and Cockroach are both non-vertebrates but with different pairs of legs. A cockroach is belongs to the class Insecta in which those under this class have only six jointed legs.
The Spider has eight jointed legs which is more than six and is a characteristic of Arachnids.
A snake on the other hand is a vertebrate which exempts it from being the answer.
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assuming the temperature is held constant, how could you increase the pressure inside a container by a factor of 3
The pressure can be increased by a factor of 3 by decreasing the volume by a factor of 3.
Ideal Gas Equation:Given that the temperature of the system is held constant. So it implies that it is an isothermal process.
Now we know that the ideal gas equation is given by:
PV = nRT
where, P is the pressure
V is the volume
n is the number of moles
R is the gas constant, and
T is the temperature
Assuming n is constant, R is universal as constant, so if T is also constant, then:
PV = constant
So if P becomes 3P. that is the pressure increased by a factor of 3, then V must become V/3, so that: (3P)(V/3) = PV = constant.
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