Explanation:
20984Po→20582Pb+42α
4520Ca→4521Sc+0-1e+00ν
Explanation:
The alpha decay of polonum-209, which consists of the emission of an alpha particle, will leave behind the atom of a different element.
Notice that the identity of the element changes after the decay. This means that you're dealing with a nuclear transmutation, a process that converts an atom of a given element into an atom of a different element.
Determine whether each statement describes an electromagnetic wave, a mechanical wave, or both types of wave.
The question is incomplete, the complete question is;
Which statement describes a difference between electromagnetic and mechanical waves?
A. Mechanical waves cannot be longitudinal, but electromagnetic waves can.
B. Electromagnetic waves cannot move particles, but mechanical waves can.
C. Electromagnetic waves do not require a medium, but mechanical waves do.
D. Mechanical waves do not transfer energy, but electromagnetic waves do.
Answer:
Electromagnetic waves do not require a medium, but mechanical waves do.
Explanation:
A wave is defined as a disturbance along a medium which transfers energy. Waves may be classified as mechanical waves or electromagnetic waves based on their medium of propagation.
A mechanical wave requires a material medium for propagation. An example of a mechanical wave is sound waves. Sound waves are propagated in air.
Electromagnetic waves do not require a material medium for propagation. They can travel through space. An example of electromagnetic waves is light waves.
Which area of science is considered the central science?
O chemistry
O biology
O physics
O environmental science
Answer:
Chemistry
Explanation:
Chemistry helps connect the types of physcial sciences.
Which choice can be classified as a pure substance?
salt water
Iced Tea
pumpkin pie
salt
Answer:
Salt
Explanation:
It is because it has a defined composition.
Answer:
Salt
Explanation:
Pure substances are those that contain atoms or molecules of the same type. For eg: elements are pure (gold, hydrogen etcl.) and compounds (such as water, sodium chloride, etc.), etc.
Rest of choice are impure because they contain a mixture of different things, like pie has eggs, or all sorts of other molecules, salt water has water and salt molecules, and iced tea has water and other molecules associated with tea.
Explain if the combination of iron and copper sulfate is an example of a chemical reaction. Use evidence and scientific reasoning to support your answer.
Describe the redox reaction Check all that apply
2Al(s) + 3ZnCl2(g) - 3Zn(s) + 2AlCl3(aq)
Aluminum atoms transfer electrons to chlorine atoms.
Zinc is reduced
Zinc is the reducing agent
The oxidation number of chlorine does not change,
Aluminum is oxidized
Answer:
Zinc is reduced, The oxidation number of chlorine does not change, and Aluminum is oxidized.
Explanation:
A car reaches 80 km/hr, then suddenly crashed into a concrete wall. Without a seat
belt, the crash test dummy slams into the car's dashboard because
A the crash test dummy's kinetic energy drops to zero
B the dashboard is pushed backwards into the crash test dummy
C the crash test dummy continues its motion until acted upon by an unbalanced
force
D Gravity is pulling the crash test dummy in the direction the car is moving
Answer:
C
Explanation:
inertia
inertia is the reluctance of an object at rest or moving to change its state of rest or motion
because the car was moving, the dummy moves with the speed of the car..so when the crash happened the dummy continued to move..it was feeling reluctant to come to rest so was moving
Which of these reactions shows simple chemical decomposition?
I2 + 2NaCl → 2Nal + Cl2
NaF + HCl → HF + NaCl
H2 + I2 → 2HI
2NaCl → 2Na + Cl2
Answer:
last option is the correct answer
Explanation:
you can see that the chemical NaCl is decomposed or broken into its components Na and Cl.
all other equations have formation of a new compound by reaction of 2 elements or compound
Explain the steps needed to obtain an ammonium salt
Answer:
When an amine is added to a solution of a strong acid, such as hydrochloric acid, the amine nitrogen atom is protonated to produce an ammonium salt. Ammonium salts of low molecular weight are soluble in water if the hydrocarbon portion of the amine is small.Ammonium cation is found in a variety of salts such as ammonium carbonate, ammonium chloride and ammonium nitrate. Most simple ammonium salts are very soluble in water. An exception is ammonium hexachloroplatinate, the formation of which was once used as a test for ammonium.
Chemistry. please help
Answer:
acid +base gives salt and water
acid and carbon gives salt and water and carbon dioxide
acid and metal gives salt and hydrogen
metamorphic rocks result from the
A) cooling and solidification of molten magma
B) compression and cementation of soil particles
C) recrystallization of rocks
D) erosion of rocks
Which of the following accurately describes a Brønsted-Lowry acid?
A)
A Brønsted-Lowry acid receives a protein and has a matching conjugate acid.
B)
A Brønsted-Lowry acid donates a proton and has a matching conjugate base.
C)
A Brønsted-Lowry acid receives a proton and has a matching conjugate base.
D)
A Brønsted-Lowry acid donates a protein and has a matching conjugate acid.
Answer:
B. A Brønsted-Lowry acid donates a proton and has a matching conjugate base.
Explanation:
Here's HA is bronsted acid and its conjugate base pair is A-.
Answer:
Explanation:
The actual answer is B. The equation has an acid on one side and a base on the other. The acid donates a proton. Donates means gives up the equivalent of a proton.
Calculate the molality of a solution that contains 51.2 g of naphthalene, C10H8, in 500 mL of carbon tetrachloride. The density of CCl4 is 1.60 g/mL.
Answer: The molality of naphthalene solution is 0.499 m
Explanation:
Density is defined as the ratio of mass and volume of a substance.
[tex]\text{Density}=\frac{\text{Mass}}{\text{Volume}} [/tex] ......(1)
Given values:
Volume of carbon tetrachloride = 500 mL
Density of carbon tetrachloride = 1.60 g/mL
Putting values in equation 1, we get:
[tex]\text{Mass of carbon tetrachloride}=(1.60g/mL\times 500mL)=800g[/tex]
Molality is defined as the amount of solute expressed in the number of moles present per kilogram of solvent. The units of molarity are mol/kg. The formula used to calculate molarity:
[tex]\text{Molality of solution}=\frac{\text{Given mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Mass of solvent (in g)}}[/tex] .....(2)
Given values:
Given mass of naphthalene = 51.2 g
Molar mass of naphthalene = 128.17 g/mol
Mass of solvent = 800 g
Putting values in equation 2, we get:
[tex]\text{Molality of naphthalene}=\frac{51.2\times 1000}{128.17\times 800}\\\\\text{Molality of naphthalene}=0.499m[/tex]
Hence, the molality of naphthalene solution is 0.499 m
PLEASE HELP!
mass number - atomic number =
Answer:
Number of neutrons
Explanation:
The mass number represents the number of protons and neutrons combined and the atomic number only represents the number of protons.
mass number - atomic number = number of neutrons
Answer:
mass number - atomic number = number of neutrons
Explanation:
The mass number of an atom is equal to the number of protons plus the number of neutrons that it contains. The mass number minus the atomic number represent the number of neutrons.
Which of the following would have the best thermal insulation properties?
A. A cotton sweater
B. A rubber rain_at
C. A down-filled coat
D. A nylon windbreaker
Answer:
C. A down-filled coat via a p e x
Thermal insulation maintains the temperature inside the system and inhibits heat transfer. A down-filled coat would have the best thermal insulation properties. Thus, option C is correct.
What is thermal insulation?Thermal insulation is the property of the substance to resist the heat and energy transfer from a substance of abundance to a lesser concentration. They lack the conducting particles.
It inhibits the heat to get transferred to other substances. The minimum heat transfer is achieved by the structural formation and the choice of the substance.
A down-filled coat is made of insulation material that keeps warm during the winters as its structure can trap and retain heat making the person warm during colds.
Therefore, option C. A down-filled coat best shows thermal insulation.
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1 When the equation
Hg + Agt → __Ag + Hg2+
is correctly balanced using smallest whole numbers, the
coefficient in front of the Ag+ will be
A 5
B 2.
C 3
D 4.
Answer: I think 5
Explanation:
Balanced equations use the whole numbers to conserve the atomic numbers. When the reaction is balanced then 2 will be the coefficient in front of the Ag⁺.
What is a balanced reaction?A balanced reaction has symbols and whole numbers that represent the number of atoms and molecules of the reactants and the products in a reaction mixture.
The reaction between mercury and silver is shown as:
Hg + 2Ag⁺ → 2Ag + Hg²⁺
This can be checked by the redox half-reactions as:
2Ag⁺ + 2e⁻ → 2Ag⁰
Hg⁰ → Hg²⁺ + 2e⁻
Therefore, the silver cation gained two-electron and became a silver atom.
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how does a scientist answer a scientific question
Answer:
Observes and measure
Explanation:
Answer:
they use tests
Explanation:
they search for evidence using experiments,an experiment is a test to see if their explanation is right or wrong. evidence is made up of observations a scientist makes during an experiment
Calculate the volume in Liters of 15 moles of Neon gas (at STP)
At the carnival, a baby was given a helium balloon whose
pressure equaled the atmospheric pressure at the carnival
which was 102.7 kPa. However, the baby wasn't paying
attention and the balloon floated away into the troposphere
where the atmospheric pressure is 97.8 kPa. What is the
positive difference between the pressure in the balloon and
the pressure of the troposphere in atm?
atm
Answer: 0.048 kPa
Explanation: no clue i just looked it up you’re welcome y’all:)
Which of the following is NOT a sign of a chemical change? (HINT: only 2 answers, the rest are chemical change)
1. tarnished is formed
2. gas is produced
3. weight change
4. Temperature change
5. color change
6. nothing changes
7. forms a precipitate
8. energy is released
Need this done today please!!
Answer:
3 and 6 (weight change and nothing changes)
Explanation:
Hi there!
A chemical change is a change when matter changes into a new substance and has a new chemical property.
The signs that a chemical change is taking place are:
1. change in color
2. change in smell
3. change in energy (for example, there is a change in temperature (thermal energy))
4. a gas is formed (fizzing/bubbling/foaming are signs of this!)
5. formation of a solid (a precipitate)
A physical change is any change to the size, shape, or state of a substance. The substance still has the same chemical property.
these are your eight options:
1. tarnished is formed (a sign of a chemical change; a change in color)
2. gas is produced (a sign of a chemical change)
3. weight change (NOT a sign of a chemical change. Even though the weight changed, the substance still has the same chemical composition and therefore, there wasn't any change to its chemical identity)
4. Temperature change (a sign of a chemical change; a change in energy)
5. color change (a sign of a chemical change)
6. nothing changes (NOT a sign of a chemical change. If nothing happens, the substance is still the same as it was originally and there was no change to its chemical identity.)
7. forms a precipitate (a sign of a chemical change)
8. energy is released (a sign of a chemical change)
therefore the two options that are NOT a sign of a chemical change are 3 and 6 (weight change and nothing changes)
Hope this helps! :)
Someone help me am i right or wrong
Answer:
You right!
Explanation:
Answer: Yes your right
Is the reaction shown, relating carbon dioxide and pH, a reversible process?
Answer:
Yes it is reversible for the reaction.
Chem pls help me thanks very much
Answer:
Flourine reacts with Sodium bromide to give Silver flourine and Bromine
Hope u understand
Thank You
Please mark as brainliest
Answer:
posaaaaaaaaaaaaaaaaaaaaa
When choosing a respirator for your job, you must conduct a _____ test.
A) Weight
B) Breathing
C) Fit
D) Practice
(b) Given that ΔG° for reaction 1 is positive (155kJ/molrxn), what must be true about the sign of ΔH° for the reaction? Justify your answer
Answer: The sign of ΔH° for the reaction is positive.
Explanation:
Given: [tex]\Delta G^{o}[/tex] = 155 kJ/mol (1 kJ = 1000 J) = 155000 J/mol
The relation between [tex]\Delta G^{o}[/tex] and [tex]\Delta H^{o}[/tex] is as follows.
[tex]\Delta G^{o} = \Delta H^{o} - T \Delta S[/tex]
As the given value of [tex]\Delta G^{o}[/tex] is positive. This means that on further calculation the value of [tex]\Delta H^{o}[/tex] will come out to be positive.
Thus, we can conclude that the sign of ΔH° for the reaction is positive.
In a closed system, the amount of the non-expansion work that can be done is called gibs free energy. The enthalpy cahnge will be positive.
What is enthalpy?The enthalpy of the system is given as the addition of products of the pressure and the volume with the internal energy of the system.
The Gibbs free energy is given by the formula:
[tex]\rm \Delta G^{\circ} = \Delta H ^{\circ} - T\Delta S[/tex]
When Gibbs's free energy is positive then the enthalpy will become positive.
Therefore, the enthalpy change will be positive.
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Please help me school ends tomorrow
Which scenario describes a transfer of mechanical energy to heat and sound energy?
Question 7 options:
A)
a plant using energy from the sun to create food
B)
a very high pitched sound causing a glass to break
C)
talking into a microphone.
D)
clapping hands
Answer:
D) clapping handsExplanation:
hope it's helpful
What method could be used to separate the
components of gasoline?
Answer:
Distillation
Explanation:
Reason being the process is only used to separate liquids with boiling points greater than 25 °C
Answer:
b
Explanation:
correct on edge
What is the pressure exerted by 68.0 g of nitrogen trihydride gas in a 50.0L container at 30.0 C?
Answer:
Molecular mass of NH3 = ( 14 + 3 ) = 17 g
[tex]PV = \frac{m}{m _{r}} RT \\ P \times 50.0 \times {10}^{ - 6} = \frac{68.0}{17} \times 8.314 \times (30.0 + 273) \\ P = \frac{68.0 \times 8.314 \times 303}{17 \times 50.0 \times {10}^{ - 6} } \\ P = 2.02 \times {10}^{8} \: Pascals[/tex]
All molecules have London forces between them, but dipole-dipole and hydrogen bonding are so much stronger that when they are present we
can ignore London forces. Only NONPOLAR molecules will SHOW LDF. Which of these has ONLY LDFs?
A. I2
B. HF
C. NH3
D.H2S
Answer:
a
Explanation:
khan academy
Among the options given, only [tex]I_2[/tex] shows London-Dispersion forces. Thus, the correct option for this question is A.
What is the London-Dispersion force?The London-Dispersion force may be defined as a type of provisional attractive force that arises when the electrons in two adjacent atoms tenanted positions that construct the atoms to form temporary dipoles. It is considered the weakest intermolecular force.
[tex]H_2S[/tex] shows dipole-dipole interactions because hydrogen and sulfur have huge electronegative differences. Due to this, their bonds are polar. [tex]NH_3[/tex] shows hydrogen bonding between them. HF shows dipole-dipole interactions because it is a polar covalent molecule.
Therefore, only [tex]I_2[/tex] shows London-Dispersion forces. Thus, the correct option for this question is A.
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a bucket of water cooling at 300k produces a change in enthalpy of -300kJ. what is /\ (delta) Ssurr
a. -1 j/k
b. 1 j/k
c. 1000 j/k
d -1000 j/k
The change in the entropy of the surrounding, ΔSₛᵤᵣ during the cooling process is 1000 J/K (Option C)
What is entropy?Entropy is simply defined as the measure of the degree of the disorderliness of a system. Mathematically, it can be expressed as:
ΔS = ΔH / T
Where
ΔS is the change in entropy of system
ΔH is the enthalpy change
T is the temperature
How to determine the entropy of the system (ΔSₛᵧₛ)Enthalpy change (ΔH) = –300 KJ Temperature (T) = 300 K Change in entropy of system (ΔSₛᵧₛ) =?ΔS = ΔH / T
ΔSₛᵧₛ = –300 / 300
ΔSₛᵧₛ = –1
ΔSₛᵧₛ = –1 × 1000
ΔSₛᵧₛ = –1000 J/K
How to determine the entropy of the surrounding Change in entropy of system (ΔSₛᵧₛ) = –1000 J/KChange in entropy of surrounding (ΔSₛᵤᵣ) =?ΔSsys = –ΔSsur
–1000 = –ΔSsur
ΔSₛᵤᵣ = 1000 J/K
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Vincent dissolves 6.5 g of bromic acid, HBrO3, to prepare 600.0 mL of solution. Calculate the concentration of the acid Vincent produced.
Answer: The concentration of the acid Vincent produced is 0.083 M.
Explanation:
Given: Mass = 6.5 g
Volume = 600.0 mL (1 mL = 0.001 L) = 0.6 L
Moles is the mass of substance divided by its molar mass. So, moles of bromic acid (molar mass = 128.91 g/mol) are calculated as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{6.5 g}{128.91 g/mol}\\= 0.05 mol[/tex]
Molarity is the number of moles of a substance present in liter of a solution.
Therefore, molarity (concentration) of the given solution is calculated as follows.
[tex]Molarity = \frac{no. of moles}{Volume (in L)}\\= \frac{0.05 mol}{0.6 L}\\= 0.083 M[/tex]
Thus, we can conclude that the concentration of the acid Vincent produced is 0.083 M.
