Answer:
The answer is C
Explanation:
Duh its the name HALF LIFE!!
just a way to remember
The statement which is true about the half-life of a source is (D) It is half the time it takes the activity of the source to decrease to zero. Hence the correct option is (D)
What is Half Life Period of a source ?Half-life is the length of time it takes for a radioactive element to decay to half of its initial value.
This suggests that a source's activity has a half-life when it takes time for it to decrease to half its initial value.
It is the amount of time needed for half of the atomic nuclei in a radioactive sample to spontaneously decay, which releases energy and particles into other nuclear species. Alternatively, it is the amount of time needed for the radioactive sample to disintegrate at a rate of one per second.
Therefore, The statement which is true about the half-life of a source is (D) It is half the time it takes the activity of the source to decrease to zero. Hence the correct option is (D)
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Fe2O3 + 6HCl → 2FeCl3 + 6H20 How many atoms of FeCl3 will be produced if 9.3 x 1023 atoms of HCl are used for this reaction? 6.7 x 1023 atoms FeCl3 3.1 x 1023 atoms FeCl3 9.3 x 1023 atoms FeCl3 1.2 x 1023 atoms FeCl3
Answer:
3.1x10²³
Explanation:
I'm going to answer the question assuming the number of molecules of FeCl₃ is asked, rather than the number of atoms.
Fe₂O₃ + 6HCl → 2FeCl₃ + 6H₂OFirst we convert 9.3x10²³ atoms of HCl into moles of HCl, using Avogadro's number:
9.3x10²³ atoms ÷ 6.023x10²³ atoms/mol = 1.54 mol HClThen we convert 1.54 moles of HCl into moles of FeCl₃, using the stoichiometric coefficients of the reaction:
1.54 mol HCl * [tex]\frac{2molFeCl_3}{6molHCl}[/tex] = 0.51 mol FeCl₃Finally we calculate how many FeCl₃ molecules are there in 0.51 moles:
0.51 mol * 6.023x10²³ molecules/mol = 3.4x10²³ moleculesThe closest option is 3.1x10²³.
The number of atoms produced is four times the number of FeCl₃ molecules produced.
Alleles are different forms of which genetic structure?
A. DNA
B. Cells.
C. Genes
D. Chromosomes
Answer:
answer is c
Allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.
Four hundred and fifty two
bullfrogs live in a marsh that
is sixty eight square
kilometers. What is the
population density of the
bullfrogs
per square
kilometer?
WILL GIVE BRAINLIST
Answer: 6.65 bullfrogs per square
kilometer
Explanation:
The formula to calculate the population density will be:
= N/A
where,
N = total population = 452
A = land area = 68km²
Therefore, population density will be:
= N/A
= 452/68
= 6.65 bullfrogs per square
kilometer
Plz help me : Copper (I) chloride CuCl is made up of:
A. all metals
B.all nonmetais
C. Metal and nonmetal
____________Polar regions get less of the sun's direct rays, they are the coldest climates on Earth. A because , B although, C Howerer, D Consequently / what best word fits in the blank space what makes sense.
Answer:
Because Polar regions get less of the sun's direct rays, they are the coldest climates on Earth.
Explanation:
The bond that holds together positive and negative ions is
called a(n) bond.
Answer:
Ionic bond
Explanation:
An ionic bond holds positive and negative ions together.
What contains a single element 1. Acid/Base 2. Redox 3. Precipitation
Answer:
hydrogen ion dissolve in water is acid and hydroxide ion dissolve in water is basi
the recation in which oxidation and reduction goes side by side is redox redaction
why is oxygen more electronegative than nitrogen
Answer:
Oxygen has 8 protons in the nucleus while nitrogen only has 7. A bonding pair will experience more attraction from the oxygen's nucleus than from nitrogen's, and so the electronegativity of oxygen is greater.
Why don’t different varieties of corn plants grow to the same size under similar growing conditions?
Help me please please i is in middle school need help ple
the answer is that it is a
If you started with 23g of Mg and 412 ml of 2.6M HCl, find the limiting reactant. If you collected the hydrogen gas over water at a temperature of 81OC, what is the volume of just the water if the total pressure is 2.23 atm? How many grams of water vapor are in the container?
Answer:
See explanation.
Explanation:
Hello there!
In this case, according to the description of the chemical reaction, it is possible to write the corresponding equation as follows:
[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]
Whereas we are given the mass of magnesium and the concentration and volume of HCl; it means that we can calculate the moles of hydrogen yielded by each of these reactants in order to identify the limiting reactant:
[tex]m_{H_2}^{by\ Mg}=23gMg*\frac{1molMg}{24.305gMg}*\frac{1molH_2}{1molMg}=0.95gH_2 \\\\m_{H_2}^{by\ HCl}=0.412L*2.6\frac{molHCl}{1L}*\frac{1molH_2}{2molHCl}*=0.54gH_2[/tex]
Therefore, we infer that the limiting reactant is HCl as it yields the fewest moles of hydrogen. Next since the vapor pressure of water at 81 °C is about 0.4675 atm we infer that the pressure of hydrogen is 2.23 atm - 0.4675 atm = 1.7625 atm. In such a way, we use the ideal gas equation to obtain the volume of hydrogen:
[tex]V_{H_2}=\frac{0.54molH_2*0.08206\frac{atm*L}{mol*K}*(81+273.15)K}{1.7625atm} \\\\V_{H_2}=8.9L[/tex]
Finally, since the pressure of water is 0.4675 atm and the volume is the same for both, we obtain the moles of water and subsequently the required grams as shown below:
[tex]n_w=\frac{0.4675atm*8.9L}{0.08206\frac{atm*L}{mol*K}*(81+273.15)K} \\\\n_w=0.143molH_2O\\\\m_w=0.143molH_2O*\frac{18.02gH_2O}{1molH_2O} =2.6gH_2O[/tex]
Best regards!
a point of reference is anything that seems steady that is used compare the position of an object
TRUE OR FALSE?
Answer:
True
Explanation:
hope it'll help!!
That statement would be true
Global climate change is
a.
a politically motivated deception generated by scientists with an environmentalist agenda.
b.
hotly debated by a deeply divided scientific community.
c.
a hypothesis that is not yet well supported by scientific evidence.
d.
understood by science to be a fact, and as largely the result of human activities.
how many grams of hexane(C6H14) would be need to make 562 of carbon dioxide
The mass of hexane, C₆H₁₄ that would be needed to produce 562 grams of carbon dioxide, CO2 is 183 g
How do I determine the mass of hexane, C₆H₁₄ needed?We'll begin by writing the balanced equation for the reaction.
2C₆H₁₄ + 19O₂ → 12CO₂ + 14H₂O
The following are obtained from the equation:Molar mass of C₆H₁₄ = 86 g/molMass of C₆H₁₄ from the balanced equation = 2 × 86 = 172 g Molar mass of CO₂ = 44 g/molMass of CO₂ from the balanced equation = 12 × 44 = 528 gFrom the balanced equation above,
528 g CO₂ were produced from 172 g of C₆H₁₄
With the above information, we shall determine the mass of hexane, C₆H₁₄ needed to produce 562 g CO₂. Details below:
From the balanced equation above,
528 g CO₂ were produced from 172 g of C₆H₁₄
Therefore,
562 g of CO₂ will react to produce = (562 × 172) / 528 = 183 g of C₆H₁₄
Thus, the mass of hexane, C₆H₁₄ needed is 183 g
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When was the "Permian Era"?
Answer:
298.9 million years ago - 251.902 million years ago
Explanation:
It might be in the 2011 Earth Science Review Packet so maybe go check that out
How many grams would 8.88 x 1029 atoms of NaCl be equivalent to?
Answer:
8.65x10 7 grams of nacl
Explanation:
There are 6.02x10 23 atoms per one mol
so
8.88x 10 29 x (1/6.02 x 10 23)
Will give us mols of NaCl
to go from mols to grams we multiple mols by molar mass
so
1.48x10 6 mols of Nacl x 58.44 g/mol = 8.65x10 7 grams of nacl which can be converted to
86500 kg
"Calculate the pH of a 0.15 M HBr solution AND classify the solution of acidic, neutral, and basic"
a. 0.82 basic
b. 0.82 acidic
c. 13.9 basic
d.13.9 acidic
Answer:
la respuesta es la letra: b
Reactants are an acid and a base, which one describes this? 1. Acid base 2. Redox 3. Precipitation 4. Combustion
Answer:
The answer is 1. acid-base
Explanation:
This is pretty self-explanatory, when an acid and base react, it is called an acid-base reaction. Redox reactions are where two reactants exchange electrons, precipitation reaction is where a solid is formed, and combustion reaction is where a compound is reacted with oxygen so none of those can be the answer.
order these elements by decreasing electron affinity:
Na, Al, S, K, F
Answer:
increasing to decreasing:
F--- S--- Al--- Na--- K
not sure...
Suppose the galvanic cell sketched below is powered by the following reaction: (s)(aq)(aq)(s) Write a balanced equation for the half-reaction that happens at the cathode of this cell. Write a balanced equation for the half-reaction that happens at the anode of this cell. Of what substance is E1 made? Of what substance is E2 made? What are the chemical species in solution S1? What are the chemical species in solution S2?
Answer:
Hello the required Image related to your question is missing attached below is the missing Image
answer :
a) Ni²⁺(aq) + 2e⁻ ⇒ Ni(s)
b) Fe(s) ⇒ Fe²⁺(aq) + 2e⁻
c) Fe (s)
d) Ni ( s )
e) Fe²⁺(aq) and SO⁻²₄ (aq)
f) Ni²⁺(aq) and SO⁻²₄(aq)
Explanation:
a) Balanced equation for the half-reaction at the cathode of the cell
Ni²⁺(aq) + 2e⁻ ⇒ Ni(s)
b) Balanced equation for half reaction at the anode of the cell
Fe(s) ⇒ Fe²⁺(aq) + 2e⁻
c) E1 is made of Fe (s)
d) E2 is made of Ni ( s )
e) chemical species in solution S1 = Fe²⁺(aq) and SO⁻²₄ (aq)
f) Chemical species in solution S2 = Ni²⁺(aq) and SO⁻²₄(aq)
The name of an alcohol side chain is known as an alkoxy group. True or false?
Explain, in terms of subatomic particles in energy states, how the colors in a fireworks display are produced
Salts are heated to extremely high temperatures during a display of fireworks. The salts' ions pick up energy and get excited. Exciting hues are created as energy in the form of light is emitted from the ions. Each salt's metal ion can be identified by the hue of the light that is emitted.
What are subatomic particles?Subatomic particles refer to the three fundamental particles that make up the atom.
The subatomic particles include:
electronsprotons, and neutronsElectrons occupy several energy states. When electrons gain energy, they move to a higher energy state. The electrons on returning to a lower energy state emit radiation that is seen as several light color displays in fireworks.
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What is the molecular formula of a compound with a molecular mass of 63.0g and an empirical formula of CH3O
Answer:
I think first molar mass of ch3o which is 31
Explanation:
Which type of molecule is shown below?
O A. Alkyne
O B. Alkane
C. Alkene
O D. Aromatic
The type of molecule shown in the image has been an alkyne. Thus option A is correct.
The molecules formed by hydrogen and carbon are hydrocarbons, These are the organic compounds with the sharing of electrons in between the atoms.
The number of electrons shared results in the bond formed. The compound with only a single bond has been alkane. The presence of sharing of 2 atoms results in a double bond, and the compounds are alkene. The triple bond compounds are alkynes.
The given structure has the presence of a triple bond in the structure, thus the image has been of an alkyne. Thus, option A is correct.
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Does sublimation change chemical or physical change
Answer:
Yes, sublimation is a physical change because it involves a change of state from solid to gas of a substance when it is heated.
26. The water of the surface of the ocean is termed surface currents and moves in a regular pattern. They don't depend on the weather and move heat around Earth. What two things create surface currents?
The indicator methyl red has different molecular structures at high and low pH.
a. True
b. False
Answer:
a. True
Explanation:
Methyl red is an indicator widely used in quality control of oxides as Zinc oxide in the titration with sulfuric acid.
As is used in titrations of acid-base reactions the indicator change in colour. Is red when the pH < 4.4 (Acidic Solutions) and is yellow when pH > 6.2 (Neutral-Basic solutions).
A change in colour means the structure of the indicator is changing with pH. Thus, the answer is:
a. Truewhich statements describe what happen in a redox reaction?
a. one atom gains electrons and one loses electrons
b. the cations on two substances trade places
c. electrons move from one substance to another
d. there are two oxidation reactions
Answer:
A or C
Explanation:
I don't know if I'm correct but I think it's A or C you don't have to choose them.
If sugar was broken back down into CO2 and H2O what kind of change would that be?
A. Chemical change
B. Radical change
or
C. Physical change
Answer: chemical change
Let's repeat this process for the atoms that make up the substances that do not conduct when dissolved in water. What do you notice now?
Answer:
Explanation:
If they do not disolve in water they are non electrolyte and hence will not conduct eletricity. If you had a lab where a batter was supplying power and the wire carryin the electricity went through a water bath if the water was pure and nothing disolved in it the light would not turn on but if you added something like salt it would conduct the electricity