Answer:
false it's 24 hours long.
Iodine-131 has a half life of 8.040 days how long will it take for a 40.0 grams sample of iodine 131 to decay to 0.75g
Answer:
[tex]t=46.13days[/tex]
Explanation:
Hello there!
In this case, since the radioactive decay is considered as first-order kinetic model, whereby the remaining mass of the radioactive material involves the initial one, the rate constant and elapsed time:
[tex]A=Ao*exp(-kt)[/tex]
As we were not initially given the rate constant, we can use the half-life to calculate it as follows:
[tex]k=\frac{ln(2)}{8.040days}=0.08621days^{-1}[/tex]
Thus, we can calculated the elapsed time for the given conditions to obtain:
[tex]t=\frac{ln(0.75g/40.0g)}{-0.08621days^{-1} }\\\\t=46.13days[/tex]
Regards!
For Fe, its atomic number is 26 and its mass number is 56. How many neutrons does it have?
Answer:
the number of neutrons available is 30
Explanation:
Given that
The atomic number is 26
And, the mass number is 56
We need to determine the number of neutrons does it have
So, the number of neutrons is
= Mass number - atomic number
= 56 - 26
= 30
Hence, the number of neutrons available is 30
The same would be considered and relevant
M
Mass can be measured in local units like dharni pau eto. Discuss the advantages of using
standard units of mass over the local units of mass. (Any two points)
N2 Points)
soup answer
Answer:
1.They are reliable.
2.They dont vary from person to person
A sample of chlorine gas occupies a volume of 0.025L at 300 K. At 600K, what will the volume be?
A)808 L
B)50 L
C)0.050 L
D)0.088 L
Answer: The volume at 600 K will be 0.050 L.
Explanation:
Given: [tex]V_{1}[/tex] = 0.025 L, [tex]T_{1}[/tex] = 300 K
[tex]V_{2}[/tex] = ?, [tex]T_{2}[/tex] = 600 K
Formula used is as follows.
[tex]\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}\\\frac{0.025 L}{300 K} = \frac{V_{2}}{600 K}\\V_{2} = 0.050 L[/tex]
Thus, we can conclude that the volume at 600 K will be 0.050 L.
Iodine is prepared both in the laboratory and commercially by adding Cl2(g) to an aqueous solution containing sodium iodide. 2NaI(aq)+Cl2(g)⟶I2(s)+2NaCl(aq) How many grams of sodium iodide, NaI, must be used to produce 87.9 g of iodine, I2?
Answer:
[tex]m_{NaI}=104gNaI[/tex]
Explanation:
Hello there!
In this case, given the balanced chemical reaction, it is possible to evidence that the mole ratio of sodium iodide to iodine is 2:1 and the molar masses are 149.89 and 253.81 g/mol respectively; in such a way, we write the following stoichiometric setup in order to obtain the required grams of sodium iodide:
[tex]m_{NaI}=87.9gI_2*\frac{1molI_2}{253.81gI_2}*\frac{2molNaI}{1molI_2}*\frac{149.89gNaI}{1molNaI} \\\\m_{NaI}=104gNaI[/tex]
Regards!
Which of the following is most helpful for identifying an organism using a dichotomous key?
Its average lifespan
Its sources of food
Its habitat
Its physical structures
Answer:
Its physical structure
Explanation:
NEED ASAP!
Describe how scientific discoveries have changed our culture, national and international legislation.
Answer:
discoveries that can change little aspects of our daily lives or finding cures for diseases that have hounded humanity, scientists have been hard at work trying to push us toward a brighter future.
Explanation:
thats what i got from my research :D
Given that ammonia (NH3) acts as a weak base in water with a Kb of 1.8 x 10-5 at 298.0 K, calculate the pH at 298.0 K of a solution prepared by mixing 100.0 mL of a 0.050 M aqueous solution of ammonia with 20.0 mL of a 1.00 M aqueous solution of nitric acid. The final volume of the solution is 120.0 mL.
Answer:
pH = 0.903.
Explanation:
Hello there!
In this case, according to the given information about the problem, we can notice there is a reaction between nitric acid and ammonia, whereas just the H ions from the former are relevant:
[tex]NH_3(aq)+H^+(aq)\rightleftharpoons NH_4^+(aq)[/tex]
Thus, we first calculate the consumed moles of ammonia, it order to evaluate the moles after the reaction:
[tex]n_{H^+}=0.020L*1.00mol/L=0.020mol\\\\n_{NH_3}=0.100L*0.050mol=0.005mol[/tex]
It means there is a leftover of moles of hydrogen ions of 0.015mol; then, we calculate the molarity of the resulting solution as follows:
[tex][H^+]=\frac{0.015mol}{0.120L}=0.125M[/tex]
Finally, we use the formula for the calculation of the pH to obtain:
[tex]pH=-log(0.125)\\\\pH=0.903[/tex]
Which means this solution is highly acidic.
Regards!
Scientist introducing a gene to the DNA of these fish that cause the fish to glow an example of which application of biotechnology?
A. Artificial selection
B. Genetic Engineering
C. cloning
D. Artificial intelligence
Answer:
The correct answer is B
Explanation:
Genetic engineering is an example of which application of because the genes are changed to get the desired features in an organism.
What is genetic engineering?Genetic engineering is the process in which we alter the genetic makeup of an organism to produce desired characterictics in that organism.
So we can conclude that Genetic engineering is an example of which application of because the genes are changed to get the desired features in an organism.
Learn more about here Genetic engineering: https://brainly.com/question/2780091
The name for the process that causes fertile land to become dirt-like is??
Deforestation
Urbanization
Construction
Desertification
Answer:
Desertification?
Explanation:
Desertification is when fertile lands become desert like
8.45 cm - 3.55 cm = ?
Answer:
4.9cm or 4.90cm
Explanation:
Use column method and align the numbers. Make sure you add the decimal point before you write the answer, otherwise the value would be wrong.
Answer:
4.90
Explanation:
8.45.
-3.55
minus those two and you'll get the sum!
which element have the formula C6H12O6?
Answer: Glucose is a simple sugar with six carbon atoms and one aldehyde group.
Explanation: hope this helps you
Answer:
the answer of this is glucose
what is Hydroelectricity?
Answer:
Hydroelectricity, or hydroelectric power, is electricity produced from hydropower. In 2015, hydropower generated 16.6% of the world's total electricity and 70% of all renewable electricity, and was expected to increase by about 3.1% each year for the next 25 years.
Explanation:
Answer:
The electricity which is produced from flowing water or from the force exerted by the flowing water is called Hydroelectricity..
hope it is helpful to you
how do some plants grow and survive in the harshest environments like the dessert or under water
Answer:
Adaptation
Explanation:
Some plants grow and survive in the harshest environments like the desert or underwater by adapting to the environment. For example, some plants in the desert have thick, waxy skin to reduce loss of water and to reflect heat. They also have large, fleshy stems to store water. Also, specific plants like cacti in the desert have spikes to protect them from animals wishing to use stored water. These adaptations help them to grow and survive in the desert.
In the ocean, plants have adapted to absorb all the water and carbon dioxide they need from the water they live in. Just as cacti have adapted to live in brutally hot deserts, ocean plants have adapted to deal with things like ocean tides and the salinity (or salt levels) of the water around them. Many ocean plants cling tightly to rocks in order to avoid being swept away by ocean tides.
Hope this helps! Can I have brainliest?
Describe the process used to dilute a stock solution?
Answer:
Heyaa!! I'm *✧･ﾟ:*Pinky!! *:･✧ And i'm here to inform you that you're answer is...
Explanation:
✧･ﾟ: *✧･ﾟ:**:･ﾟ✧*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:･ﾟ✧*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:✧*:✧✧･ﾟ:*✧･ﾟ:*✧･ﾟ:
*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:･ﾟ✧*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:･ﾟ✧*:･ﾟ*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:✧*:✧*:･ﾟ･ﾟ
*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:･ﾟ✧*:･ﾟ✧ !!!!! Answer: add more solvent to decrease the concentration. A stock solution is a concentrated form of a particular chemical. To make a solution from the stock solution, a required amount of the stock solution has to be taken out and this will be diluted with pre-calculated amount of the correct solvent !!!! *:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:･ﾟ✧*:･ﾟ✧
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*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:･ﾟ✧*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:･ﾟ✧*:･ﾟ*:･ﾟ✧✧･ﾟ: *✧･ﾟ:**:✧*:✧*:･ﾟ･ﾟ
Have An Amazingly Good Day!!
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Please, can anyone confirm that my answers are correct?
Will give brainiest to first correct answer! (No links pls)
PLZ HELP
I don't understand with the question number 4, does anybody understand how to do it?
Answer:
iodine = I
sodium= Na
oxygen= O2
aluminum = AI
nitrogen=N
sulfur= S
bromine =Br
magnesium =Mg
Ann is studying acid base neutralization reactions and mixes sodium hydroxide and hydrochloric acid. The reactants were clear,
colorless solution and mixing them produces a clear, colorless final solution and the beaker becomes warm. She knows this reaction
forms liquid water and an aqueous salt based on the neutralization rules as shown by the chemical equation. What physical evidence
indicates that there has been a chemical rea
NaOH(aq) + HCl(aq) - NaClaq) + H2 °C)
图 40)
A)
The solution changes color.
B)
Precipitate formation occurs.
C)
The beaker changes temperature.
D)
Gas bubbles form during the reaction.
Answer:C
Explanation:
Got it right in usatestprep
The physical evidence that indicates that there has been a chemical reaction is that the beaker changes temperature and the correct option is option C.
What is Neutralization reaction?
Neutralization is a chemical reaction in which acid and base react to form salt and water. Hydrogen (H⁺) ions and hydroxide (OH⁻ ions) react with each other to form water.
The strong acid and strong base neutralization have a pH value of 7.
The beaker gets warm which indicates that the reaction between acid and base is an exothermic reaction releasing heat energy into the surroundings.
Therefore, The physical evidence that indicates that there has been a chemical reaction is that the beaker changes temperature and the correct option is option C.
Learn more about Neutralization reaction, here:
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Which rule for assigning oxidation numbers is correct?
a.)Hydrogen is usually -1
b.)Oxygen is usually -2
c.)A pure group 1 element is +1
d.)A monatomic ion is 0
Answer:
Answer... Option B. Oxygen is usually -2; except in Peroxides
A reaction yield 6.26 g of a product what is the percent yield if the theoretical yield is 18.81 g
Explanation:
remember the equation percentage yield = actual/theoretical yield
so 6.26/18.81 X 100 gives u 33.28017012 so to 3 SF ot would be 33.3%
hope this helps:)
The statement, that describes the percent yield is 33.280 g.
What is percent yield?The percent yield is the ratio of actual yield to theoretical yield. It is computed by dividing the experimental yield by the theoretical yield and multiplying the result by 100 percent. If the actual and theoretical yields are equal, the percent yield is one hundred percent.
To express the efficiency of a reaction, use the following formula: percent yield
= (actual yield/theoretical yield) x 100
= (6.26 g/ 18.81 g) x 100
= 33.280 g
Hence the correct answer is 33.280 g.
Learn more about percent yield here
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PLS HURRY TY top says "Part Two: Look at the molecules shown below. Count the number of atoms of each element and write the molecule’s formula. (You may not get the exact order of the elements in the formula, but you must have the number of atoms of each element correct.) An example has been provided. Additionally, in the boxes with an asterisk (*), write the name of the compound (from front). "
Answer: capsaicin C18 H27 NO3
Explanation: I just know the last one sorry G
Lewis acid-base concept have the following characteristics except:
A. formation of an adduct
B. formation of a coordinate covalent bond
C. donation and acceptance of an electron pair
D. donation and acceptance of a proton
Answer:
Option A) Formation of an adduct.
Explanation:
Lewis acid-base concept have the following characteristics except? Option A. Have a great day .
The Lewis acid -base concepts states that acid are electron acceptors and bases are electron donors. Hence, this concept is based on the donation and acceptance of electron pair. Thus, option C is correct.
What is Lewis acid -base concept ?According to Lewis concept of acids and bases acids are substances tends to accepts electrons and bases are electron donors. Therefore, Lewis acids are electron deficient or electrophiles.
Similarly Lewis bases are electron rich or nucleophiles. For example BF₃ is a Lewis acid and NH₃ is a Lewis base. Hence, BF₃ can accept electron from the lone pair of nitrogen from the Lewis base NH₃. and forms the acid-base pair NH₃ - BF₃.
Lewis acid- base concepts thus states the donation and acceptance of an electron pair. Hence, option C is correct.
To find more on Lewis concept, refer here:
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HELPPP ASAP 10 POINTSS
Which feature of a sound wave directly affects the pitch of the sound? (Pitch is whether it is sounds low like a rumble of thunder or high like a bird chirping)
Question 3 options:
frequency
wavelength
amplitude
longitude
Answer:
wavelength
Explanation:
Why do clouds appear and disappear?
Answer: Clouds are composed of liquid suspended water droplets in about a 100% RH environment. The three primary ways that clouds dissipate is by (1) the temperature increasing, (2) the cloud mixing with drier air, or (3) the air sinking within the cloud. Many things can increase the temperature of the cloud, like the sun, or warm air radiating off of the ground. That's why low fog and clouds tend to disappear as it warms up during the day. ... The air within the cloud descends - When the air descends, it warms.
Explanation:
determine the pH of 0.150 M KOH
Answer:
pH=12.88 i believe that's the answer
Which characteristics do stable ecosystems tend to have
Answer:
Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. Biotic factors include plants, animals, and other organisms. Abiotic factors include rocks, temperature, and humidity. Every factor in an ecosystem depends on every other factor, either directly or indirectly.
A dry, solid rock conducts electricity better than a long, meta wire.
True
False
Answer:
false
Explanation:
metal such as copper, silver, etc conducts heat and electricity. an object such as a rock, plastic, paper does NOT conduct heat.
Define trace gas in simple
this particle is an electron. it has no mass and has a negative one charge
gamma particle
alpha particle
beta particle
Answer:
The answer is a gamma particle.
Answer:
beta particle
Explanation:
If a 750 mL of a gas at a pressure of 100.7 kPa has a decrease of pressure to 99.8 kPa, what is the new volume? Show work
Explanation:
P1V1 = P2V2
(100.7 kPa)(0.75 L) = (99.8 kPa)V2
V2 = (100.7 kPa)(0.75 L)/(99.8 kPa)
= 0.757 L