A radioactive element has a half- life of 2 days. Which fraction represents the amount of an original sample of this element remaining after 6 days?
Answer : The fraction represents the amount of an original sample of this element remaining after 6 days is [tex]\frac{1}{8}[/tex] .
Explanation :
Half-life = 2 days
Time = 6 days
Formula used:
[tex]N=N_o\times (\frac{1}{2})^{(\frac{t}{t_{1/2}})}[/tex]
where,
N = final amount
[tex]N_o[/tex] = initial amount
t = time
[tex]t_{1/2}[/tex] = half-life
Now putting all the given values in the above formula, we get:
[tex]N=N_o\times (\frac{1}{2})^{(\frac{6}{2})}[/tex]
[tex]\frac{N}{N_o}=(\frac{1}{2})^{(\frac{6}{2})}[/tex]
[tex]\frac{N}{N_o}=(\frac{1}{2})^3[/tex]
[tex]\frac{N}{N_o}=\frac{1}{8}[/tex]
Therefore, the fraction represents the amount of an original sample of this element remaining after 6 days is [tex]\frac{1}{8}[/tex] .
3. What are the products of the following reaction?
H2SO4 + KOH --> *
A) H2 + K2904
B) H2O + K2SO4
C) HK + HSO4
D) H2O + KS04
Answer:
H2SO4 + 2KOH -------> K2SO4 + 2H2O
Explanation:
Which of the following is the most accurate definition of heredity?
A. The storage of information in the nucleus of every cell in the body
B. The passage of genetic instructions from one generation to another
C. The relationship of one organism to another by evolutionary history
D. The adaptation of an organism for better survival in a new habitat
Answer:
The passage of genetic instructions from one generation to another
Explanation:
The one that is most accurate definition of heredity is the passage of genetic instructions from one generation to another. The correct option is B.
What is the reason behind heredity?Heredity, also known as inheritance or biological inheritance, is the transmission of traits from parents to their offspring; the offspring cells or organisms acquire the genetic information of their parents through reproduction.
Genes are composed of DNA (deoxyribonucleic acid), which contains instructions for cell function as well as the characteristics that distinguish you.
Each biological parent gives you half of your genes, and you may inherit a gene mutation from one or both of your parents. Sometimes genes change as a result of problems with the DNA (mutations).
Hereditary theory holds that many physical characteristics can be passed down from generation to generation via DNA, by passing on a set of instructions or genes in DNA to offspring. You pass on the physical characteristics that you have.
Thus, the correct option is B.
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Do Covalent bonds have weaker or stronger chemical bonds than Ionic bonds?
Ionic bonds are stronger than covalent bonds since they are of opposite charges. This makes them more attracted to each other, creating bonds that are harder to break. Covalent bonds don't have this and only occur to share electrons between atoms.
I hope this helps!
when aqueous solutions of sodium hypochlorite and nitric acid are mixed, an aqueous solution of sodium nitrate and hypochlorous acid results. Write the net ionic equation for the reaction.
Answer:
H+ (aq) + ClO- (aq) ---> HClO(aq)
Explanation:
The net ionic reaction equation is a chemical equation that explicitly shows only the particular ions that undergo a chemical change in the course of a given reaction.
In this particular reaction, the molecular reaction equation is shown as follows;
HNO3(aq) + NaOCl(aq) -----------> NaNO3(aq) + HOCl(aq)
Ionically;
H+ (aq) + ClO- (aq) ---> HClO(aq)
Hurry it’s for a test!! The arctic fox and gray wolf are two examples of
animals that change the color of their fur with the
seasons. In the summer, the animals are a brownish
color, and in the winter, they turn white. The
change of color helps the animals to survive.
Which of the following provides the best explana-
tion for this change?
A The color change helps them raise their young.
B The color change helps protect them from
predators.
The color change helps them be seen from a
great distance.
D The color change helps them regulate their
body temperature better.
Classify the following alcohol as primary secodary or tertiary
CH3CH2CH2OH
Answer:
The answer would be letter A
Explanation:
The answer is primary
There are three types of alcohol one is primary second is secondary and third is tertiary. Therefore, the given alcoholic compound CH[tex]_3[/tex]CH[tex]_2[/tex]CH[tex]_2[/tex]OH is a primary alcohol.
What is alcohol?Alcohol is a chemical molecule with a functional group called hydroxyl linked to a saturated carbon atom.
Alcohols classified as primary have just one alkyl group on which the carbon atom of the hydroxyl group (OH) is connected. Secondary alcohols are those that have two alkyl groups on either side of the carbon atom of the hydroxyl group. In tertiary alcoholic group, the carbon that is bonded to hydroxyl group is bonded to three alkyl groups. the given alcoholic compound CH3CH2CH2OH is a primary alcohol.
Therefore, the given alcoholic compound CH3CH2CH2OH is a primary alcohol.
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An force results when one force is stronger than other forces
and the motion of an object is affected
When two equal forces act in opposite directions the result is that the forces are balanced and there is no motion. The process of moving or changing position. When one force is stronger than the other the result is motion.
An force results when one force is stronger than other forces and the motion of an object is affected is unbalanced force.
What is force?A force is an influence in physics that can change the motion of an object. A force can cause a mass object to change its velocity, or accelerate.
The forces are balanced if the people on each side of the rope pull with equal strength but in opposite directions.
As a result, there is no movement. Forces that are in balance can cancel each other out. The object does not move when there is a balanced force.
Forces out of balance, If one force is stronger than the others and their effects do not cancel out, the forces are unbalanced. Unbalanced forces alter motion, speed, and/or direction. A greater force results in a greater change in motion.
Thus, the answer is unbalanced force.
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Which process causes earth surface to warm
Plzzzzzzzzzzz helpppppp
Answer:
True
Explanation:
If someone's genetics were Bb, B would be the dominant trait and b would be the recessive trait.
Answer:
True
Explanation:
That's how it works
Which of the following plant structures provides most of the water necessary for photosynthesis?
а. roots
b. leaves
chloroplasts
d. stomata
Answer:
Explanation:
a:)
The plant structure that provides most of the water necessary for photosynthesis is the leaves. The correct option is b.
What is photosynthesis?Through a process known as photosynthesis, green plants and some other animals transform light energy into chemical energy. The main, readily available, non-recyclable component of photosynthesis is sunlight.
Plants use their roots to draw water from the soil. Water is necessary for photosynthesis, which primarily takes place in a plant's leaves, as you probably already know.
Chloroplasts, which are found in the mesophyll of the leaves, are where photosynthesis occurs. The chlorophyll in the thylakoids, which are located inside the chloroplast, absorbs the various colors of light to produce energy.
Therefore, the correct option is b. leaves.
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( urgent help needed!! 50pts + brainliest )
What particle remains when uranium-238 undergoes alpha decay?
A. thorium-234
B. protactinium-234
C. plutonium-234
D. neptunium-234
Answer:
Thorium-234 option a .......
238 4 234
U --> α + Th
92 2 90
The answer is A Thorium.
How many neutrons are contained in nitrogen -15?
Answer:
7 neutrons
Explanation:
The raw water supply for a community contains 18 mg/L total particulate matter. It is to be treated by addition of 60 mg alum (Al2(SO4)3 14H2O) per liter of water treated. Essentially, all the added alum precipitates represented by the following reaction:
Required:
a. For a total flow of 8000 m^3/d, compute the daily alum requirement and the concentration of solids in the water following alum addition, assuming the alum all precipitates as Al(OH)3(s).
b. The water is initially at pH 7.5 and has ALK=40 mg/L as CaCO3. It is desired to maintain solution pH at 6.5 or higher. Will the pH be in the acceptable range after the chemical addition and Al(OH)3(s) precipitation?
c. What will the pH be if the treated solution is bubbled with air, so that it reached equilibrium with atmospheric CO2?
Solution :
Given :
The steady state flow = 8000 [tex]$ m^3 /d $[/tex]
[tex]$= 80 \times 10^5 \ I/d $[/tex]
The concentration of the particulate matter = 18 mg/L
Therefore, the total quantity of a particulate matter in fluid [tex]$= 80 \times 10^5 \ I/d \times 18 \ mg/L $[/tex]
[tex]$= 144 \times 10^6 \ mg/g$[/tex]
[tex]$= 144 \ kg/d $[/tex]
If 60 mg of alum [tex]$ [Al_2(SO_4)_3.14 H_2O] $[/tex] required for one litre of the water treatment.
So Alum required for [tex]$ 80 \times 10^5 \ I/d $[/tex]
[tex]$= 80 \times 15^5 \ I/d \times 60 \ mg \ alum /L$[/tex]
[tex]$= 480 \times 10^6 \ mg/d $[/tex]
or 480 kg/d
Therefore the alum required is 480 kg/d
1 mg of the alum gives 0.234 mg alum precipitation, so 60 mg of alum will give [tex]$ = 60 \times 0.234 \text{ of alum ppt. per litre} $[/tex]
[tex]$= 14.04 $[/tex] mg of alum ppt. per litre
480 kg of alum will give = 480 x 0.234 kg/d
= 112.32 kg/d ppt of alum
Daily total solid load is [tex]$= 144 \ kg/d + 112.32 \ kg/d$[/tex]
= 256.32 kg/d
So, the total concentration of the suspended solid after alum addition [tex]$= 18 \ mg/L + 60 \times 0.234 $[/tex]
= 32.04 mg/L
Therefore total alum requirement = 480 kg/d
b). Initial pH = 7.4
The dissociation reaction of aluminium hydroxide as follows :
[tex]$Al(OH)_3 \rightleftharpoons Al^{3+} + 3OH^{-} $[/tex]
After addition, the aluminium hydroxide pH of water will increase due to increase in [tex]$ OH^- $[/tex] ions.
Therefore, the pH of water will be acceptable range after the addition of aluminium hydroxide.
c). The reaction of [tex]$CO_2$[/tex] and water as follows :
[tex]$CO_2 (g) + H_2O (l) \rightarrow H_2CO_3$[/tex]
For the atmospheric pressure :
[tex]$p_{CO_2} = 3.5 \times 10^{-4} \ atm $[/tex]
And the pH is reduced into the range of 5.9 to 6.4
Please help me thanks so much....I’ll mark you?!?!:)))) ( 32 points)
Answer:
I believe it's chemical
Answer:
physical
Explanation:
it's not changing form or substance
Differentiate between a mixture and a compound. Provide an example of each using the characteristics outlined in the lesson to support your example.
Explanation:
A compound is a pure substance formed by the combination of two or more kinds of atoms or elements joined together in a definite grouping.
An mixture is an impure substance made up of different types of substances.
Here are some of the differences between them;
A compound is a pure substance whereas a mixture is an impure substance. All parts of a compound are homogenous throughout where a mixture is often heterogeneous. Compounds have definite compositions whereas mixtures do not have a definite composition. Compounds cannot be easily broken down by physical means whereas in mixtures, separation is by physical means. Compound have a unique set of physical properties whereas mixtures have varied set of physical properties.Examples of compounds are water, sodium chloride, hydrochloric acid
Mixtures are air, ocean water, alloys, et.c
Which of the following are indicators of a chemical change select all that apply
Answer: 1.color change
2.temperature change
3. precipitate formation
4.gas formation
Explanation: There is no pic
Is the enzyme lactase a catalyst? why or why not?
Answer:
Explanation:
The enzyme lactase acts as a catalyst to facilitate the reaction and make it happen very quickly. This enzyme is made u.
do the rest
hope it helps
Enzyme lactase catalyzes the hydrolysis of the glycosidic bond of lactose to form galactose and glucose.
What is lactase?Lactase can be described as an enzyme produced by many organisms. Lactase is located in the small intestine of humans and other mammals. It is essential to accomplish the digestion of milk and it breaks down lactose that gives milk its sweetness.
A person with a deficiency of lactase, and who consume dairy products, may experience the symptoms of lactose intolerance. Lactase is a part of the β-galactosidase family of enzymes and is a glycoside hydrolase involved in the hydrolysis of lactose into constituent galactose and glucose monomers.
The β-glycosidic bond in D-lactose in metabolism is hydrolyzed to form D-galactose and D-glucose, which can be absorbed into the bloodstream. The optimum temperature of the human lactase is about 37 degrees Celcius and the optimum pH of the human lactase is equal to 6.
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Aqueous solutions of Na2CO3 and Ca(NO3)2, 0.10 M each, are combined. A white precipitate is observed in the container after mixing. The precipitate is filtered and carefully rinsed with distilled water to remove other ions. A sample of the precipitate is added to 100 mL of 0.1 M NaCl. A second sample of the precipitate is then added to 100 mL of 0.1 M HCl. What would be observed in each case
The question is incomplete. Here is the complete question.
Aqueous solutions of [tex]Na_{2}CO_{3}[/tex] and [tex]Ca(NO_{3})_{2}[/tex], 0.10 M each, are combined. A white precipitate is observed in the container after mixing. he precipitate is filtered andcarefully rinsed with distilled water to remove other ions. A sample of the precipitate is added to 100 mL of 0.1 M NaCl. A second sample of the precipitate is then added to 100 mL of 0.1 M HCl. What would be observed in each case?
Observation upon Observation upon
addition of precipitate addition of precipitate
to NaCl(aq) to HCl(aq)
(A) additional precipitates forms no visible reaction occurs
(B) no visible reaction occurs gas is produced and some precipitate dissolves
(C) no visible reaction occurs no visible reaction occurs
(D) additional precipitates forms gas is produced and some
precipitate dissolves
Answer: (B) No visible reaction occurs; Gas is produced and some precipitate dissolves
Explanation: When aqueous solutions of [tex]Na_{2}CO_{3}[/tex] and [tex]Ca(NO_{3})_{2}[/tex] are combined, it reacts according to the following balanced equation:
[tex]Na_{2}CO_{3}+Ca(NO_{3})_{2}[/tex] → [tex]CaCO_{3}_{(s)}+2NaNO_{3}_{(aq)}[/tex]
forming calcium carbonate ([tex]CaCO_{3}[/tex]), which, as it is insoluble in water, precipitates as a solid of the color white. This process is Precipitation and this reaction is a Precipitation Reaction.
When calcium carbonate reacts with NaCl it produces:
[tex]CaCO_{3}+2NaCl[/tex] → [tex]CaCl_{2}+Na_{2}CO_{3}[/tex]
Now, calcium chloride is an inorganic compound very soluble in water, so, in this reaction, there are no precipitate and no visible reaction occurs.
When [tex]CaCO_{3}[/tex] reacts with hydrochloridric acid, the balanced reaction is
[tex]CaCO_{3}+2HCl[/tex] → [tex]CaCl_{2}+H_{2}CO_{3}[/tex]
which, also produces calcium chloride and carbonic acid.
Both are soluble in water but, when carbonic acid is in an "aqueous state", carbonic acid, it dissociates, forming carbon dioxide and water. Therefore, gas is produced and some precipitate dissolves.
In conclusion, sentence B is the correct alternative.
What does point of view refer to?
the purpose of whoever is telling the story
the age of whoever is telling the story
the perspective of whoever is telling the story
Answer:
I'd say the most reasonable answer is perspective.
Explanation:
"Point of view" is about who is telling and sharing the details in what you are writing or reading. I'm not 100% sure because the word "perspective" doesn't seem like the right word to use, but it's better than the other two in my opinion.
Suppose 2.27g of lead(II) nitrate is dissolved in 300.mL of a 52.0mM aqueous solution of ammonium sulfate. Calculate the final molarity of nitrate anion in the solution. You can assume the volume of the solution doesn't change when the lead(II) nitrate is dissolved in it.
Answer:
0.0457M is molarity of nitrate anion in the solution.
Explanation:
Molarity is defined as the ratio between moles of solute (In this case, nitrate ion) and liters of solution (The total volume of the solution is 300.0mL = 0.300L).
Thus, we need to convert mass of Lead(II) nitrate to moles using its molar mass (Molar mass Pb(NO₃)₂: 331.2 g/mol). Moles of Pb(NO₃)₂ = 1/2 Moles of NO₃⁻:
Moles Pb(NO₃)₂ and moles of NO₃⁻:
2.27g * (1mol / 331.2g) = 0.006854 moles Pb(NO₃)₂ * (2moles NO₃⁻ / 1mol Pb(NO₃)₂) = 0.0137moles NO₃⁻
Molarity is:
0.0137 moles NO₃⁻ / 0.300L =
0.0457M is molarity of nitrate anion in the solutionWhat is a renewable energy source that is captured using the heat of the Earth? I need quick answers so please answer ASAP.
Explanation:
Geothermal energy
A leak in the air conditioning of an old car releases Chlorofluorocarbons (CF2C\2) into the air.
Each month the car releases 62g of CF2Cl2. How much fluorine is emitted into the air each
YEAR by this car?
Answer:
[tex]m_F=234gF[/tex]
Explanation:
Hello!
In this case, given that one molecule of CF2Cl2 contains two moles of atoms of fluorine, we can set up the following dimensional analysis to compute the emitted fluorine each year by the considered car:
[tex]m_F = \frac{62gCF_2Cl_2}{1month}*\frac{12months}{1year}* \frac{1molCF_2Cl_2}{120.91gCF_2Cl_2}*\frac{2molF}{1molCF_2Cl_2} *\frac{19.0gF}{1molF} \\\\m_F=234gF[/tex]
Best regards!
i need help ......................................
Answer
One of them is a Solid and one of them is a liquid and the other one is air
Explanation:
g Does a reaction occur when aqueous solutions of chromium(III) sulfate and ammonium phosphate are combined
Answer:
See explanation
Explanation:
The reduction potential of Cr III is more negative than that of NH4+ hence NH4+ will be displaced by Cr III from a solution of its salt according to the following reaction equation;
Cr2(SO4)3 + 2(NH4)3PO4--------->2CrPO4 + 3(NH4)2(SO4)
Hence;
A reaction occurs when aqueous solutions of chromium(III) sulfate and ammonium phosphate are combined.
what is the basic principle of chromatography process
process by which one separates compounds from one another by passing a mixture through column that retains some compounds longer than others.
The _______________ react with the _______________ elements to form different compounds like lithium fluoride (LiF) and sodium chloride (NaCl). _______________ have a full valence level and do not combine with other elements.
Answer: Alkali metals, halogens, noble gases
Explanation:
Ionic compounds are made of ions- charges. In LiF and NaCl, the first element has a +1 and the second element has a charge of -1. Elements that are +1 are alkali metals and elements that are -1 are halogens. Noble gases have full octets in their outermost valence shell, and since they're full it's so stable so it doesn't react with anything.
What is the function of mitochondria in plant and animal cells?
A
It receives and removes wastes.
B
It functions in making RNA and DNA.
C
It is the location of cellular respiration and produces ATP.
D
It provides a barrier between the inside and the outside of the cell.
An example of a chemical change A. Fireworks B. Chemical reaction C. Chemical change D. Energy
What type of energy does the
mitochondrion provide the cell?
chemical energy (ATP)
light energy
thermal energy
sound energy
The answer is multiple choice
Answer:
Thermal
Explanation:
I think im not quite sure but since thermal is basically heat energy, I assume it would be thermal energy
