Answer: (B) −198 kJ.
Type of force when you open the door. *
1 point
A. applied force
B. friction
C. gravity
D. magnetism
A. applied force
force applied to an object
Answer:
A. Applied force
Explanation:
A. should be the answer because you applied force onto an object to make it move or do what you’d like.
I hope it helps! Have a great day!
Muffin~
please I really need help
Explanation:
1) False
2) True
3) True
4) True
5) False
6) True
7) False
8) False
9) False
10) True
I hope it helps you
I'm sorry if I'm late
Select the correct answer from the drop-down menu. a scientist digs up sample of arctic ice that is 458,000 years old. he takes it to his lab and finds that it contains 1.675 grams of krypton-81. if the half-life of krypton-81 is 229,000 years, how much krypton-81 was present when the ice first formed? use the formula n = n0 . the ice originally contained grams of krypton 81.
The original mass of krypton 81 that is present in the ice is 6.70 grams.
How do we calculate original mass?Original mass of any substance will be calculated as below for the decomposition reaction is:
N = N₀(1/2)ⁿ, where
N = remaining mass of krypton-81 = 1.675g
N₀ = original mass of krypton-81 = ?
n will be calculated as:
n = T/t, where
T = total time period = 458,000 years
t = half life time = 229,000 years
n = 458,000/229,000 = 2
Now putting all these values on the above equation, we get
N₀ = 1.675 / (1/2)²
N₀ = 6.70 g
Hence required mass is 6.70 g.
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The graph above shows the titration curve that resulted when a sample of 0.1 M monoprotic acid was titrated with a solution of NaOH. Based on the graph, the pKa of the acid is closest to
(A) 3.0
(B) 4.0
(C) 6.0
(D) 8.0
(E) 12.0
Based on the titration curve of the monoprotic acid, pKa of the monoprotic acid is closest to 8.0.
What is a titration curve of acid?A titration curve of an acid is a curve obtained from the plot of the pH against the amount of base added.
The titration curve of an acid reveals its pKa.
The pKa corresponds to the midpoint of titration when equal concentrations of the acid and base have reacted.
From the titration curve above, the pKa of the monoprotic acid is closest to 8.0.
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A scientist produces zinc iodide (zni2). (a) calculate the minimum mass of zinc that needs to be added to 0.500 g of iodine so that the iodine fully reacts. the equation for the reaction is: zn + i2 ⟶ zni2 relative atomic masses (mr): zn = 65 i = 127
The minimum mass of Zinc, Zn that needs to be added to 0.500 g of iodine so that the iodine fully reacts is 0.128 g
Balanced equationZn + I₂ —> ZnI₂
Molar mass of Zn = 65 g/mol
Mass of Zn from the balanced equation = 1 × 65 = 65 g
Molar mass of I₂ = 127 × 2 = 254 g/mol
Mass of I₂ from the balanced equation = 1 254 = 254 g
SUMMARY
From the balanced equation above,
254 g of I₂ required 65 g of Zn
How to determine the mass of Zn neededFrom the balanced equation above,
254 g of I₂ required 65 g of Zn
Therefore,
0.5 g of I₂ will require = (0.5 × 65) / 254 = 0.128 g of Zn
Thus, the minimum mass of Zn required is 0.128 g
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list two examples of agroecology methods used in Burkina Faso. Dirt! The movie
Examples of agroecology method use are in Burkina Faso are conservation tillage, green manures, natural fertilisers, biological predators and so on.
What is Agroecology?Agroecology refer to an approach that use ecological processes in agricultural production systems.
The benefits of Agroecology is that it help to protect, restore and also improve agriculture and food systems when there is climate shocks and unfavorable weather conditions.
Therefore, Examples of agroecology method use are in Burkina Faso are conservation tillage, green manures, natural fertilisers, biological predators and so on.
Learn more about agroecology here.
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Freddie is carrying out an experiment for which he has to maintain a water bath at a temperature of 37°C. He has a choice of four thermometers, all of which read from 0 to 100°C.Thermometer A is marked in 5°C intervals, B in 1°C intervals, C in 10°C intervals and D in 20°C intervals. Which thermometer should Freddie choose to monitor the water bath's temperature?
B
D
A
C
Answer:
C
Explanation:
because 37 does not end with 5 or 0, so it'd be harder to see if the water temperature is accurate if your thermometer goes up by 5s or 10s. And using D, the one that goes up by 20s is out of the question, it'd be too difficult to read. Using a thermometer that goes up by 1s is just best because you can be positive when the water is at 37°C
HELPPPPP
A sample of gas contains 6 mol in a 22 L flask at 238 K. What is the pressure of the gas in atmospheres?
The pressure of the sample of gas with the given mol, volume and temperature is 5.33atm.
Ideal Gas LawThe Ideal gas law or general gas equation emphasizes on the state or behavior of a hypothetical ideal gas. It states that "pressure P times volume V is equal to moles times temperature and the universal gas constant. It is expressed;
PV = nRT
Where P is pressure, V is volume, n is the amount of substance, T is temperature and R is the ideal gas constant ( 0.08206 Latm/molK ).
Given the data in the question;
Amount of gas n = 6molVolume V = 22LTemperature T = 238KPressure P = ?We substitute our values into the expression above to determine the pressure of the gas in atmospheres.
PV = nRT
P = nRT / V
P = ( 6mol × 0.08206Latm/molK × 238K ) / 22L
P = 117.18168Latm / 22L
P = 5.33atm
Therefore, the pressure of the sample of gas with the given mol, volume and temperature is 5.33atm.
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How long is cooked steak good for in the refrigerator?.
Answer:
three to four days
Explanation:
Leftover steak is safe to eat after three to four days in the refrigerator—any longer and you could catch a foodborne illness from bacteria growth. Bacteria can also grow on perishable food that has been left out at room temperature for over two hours or kept at a temperature lower than 40°F.
What atom is the site of covalent attachment of amc to the model tetrapeptide used in the studies?.
The experiment referenced here involves the use of Y32P-ATP. The atom involved in the site of the covalent attachment is the N atom in Aminomethylcyclohexane (AMC).
The explanation in relation to the attachment of AMC to the Moel Tetrapeptide
Given that Aminomethylcyclohexane (AMC) had been linked around the carboxyl side, it, therefore, means that that type of linkage called the Amide-Linkage (That is N-acylation) can be utilized in the covalent bonding of the fluorophore into the peptide
See the link below for more about Covalent Attachements:
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which molecule can't be exist?
A)NCl3 B)OF6 C)ONF3 D)PCl3
Answer:
OF6
Explanation:
Oxygen and fluorine have almost the same electronegativity, so oxygen isn't able to donate enough electron density to fluorine to form OF6. Atomic size. There isn't enough room around an oxygen atom for six fluorine atoms.
:-befrank
1. A sample of air has a volume of 140.0 mL at 273 K. To what temperature must the
gas be lowered to reduce its volume to 50.0 mL, at a constant pressure?
Explanation:
The question had been answered above
how many moles of o2 would be required to produce 4 mol h2o?
Hii there !
The reaction accompanying production of water in this case would be -
[tex]\green{ \underline { \boxed{ \sf{2H_2+O_2\longrightarrow 2H_2O}}}} [/tex]
Thus ,by observing the reaction, we can conclude that 2 mole of Hydrogen [tex](H_2 )[/tex]react with 1 mole of oxygen[tex](O_2)[/tex]to produce 2 mole of water [tex](H_2O)[/tex]
Now,
To produce 1 moles of water.
Moles of Oxygen[tex](O_2)[/tex] required [tex] = \frac{1}{2}[/tex] moles
Similarly,
To produce 4 moles of water.
[tex]\implies[/tex] Moles of Oxygen[tex](O_2)[/tex] required = [tex]\frac{1}{2}\times 4[/tex] moles
[tex]\implies[/tex] 2 moles
Hope it helps.
If y’all can answer this I’ll give you’ll some extra points
From observing the reaction, what would you predict to be delta H and delta S for the hydration of CaO? Warning. This is a tricky question. To help you determine the correct answer, the chemical reaction involving CaO and water is written below. Remember to us the rules you learned about assigning the sign of delta S
2CaO(s) + H2O(l) —> 2Ca(OH)2(s)
Based on the nature ofbthe reaction, entropy (ΔS) increases while enthalpy (ΔH) decreases.
What are entropy and enthalpy changes?Entropy changes, ΔS, refers to change in the degree of the disorderliness of a substance.
When substances become more random, entropy increases and vice versa.
For example, change of state from solid to liquid or gas results in increase in entropy.
Enthalpy changes, ΔH, refers to the changes in heat content of a substance, either a decrease or increase.
Enthalpy is negative when heat is lost and positive ehen heat is gained.
The enthalpy and entropy changes in the given reaction below is as follows:
2CaO(s) + H2O(l) —> 2Ca(OH)2(s)
Entropy, ΔS increases as the substance dissolves in water.
Enthalpy, ΔH, decreases as the substances gives off heat.
Therefore, in the given reaction entropy (ΔS) increases while enthalpy (ΔH) decreases.
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just pick the right option
Answer:
A
Explanation:
As CO₂ (carbon dioxide) depends on the air temperature, it is the dependent variableTherefore, air temperature is the independent variableThis is about the relation between carbon dioxide and air temperature, so the soil surface is not a variable to be consideredWhat is a DNA fingerprint and why is it considered individual evidence?
Answer:
DNA fingerprinting is a laboratory technique used to establish a link between biological evidence and a suspect in a criminal investigation.
A DNA sample taken from a crime scene is compared with a DNA sample from a suspect. If the two DNA profiles are a match, then the evidence came from that suspect.
How are dams and levees alike?
Answer:
they are bigg has water in then and they a deep
HELP PLS DUE TODAY
Biotechnology Activity
Now that you are more familiar with the benefits, risks, and impacts of biotechnology, it is time for you to take a stand! Your task is to choose one of the following types of biotechnology: genetic engineering, cloning, or artificial selection.
You will then write a one- to two-paragraph summary describing your chosen type of biotechnology. You will then need to argue for either the benefits or the risks of your chosen type. Your arguments should present your position, and then give the evidence that led you to this position. Be sure to include the following in your argument:
a description of your chosen type of biotechnology (genetic engineering, cloning, or artificial section)
one benefit or one risk for the individual (based on whether you are for or against it)
one benefit or one risk for society (based on whether you are for or against it)
one benefit or one risk for the environment (based on whether you are for or against it)
A picture (you may hand draw, take photos in nature, or use stock images)
Answer: Ok
Explanation: Explanation:Using recombinant DNA technology to modify an organism's DNA to achieve desirable traits is called genetic engineering. Addition of foreign DNA in the form of recombinant DNA vectors that are generated by molecular cloning is the most common method of genetic engineering.
If you want to produce 18.48 grams of NaCl what is the minimum amount of each reactant that you must start with
The minimum amount of NaOH and HCl that must be present to produce 18.48grams of NaCl is 12.6g and 11.5g respectively.
Calculation of amount of reactantsThe balanced neutralization reaction equation for the formation of NaCl is,
NaOH + HCl ---> NaCl + H2
The molar mass of NaOH = 23+16+1 = 40g/mol
The molar mass of NaCl = 23 +35.5 = 58.5g/mol
If 40g of NaOH = 58.5g of NaCl
∴ x g of NaOH = 18.48g of NaCl
Make xg the subject of formula,
x g of NaOH = 40 × 18.48/58.5
= 739.2/58.5
= 12.6g of NaOH
The molar mass of HCl = 1 +35.5 = 36.5g/mol
If 36.5g of HCl= 58.5g of NaCl
∴ x g of HCl = 18.48g of NaCl
Make xg the subject of formula,
x g of HCl = 36.5 × 18.48/58.5
= 674.52/58.5
= 11.5g of HCl
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Consider the following reactions Ca(OH)2 + 2NH4Cl - Cacl2 + 2H₂O + 2NH2 a) how many grams of cacl2 will be formed from the if . 1)40 gram of nh4cl?
Answer:
41.495
Explanation:
107 gm of 2NH4Cl gives 111 gm of CaCl2
40 gm of 2 NH4Cl gives =(111*40)/107
=41.495 gm of CaCl2
Explain why you usually can’t use just a single spectral line to confirm the identity of an element.
You can't usually just use a single spectrum line to confirm the identity of an element because there are cases that the emission line id not clearly defined. When the emission line is very weak compared to surrounding noise, in which case the more datapoints you have to build up confidence for the existence of a particular emission spectra, the better.
In the Lewis symbol for a fluorine atom, there are __________ paired and __________ unpaired electrons.
In the Lewis symbol for a fluorine atom, there are 4 paired and 1 unpaired electrons.
However, paired electrons simply means are 2 electrons occupying the same orbital in an atom or molecule of a substance
On the other end, unpaired electron is a single electron that occupies an orbital of an atom.
What is an atom?An atom is the smallest part of an element which can take part in a chemical reaction.
Some atoms of elements are:
MonoatomicDiatomicTriatomicPolyatomicIn conclusion, in the Lewis symbol for a fluorine atom, there are 4 paired and 1 unpaired electrons.
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Answer: 6, 1
Explanation:
Time (sec) [CH4] (mol/L)
0 1.2
20 1.0
40 0.9
60 .85
CH4 (g) + O2 (g) -----> CO2 (g) + H2O (l)
Given the above table and equation above, calculate the average rate of consumption of oxygen from time 20 seconds to time 60 seconds.
Based on the table and the equation of reaction; the
rate of consumption of oxygen between time 20 and 40s is 0.005 M/srate of consumption of oxygen between time 40 and 60s is 0.0025 M/sWhat is rate of a reaction?The rate of a reaction is the rate at which reactants molecules are consumed or products are formed.
Rate of reaction = change in concentration of reactants or products/ time takenBased on the equation of reaction, the rate of consumption of oxygen is equal to the rate of consumption of methane.
Thus. rate of consumption of oxygen from time 20 seconds to time 60 seconds is calculated as follows:
Rate between 20 and 40 = 1.0 - 0.9/20
Rate of consumption of oxygen = 0.005 M/sRate between 40 and 60 = 0.9 - 0.85/20
Rate of consumption of oxygen = 0.0025 M/sTherefore, the rate of consumption of oxygen decreases with time.
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1. Describe what the following terms mean
Temperature -
Heat -
Exothermic -
Endothermic -
HELP PLS (IT IS NOT THE THIRD ONE)
Answer:
A. would be your answer
Explanation:
Decomposers are especially important in retaining nutrients in their cells thus preventing loss of those nutrients from the root zone.
In an ecosystem, the decomposing web is important because decomposers help remove waste and use that energy to provide food for other animals.
What is an ecosystem?An ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the ecosystem through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass which is present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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#SPJ7
Select all of the following which are Nitrogenous bases that make up DNA:
a)Glutamine
b)Thymine
c)Adenine
d)Thyrine
e)Guanine
f)Cytosine
Answer:
adenine (A, green), thymine (T, red), cytosine (C, orange), and guanine (G, blue).
Explanation:
The nitrogen bases in a DNA molecule are adenine, guanine, cytosine, and thymine. Adenine and guanine belong to a class of compounds called purines, and cytosine and thymine belong to a class of compounds called pyrimidines. In a DNA molecule, the two strands are connecting by hydrogen bonds between the nitrogen bases of each strand. According to the base-pairing rule, the purine adenine always pairs with the pyrimidine thymine, and the purine guanine always pairs with the pyrimidine cytosine...
Summarize: If you know the RGB values of two colors of light, how could you calculate the RGB value of a mixture of the two colors? _______________________________________
_________________________________________________________________________
What does net force depend on
Answer:
net force depends upon the object and also the mass of that object
Answer:The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object.
Explanation:
Select all that apply.
Which items are properties of acids?
soapy
sour
sweet
sharp
possible burns
for 10 points
Answer:
Sour and Possible Burns
Explanation:
Bases are soapy, not acids.
All acids are sour to taste.
Neither bases nor acids are sweet.
Sharp is a physical trait for things such as knives, not acidic liquids.
Acids can cause burns if handled incorrectly.
what are two basic properties of the gas phase
Answer:
It has no definite shape or volume.
