Answer:
14 hrs.
Explanation:
From the question given above, the following data were obtained:
Time (t) = 42 hrs
Original amount (N₀) = 4.32 g
Amount remaining (N) = 0.54 g
Half-life (t½) =…?
Next, we shall determine number of half-lives required for 4.32 g of the isotope to decay to 0.54 g. This can be obtained as follow:
Original amount (N₀) = 4.32 g
Amount remaining (N) = 0.54 g
Number of half-lives (n) =?
N = 1/2ⁿ × N₀
0.54 = 1/2ⁿ × 4.32
Cross multiply
0.54 × 2ⁿ = 4.32
Divide both side by 0.54
2ⁿ = 4.32 / 0.54
2ⁿ = 8
Express 8 in index form with 2 as the base
2ⁿ = 2³
n = 3
Thus, it took 3 half lives for 4.32 g of the isotope to decay to 0.54 g.
Finally, we shall determine the half-life of the isotope. This can be obtained as follow:
Time (t) = 42 h
Number of half-lives (n) = 3
Half-life (t½) =
n × t½ = t
3 × t½ = 42
Divide both side by 3
t½ = 42 / 3
t½ = 14 hrs
Thus, the half-life of the isotope is 14 hrs
Atoms of which element can bond to each other to form chains, rings, and networks?
Select one:
O a. hydrogen
b. oxygen
c. chlorine
d. carbon
A forest area is being used for a new housing development. Most of the trees have been removed to make room for the
new houses, Predict the impact that this will have on the birds in the area.
Answer:
The correct answer would be - lose their native habitats are forced to migrate into new areas in search of shelter and food.
Explanation:
The removal of trees or deforestation to build a housing or city planning or development impact the birds and other animals of that area. Cutting most of the trees from the area will result in a decrease in available food, shelter, and breeding habitat.
It causes complete removal of bird species and forced them to migrate to a new place in search of places that will provide a source of shelter and food for birds.
Which actions will change an object’s weight, but not it’s mass?
A. Breaking the object
B. Compressing the object
C. Immersing the object in water
D. Placing the object on a different planet
PLZ HELP
Answer:
D
Explanation:
The weight of an object will change if the object is brought farther away from Earth, or placed on a different planet since the force of gravity on the object will change. However, the mass of the object will remain the same regardless of whether the object is on Earth, in outer space, or on the Moon. hope this helps have a good day :)
A thermometer containing 8.3 g of mercury has broken. What volume, in milliliters, of mercury spilled?
The volume of Mercury spilled : 0.613 milliliters
Further explanationGiven
8.3 g of Mercury
Required
The volume
Solution
Density is a quantity derived from the mass and volume
Density is the ratio of mass per unit volume
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
Density of mercury : 13.534 g/cm³
Input the value :
V = m : ρ
V = 8.3 g : 13.534 g/cm³
V = 0.613 cm³= 0.613 ml
Use the information to calculate deltaGrxn at 298 K. 3H2(g) +N2(g) 2NH3(g) deltaHrxn = -92.38 deltaSrxn =-198.2 J/K deltaGrxn = ___kJ
Answer:
-33.3 kj
Explanation:
Answer:
first part = - 2453.1
second part = - 33.3
Explanation:
edg 22
How many significant digits are in 1,000,005 micrometers
Answer:
7
Explanation:
not including the comas but if you add 4+3 it equals 7.
Answer:
7 significant figures
Explanation:
H2(g)+p4(s)ph3(g) what the answer ?
Answer:
6H2 + P4→ 4PH3
Explanation:
Phosphorus has 4 in it and hydrogen has 3 in it. in order to balance it, we have to put 4 in front of phosphine so that the phosphorus on the product side has an equal amount as to the one on the reactant side.
the only one left to balance is hydrogen and so in order to balance it we put a 6 on h2 because the hydrogen in the product size becomes 12 (4 * 3).
therefore the hydrogen on the reactant side becomes 12 as well (6 * 2)
The balanced chemical reaction is:
[tex]6H_2(g)+P_4(s)\rightarrow 4PH_3(g)[/tex]
Explanation:
In a balanced chemical equation number of atoms of all the elements are equal on the reactant side and product side.The given equation of the chemical reaction is not balanced.[tex]H_2(g)+P_4(s)\rightarrow PH_3(g)[/tex]
Balancing the chemical reaction:
Balance the atoms of all the elements besides hydrogen and oxygen. Balance phosphorus atoms by writing 4 in front of phosphine gas on the product side.[tex]H_2(g)+P_4(s)\rightarrow 4PH_3(g)[/tex]
Now balance the hydrogen atoms. There are 12 hydrogen atoms on the product side and 2 hydrogen atoms on the reactant side. So by writing 6 in front of hydrogen gas on the reactant side.[tex]6H_2(g)+P_4(s)\rightarrow 4PH_3(g)[/tex]
So, the balanced chemical reaction is:
[tex]6H_2(g)+P_4(s)\rightarrow 4PH_3(g)[/tex]
Learn more about the balanced chemical reaction here:
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How many moles of magnesium chloride are produced when 4.39 moles of magnesium are placed in a beaker
containing only 250.0 grams of hydrochloric acid?
Answer:
[tex]n_{MgCl_2}=3.43mol MgCl_2[/tex]
Explanation:
Hello!
In this case, since the reaction between magnesium and hydrochloric acid is:
[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]
Whereas there is a 1:1 and 1:2 mole ratio between magnesium and magnesium chloride and hydrochloric acid and magnesium chloride respectively; it is possible to compute the yielded moles of product by each reactant and then determine which moles are correct based on the limiting reactant; therefore, we proceed as follows:
[tex]n_{MgCl_2}^{by\ Mg}=4.39molMg*\frac{1molMgCl_2}{1molMg} =4.39molMgCl_2\\\\n_{MgCl_2}^{by\ HCl}=250.0gHCl*\frac{1molHCl}{36.46gHCl}*\frac{1molMgCl_2}{2molHCl}=3.43mol MgCl_2[/tex]
Thus, since the hydrochloric acid yields the fewest moles of product, we infer it is the limiting reactant, so the correct number moles of magnesium chloride are 3.43 mol.
Best regards!
A student titrates 0.2087 g of an unknown diprotic acid with 0.1224 M sodium hydroxide. It takes 32.47 mL of the NaOH solution to reach the endpoint. How many moles of NaOH are used in the titration
Given :
A student titrates 0.2087 g of an unknown diprotic acid with 0.1224 M sodium hydroxide.
It takes 32.47 mL of the NaOH solution to reach the endpoint.
To Find :
How many moles of NaOH are used in the titration.
Solution :
Number of moles( n ) is given by :
n = Molarity × Volume( in liters )
n = [tex]0.1224 \times \dfrac{32.47}{1000}\ moles[/tex]
n = 0.00397 moles.
Therefore, moles of NaOH are used in the titration is [tex]3.97\times 10^{-3} \ moles[/tex].
The number of moles of NaOH are used in the titration is [tex]3.97 \times 10^{-3}[/tex] moles.
The calculation is as follows;The number of moles should be
[tex]= molarity \times volume\\\\= 0.1224 \times \frac{32.47}{1000}[/tex]
= 0.00397 moles.
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What is the Scientific notation for 0.10050
Answer:
1.005 x [tex]10^{1}[/tex]
Explanation:
A 1500 kg race car accelerates at a rate of about 9M /s2 as to how much force does the engine need to create for this to happen
Answer:
13500 N
Explanation:
According to newtons second law of motion
mass m =1500 Kg
a = 9m/s^2
Force F = mass m × acceleration a
F = 1500×9= 13500 N
What type of heat transfer occurs when you touch a metal seat with your
hand and the seat feels cold?
A. Radiation
B. Convection
C. Conduction
D. Transportation
How many joules of heat are absorbed when 10.00 grams of water is completely vaporized at its boiling
point?
Answer:158.2 J
Explanation: Use your equations and fill in
A sample of carbon dioxide gas that has a volume of 14.6 L at STP contains how many
mol(s) of gas (to three significant figures).
Answer:
n = 0.651 mol
Explanation:
Given data:
Volume of CO₂ = 14.6 L
Temperature = standard = 273.15 K
Pressure = standard = 1 atm
Number of moles of CO₂ = ?
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
by putting values,
1 atm × 14.6 L = n × 0.0821 atm.L/ mol.K × 273.15 K
14.6 L. atm = n × 22.43atm.L/ mol
n = 0.651 mol
When a strong acid and a strong base react completely, what is the resulting pH? (numerical value only)
Answer:
i think the answer is 7
Explanation:
Hope this is it
How many moles are in 4.30 grams of lead (Pb) ?
Answer:0.005 moles
Explanation: 4.3/207 moles = 0.005
Describe how the weight of an objects influences that objects shape or design to support that weight.
(Hint: We described the legs of different sized animals. We also described the architecture of ancient buildings like the pyramids)
Answer:
The weight of the objects has a name and is "Specific weight", this is measured in several measurements but the best known is the kg.
If we relate the density of the object with the weight we will obtain a deduction of the shape of the object.
Explanation:
The object can be more or less heavy according to its density and its chemical composition.The weight is nothing more than the attraction of that object with the interior of the earth, that is why in order to know well how heavy it is, it is necessary relate the density of the object, the material that composes it, the speed of gravity (10m / s2).
This refers to the fact that a kilo of feather is not the same as a kilo of lead, each object obtains its shape according to the more weight it has and the more attraction it can make to the center of the earth.
6)
How many joules of heat energy must be added to 5 grams of liquid water to change its
temperature from 10°C to 30°C?
A)
83.6 joules
B)
100 joules
C)
312.6 joules
D)
418 joules
Answer:
D) 418 J
Explanation:
Step 1: Given and required data
Mass of water (m): 5 gInitial temperature: 10 °CFinal temperature: 30 °CSpecific heat capacity of water (c): 4.184 J/g.°CStep 2: Calculate the temperature change (ΔT)
ΔT = 30 °C - 10 °C = 20 °C
Step 3: Calculate the heat required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 4.184 J/g.°C × 5 g × 20 °C = 418 J
Name the functional Group in
CH₃CO₂H
Answer:
•Name the Functional Group in CH₃CO₂H
CH₃COOH ( acetic acid)→ Carboxylic acid (-COOH group)
The term “periodic” helps identify _______ that occur in the table, like electronegativity or atomic radii.
A. Atomic mass
B. Families
C. Patterns
If u can answer this thank you so much
Answer: ITS C OR B I THINK BUT I HAVE A FEELING ITS ONE OF THOSE
Explanation:
IM SO SORRY IF ITS WRONG KSDBDZDH
Answer:
C. Patterns
Explanation:
I got it right on usatestprep
2. A girl on a bike is accelerating at a rate of 5 m/s2 and has a total mass of 60 kg. How much force is the girl applying to her bike to move at this rate? *
Answer:
300N................
Explanation:
F=ma
m=60
a=5
A compound with molecular formula C4H8O2, shows absorptions at 2500-3300 cm-1 (broad), 1720 cm-1 and at 1200 cm-1 on the IR spectrum. Propose possible structure(s) for this compound.
Answer:
Butanoic Acid:
I have attached the structure of Butanoic Acid. Please refer to the attachment.
Explanation:
Solution:
First of all, we need to calculate the double bond equivalent (DBE) for the compound given:
Compound = C4H8O2
DBE = (C +1) - (H + X - N)/2
C = no. of carbons
H = no. of Hydrogen
X = no. of Halogens
N = no. of Nitrogen
DBE = (4+1) - (8/2)
DBE = 5-4
DBE = 1
It indicates the presence of 1 double bond in the possible structure.
Further structure can be identified by looking the peak values of the spectrum. So, we have,
2500 - 3300 = it indicates the presence of -COOH group
1720 = it indicates the (C=0) stretching
1200 = It indicates the (C-O) stretching
SO, the possible structure is
Butanoic Acid:
I have attached the structure of Butanoic Acid. Please refer to the attachment.
Suggest why people used to believe that water was an element.
It is right? or is it ice and acid at the samee timeee?
what process is the foundation of almost all food webs
Answer:
The Sun is the major source of energy for organisms and the ecosystems of which they are a part. Producers such as plants, algae, and cyanobacteria use the energy from sunlight to make organic matter from carbon dioxide and water. This establishes the beginning of energy flow through almost all food webs
In another experiment, a 0.150 M BF4^-(aq) solution is prepared by dissolving NaBF4(s) in distilled water. The BF4^-(aq) ions in the solution slowly react with H2O(l) in the reversible reaction represented below.
BF4-(aq) +H20(l) → BF3OH-(aq) + HF(aq)
[HF] reaches a constant value of 0.0174 M when the reaction reaches equilibrium. For the forward reaction, the rate law is rate = kf [BF4-]. The value of the rate constant kf was experimentally determined to be 9.00x10-4 min-1.
Required:
a. Calculate the rate of the forward reaction after 600 minutes.
b. A student claims that the initial rate of the reverse reaction is equal to zero. Do you agree or disagree with this claim?
Answer:
A) Forward rate = 1.1934 × 10^(-4) M/min
B) I disagree with the claim
Explanation:
A) We are told that [HF] reaches a constant value of 0.0174 M at equilibrium.
The reversible reaction given to us is;
BF4-(aq) +H20(l) → BF3OH-(aq) + HF(aq)
From this, we can see that the stoichiometric ratio is 1:1:1:1
Thus, concentration of [BF4-] is now;
[BF4-] = 0.150 - 0.0174
[BF4-] = 0.1326 M
From the rate law, we are told the forward rate is kf [BF4-].
We are given Kf = 9.00 × 10^(-4) /min
Thus;
Forward rate = 9.00 × 10^(-4) /min × (0.1326M)
Forward rate = 1.1934 × 10^(-4) M/min
(B) The student claims that the initial rate of the reverse reaction is equal to zero can't be true because at equilibrium, rates for the forward and reverse reactions are usually equal.
Thus, I disagree with the claim.
Each hydrogen atom has one valence electron, but it needs two electrons to be stable. How can both hydrogen atoms each achieve a stable configuration
Answer:Through Covalent Bonding
Explanation:
Both Hydrogen can achieve a stable configuration with 2 electrons by each sharing their electrons.
The name of this bonding is called covalent bonding. In this type of bonding, each participating entity (in this case, the hydrogen atoms) donates their valence electrons (the one valence electron in the hydrogen atoms) then share the total electrons (1 + 1 = 2).
MULTIPLE CHOICE QUESTION
Popcorn popping in a pot on the stove
is an example of:
1.The Kelvin scale
2.radiation
3.conduction
4.convection
Will give Brainiest answer
Answer:
Confection
Explanation:
Answer:
2 - Radiation
Explanation:
The air above the stove is heated and because it is gas, moves upward. This is convection. The bottom of the pot and the surface of the stove are not 100% flat. In those areas where the stove and the bottom of the pot are not in contact, radiation transports heat from the stove to the heat. Which heats up the kernals.
Consider five solutions that all have the same mass of solute in 100.0 mL of solution. Which has the highest concentration as measured in molarity
Answer:
d
Explanation:
a. KCl
b. NaCl
c. Na2SO4
d. NaF
e. CaCl2
The molarity of a solution is a measure of the number of moles of solutes per volume (in liters) of the solution.
The number of moles of a solute depends largely on the mass and the molar mass of the solute. Hence,
mole = mass/molar mass
Equal amounts of KCl, NaCl, Na2SO4, NaF, and CaCl2 would have a different number of moles due to a difference in their molar mass. The higher the molar mass, the lower the number of moles, and vice versa.
The molar mass (in g/mole) of each of the solute compounds is as follows
KCl - 74.55
NaCl - 58.44
Na2SO4 - 142.04
NaF - 41.99
CaCl2 - 110.98
NaF has the lowest molar mass and, hence, would have the highest number of moles. This means that when an equal amount of the substances above is dissolved in the same amount of water, NaF would have the highest molarity.
The correct option is d.
What would happen if a plant was unable to receive pollen? A.the plant would continue to produce fruits and seeds. B.the plant would be unable to produce fruits and seeds.
C.Instead of the pistil producing pollen, the ovule would produce it.
D.Instead of the stamen producing pollen, the stigma would produce it.
Answer:
I think its B only because nothing else makes sense
Explanation:
but you should take your best guess
To solve this we must be knowing each and every concept related to plant. Therefore, if a plant was unable to receive pollen then the plant would be unable to produce fruits and seeds. The correct option is option B.
What is plant?Plants are mostly photosynthetic eukaryotes in the Plantae kingdom. Traditionally, the plant kingdom comprised all non-animal living creatures, including algae and fungi; but, all current definitions include Plantae exclude fungi and certain algae, as well as prokaryotes.
According to one definition, plants belong to the group Viridiplantae (Latin for "green plants"), which is sister to the Glaucophyta and includes green algae as well as Embryophyta (land plants). If a plant was unable to receive pollen then the plant would be unable to produce fruits and seeds.
Therefore, if a plant was unable to receive pollen then the plant would be unable to produce fruits and seeds. The correct option is option B.
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Which of the following is a characteristic science?
Answer:
what are the answer choices?
Explanation:
Answer:
The Answer is A
Explanation:
It asks questions about the natural world.
Hope this helps!!
