Given :
Half-life of Iodine , [tex]t_{0.5}=8 \ days[/tex] .
Initial concentration , [tex][A_o]=100\ mg[/tex] .
To Find :
The amount of sample remains after 32 days .
Solution :
Rate constant is given by :
[tex]k=\dfrac{0.693}{t_{0.5}}\\\\k=\dfrac{0.693}{8}\ s^{-1}\\\\k=0.086625\ s^{-1}[/tex]
Now , by rate law :
[tex][A]=[A_o]e^{-kt}[/tex]
Putting all given values, we get :
[tex][A]=100\times e^{-(0.086625)\times 32}\\[/tex]
[tex][A]=6.25\ mg[/tex]
Therefore , the remaining sample after 32 days is 6.25 mg .
Hence , this is the required solution .
An atom has a mass number of 19 and an atomic number of 9. What element is it? What is it’s symbol? How many protons, neutrons and electrons does it have? PLEASE HELP NEED ANSWER ASAP
Answer:
9 protons 9 electrons and 10 neutron
Explanation:
The atomic number is the number of protons .In a neutral atom,the number of electrons equals the number of protons.Mass number is the sum of the protons and nuetrons of a particular isotope.If you have mass number and atomic number,subtract the atomic number from the mass number to get the number of nuetrons. Mass number- atomic number= number of nuetrons
PLEASE HELP The arrows in the chart below represent phase transitions.
Three bars are shown labeled Solid, Liquid, and Gas. They are connected by arrows labeled 1 to 6. Arrow 1 points from liquid to gas; arrow 2 from solid to liquid, arrow 3 from solid to gas, arrow 4 from gas to liquid, arrow 5 from liquid to solid, and arrow 6 from gas to solid.
Which arrows represent the phase transitions in which heat energy is gained?
1, 2, and 3
2, 3, and 5
3, 4, and 5
4, 5, and 6
1, 2, and 3
hope it helps next time upload with picture
Round the the number below to the following places:
1254.6027
Rounded to the nearest... Correctly Rounded Number (Answer)
1000 place
100 place
10 place
1 place
10th place
100th place
1000th place
Answer: 1265.6037
Explanation:
What makes one atom different from another? The number of______in the_____
Answer:
protons in the nucleus
Carmen has a sample of matter. It is clear and smells sour. The sample is also thick but it flows when poured. Which is the best conclusion about Carmen's sample?
Answer:
liquid
Explanation:
In the given context, the sample as collected by Carmen is clear and the sample has a sour smell. It is also mentioned that the sample is thick sample and when the sample is poured on a surface it begins to flow.
Such a sample would be a liquid sample because anything that flows is a liquid. The liquid sample has a high viscosity since it is thick.
Answer:liquid
Explanation:
Because it flows
400 cm^3 =
L (Given: 1 cm^3 = 1 mL)
Answer:
1 cm^3 = 1 mL
Then
400 cm^3 = 400mL
Now convert mL to L
400/1000
0.4liter
How many moles ar Li are in 9.53x^24 atoms of Li?
Answer: 15.83 mol
Explanation:
To convert from atoms to moles, we will need to use Avogadro's number.
Avogardo's number: 6.022×10²³ atoms/mol
[tex]9.53*10^{24} atoms*\frac{1mol}{6.022*10^2^3 atoms} =15.83 mol[/tex]
Now, we know that there are 15.83 moles.
If a gas has a mass of 468 grams and its density is 17 grams per liter, how much volume does it occupy?
Answer:
The answer is
27.53 LitresExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{Density} [/tex]
From the question
mass = 468 g
Density = 17 g/L
Substitute the values into the above formula and solve
We have
[tex]volume = \frac{468}{17} \\ = 27.529411[/tex]
We have the final answer as
27.53 LHope this helps you
What do the elements Nickel and Technetium have in common?
Answer:
Both Nickel (Ni, 28, 58.69) and Technetium (Tc, 43, [98]) have these features in common:
transition metalssome gray color (Tc is silver)are in the d blockhave two electrons in valence shell (although Tc's valence is 6)very similar electronegativity levels (1.9 vs 1.91)don't have a refractive indexdon't have a critical temperaturedon't have a heat of combustion measurementdon't have an EU Number or NFPA hazard leveldon't have an autoignition point or a flashpointThere are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Therefore, nickel (Ni) and technetium (Tc) belongs to d block element.
What is periodic table?Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.
Periodic table help a scientist to know what are the different types of elements are present in periodic table so that they can discover the new elements that are not being discovered yet.
Both Nickel (Ni) and Technetium (Tc) have these features in common:
Both are transition metals that is belong to d block
Both have two electrons in valence shell
Electronegativity value of these elements are same
Therefore, nickel (Ni) and technetium (Tc) belongs to d block element.
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Did dalton’s atom have any protons, neutrons, and electrons?
Answer:
no
Explanation:
No, dalton’s atom haven't any protons, neutrons, and electrons because they were not discovered until later.
Answer:
No
Explanation:
no, because according to him an atom is a tiny indestructible sphere with mass on it. In his theory, Dolton did not know about Protons, neutrons and electrons.
Which statement provides background knowledge that helps a reader understand the theme of valuing all life found in"Birdfoot's Grampa"?
The journey is more important than the destination.
Toads can be poisonous and may attack when startled.
Grandparents and grandchildren often disagree.
It can be dangerous to stop a car on the side of the road.
Answer:D
Explanation:
Got it right
The statement which provides the theme of valuing all life found in the poem 'Birdfoot's Grampa' is the journey is more important than the destination.
What is the theme of Birdfoot's Grampa?The poem 'Birdfoot's Grampa' is written by the author Joseph Bruchac which narrates the story of an old man's journey to rescue the life of all toads that are seen on the road while he is driving during the night.
The poem gives us an idea that all life is important and is of value which we can understand through the immense tolerance and selflessness. The worth of our life is generally demonstrated in the poem.
Every ones life has a value whether it is small or big. This concern is shown in this poem through the character of Birdfoot's Grampa's continuous stopping of the car to rescue the toads which are seen on the road rather than just running them over.
Birdfoot's Grampa's is that much conscious and careful about the life of toads. All life is precious and the journey is more important than the destination is denoted in the poem.
Thus option A is correct - journey is more important than the destination.
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google takes its name from a conversion prefix. What is it and how big is it
Answer:
Giga, 1x10⁹.
Explanation:
Hello,
In this case, if we chew over Google's name, we can see that it suggests the word Giga which in conversion units context accounts for the Giga prefix (G) which has a value of 1x10⁹.
For instance 1 meter in gigameters is:
[tex]1m*\frac{1Gm}{1x10^9m}=1x10^{-9}Gm[/tex]
Which suggests that it is a huge unit and it makes sense considering the raft of information Google handles.
Regards.
I need help, pls someone help me!!
The density of manganese is 7.21 g/cm^3 . What is the density in kg/m^3 ? (dimensional analysis)
Answer:
7.21 x 103 kg/m3
Explanation:
Dimensional analysis has been the process to establish and convert the various units in the measurement. The density of manganese in kg/m3 is 7.21 × 10³ kg/m³.
What is dimensional analysis?Dimensional analysis has been the method that is also referred to as the unit factor or factor label method. It solves the mathematical expressions by multiplying the given value with another without changing its quantity and amount. It is used to change the units of the value.
Given,
Density of manganese = 7.21 g/cm³
The dimensional analysis method is used to convert grams per cubic centimeter into kilograms per cubic meter as:
1 gram / cubic centimeter = 1000 kilogram / cubic meter
So, 7.21 g/cm³ = X kilogram / cubic centimeter
Solving for X as:
X = 7.21 g/cm³ × 1000 kilogram / cubic centimeter
X = 7.21 × 10³ kg/m³
Therefore, 7.21 × 10³ kg/m³ is the density.
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what are 5 physical changes in matter
Answer:
cutting, bending, dissolving, freezing, and boiling
Explanation:
A physical change is a change in one or more physical properties of matter without any change in chemical properties. In other words, matter doesn't change into a different substance in a physical change. Examples of physical change include but are not limited to, from solid to liquid or from liquid to gas are also physical changes.
Which condition might develop if people eat contaminated raw or undercooked fish?
A. Cyclosporiasis
O B. Cryptosporidiosis
C. Giardiasis
O D. Anisakiasis
Density = mass/volume or Dam/v
calculate the density of a cube that measures 1.25 centimeter on a side
and has a mass of 43.0 grams.
Answer:
A brick of salt measuring 10.0 cm x 10.0 cm x 2.00 cm has a mass of 433 g. What is its density? Step 1: Calculate the volume. V = lwh = 10.0 ...
Missing: Dam/ 43.0
9. How many grams of zinc are needed to produce 12 grams of zinc chloride according to the following equation? Y-
Zn + Cl2 --> ZnCl2
12 grams of zinc
O 2.9 grams of zinc
O 11.6 grams of zinc
O 5.8 grams of zinc
Given :
A balanced chemical equation :
[tex]Zn +Cl_2->ZnCl_2[/tex]
To Find :
How many grams of zinc are needed to produce 12 grams of zinc chloride.
Solution :
Moles of [tex]ZnCl_2[/tex] ,
[tex]n=\dfrac{Given \ wt}{Molecular\ Mass}\\\\n =\dfrac{12}{136.30}\ mol\\\\n=0.088\ mol[/tex]
Now, by balanced chemical equation we can say that 1 mol of Zn produce
1 mol of [tex]ZnCl_2[/tex] .
So, 0.088 mol of Zn is required to produced 0.088 mol of [tex]ZnCl_2[/tex] .
[tex]Mass \ required = molecular \ mass \times moles\\\\m = 65.38 \times 0.088\\\\m=5.8 \ gm[/tex]
Therefore, 5.8 grams of zinc is required.
Hence, this is the required solution.
Which are different forms of an element that have different numbers of neutrons?
O ions
O isotopes
O compounds
O molecules
I need help pleaseeee
What is density????????????????
Answer:
Density is the mass per unit volume
Explanation:
Density is defined as mass divided by volume: where "p" is the density, "m" is the mass, and "V" is the volume.
Which of these is a physical property?
A) ability to burn a piece pf paper
B) pure sodium reacts violently with water
C) the boiling point of water is 100°C
D) helium does not tend to react with anything
Answer:
the boiling point of water is 100°C
Explanation:
I really need help with this before 5:10
Show your work
Your big brother has been brageing about how he can bench press 4.000 grams at the gym. Sounds impressive.
but you know better. Use your skills to find how many pounds of weight he is actually pressing.
( I got you fam. )
Answer ( assuming that your brother is doing 4,000 grams and not 4 grams ) :
around 8 pound's
Explanation:
1 gram = around 0.002 gram's
4,000 x 0.002 = 8
8 pound's :-)
Calculate the volume of a sample of iron that has a density of 6.8 g/mL and a mass of 6780 mg.
Answer:
m= 6780mg = 6.78g = 6.8g
d= 6.8g/ml
V= m/d
V= 1ml
Identify how many significant figures each number has. a. 297 b. 549 c. 4678 d. 327 e. 3006 f. 902 g. 8020 h. 0.0000053 1. 0.00002 j. 0.000506 k. 4000 1. 4000.0 m. 7.12 n. 3.05
Explanation:
a. 3 significant figures
b. 3
c. 4
d. 3
e. 4
f. 3
g. 3
h. 2
i. 1
j. 3
k. 1
l. 6
m. 3
n. 3
How many calories of heat are required to raise the temperature of 1.00kg of water from 10.2 degrees Celsius to 26.8 degrees Celsius?
Answer:
Explanation:
we know that specific heat is the amount of heat required to raise the temperature of substance by one degree mathmeticaly
Q=mcΔT
ΔT=T2-T1
ΔT=26.8-10.2=16.6
C for water is 4.184
therefore
Q=1.00*4.184*16.6
Q=69.4 j
now we have to covert joule into calorie
1 calorie =4.2 j
x calorie=69.4 j/2
so 69.4 j =34.7 calorie thats why 34.7 calorie heat is required to raise the temperature of water from 10.2 to 26.8 degree celsius
Describe, in terms of particle arrangement, why the substance with the smallest density and the substance with the largest density has different densities.
Explanation:
Density of a substance may be defined as the amount of mass or matter it contains in a unit space or volume of that substance. It is the quantity of the matter that a body possess or contains.
Mathematically,
density = mass / volume
Different substance shave different densities. The arrangement of molecules or atom particles in the substances makes a substance less denser or more denser than the other substance.
In liquid or gas, the molecules are loosely bound to each other and there are more empty space or void spaces in the substance. Thus this make liquid and gas less dense.
On the other hand, the molecules in solid are tightly bound and they are packed, with no or very less empty space. Therefore, solids have the largest density than the gases which have the smallest density.
Which of the following is the most accurate definition of a civilization?
humans being able to communicate with each other.
humans being able to travel to other regions
the stage of humans being able to find food
the stage of human social and cultural development
Answer:
The stage of human social and cultural development.
Explanation:
Answer:
The stage of human social and cultural development.
on:
A kilometer is much greater in distance then a millimeter true or false
Answer:
true
Explanation:
Answer:
true
because if you look at a chart it will lable
kilometercentimetermillimeterand so onNeed help with this question using dimensional analysis
Molding a shape from soft, malleable material (clay or plaster) or constructing a shape from harder material (such as metal or paper). Molding is what a child does with Play-Doh or origami.
Complete question is;
Molding a shape from soft, malleable material (clay or plaster) or constructing a shape from harder material (such as metal or paper) is called what?
Molding is what a child does with Play-Doh or origami
Answer:
Modeling
Explanation:
In chemistry, we have a branch called modeling chemistry. In modeling, we organize together a series of models instead of a collection of topics. In this approach, we will begin with a phenomena that can be readily observed and are gradually develop the simplest model of matter that helps us make sense of our observations.
Now in the question, we are Molding a shape from soft, malleable materials like clay/plaster or constructing from harder materials like metal/paper. This means that we are organizing a series of models from either soft & malleable or harder materials to produce a simple model shape.
Thus, this is simply modeling.