Homework #1 Problem Set
DECAY KINETICS, EQUILIBRIUM, DATING
tor
the less
1. If 140Ba is freshly separated from a fission product mixture and found to contain 125
milliCi, (a) what is the activity of 14°La that will grow into the sample in 17.2 hr? (b)
What is the maximum activity of 140La that will ever be present in the sample, and (c)
when will it occur?
a. A=
Ti
T₂-T2
x Ap * (e-Azt – e-dzt)
A=
12.75 d
12.75 d -1.678
x 125 mCi x (e 306 h*17.2 h
In2
In2
e 40.272 h
x
17.2 ") = 31.38 mCi
b. A=
12.75 d
12.75 d-1.678
Inz
x 125 mCix (e 12.75 d*
x 5.65 d
In2
e 1.679 d
a *5.65 d) = 91.3 mci
c. tm = 1.4427 x
12.75 x 1.678 12.75
X In
12.75-1.678 1.678
= 5.65 days
the wa
2
A short-lived radioisotone

Answers

Answer 1
i don’t understand all of this copy and paste..

Related Questions

What do we call living things that share characteristics including processes that make life possible?

Question 3 options:

chemical properties


structure


organisms


energy

Answers

Answer:
Organisms

Step-by-step explanation:

Properties of Life. All living organisms share several key characteristics or functions: order, sensitivity or response to the environment, reproduction, growth and development, regulation, homeostasis, and energy processing.

Electron-dot diagrams Show all the electrons in an element?

Answers

An electron dot diagram shows an atom's number of valence electrons

Answer:

flase

Explanation:

i got the answer from khan


How many moles of water are produced from 0.500 moles of oxygen gas?

Answers

As far as I know NONE.....
Explanation:
Sodium peroxide can be thermolyzed to give dioxygen gas...
N
a
2
O
2
(
s
)
+
Δ

N
a
2
O
(
s
)
+
1
2
O
2
(
g
)





But with water, we simply get an acid base reaction....
N
a
2
O
2
(
s
)
+
2
H
2
O
(
l
)

2
N
a
O
H
(
a
q
)
+
H
2
O
2
(
a
q
)
...

In determining the density of a rectangular metal bar, a student made the following measurements length 8 53 cm, width, 24 cm, height 10 cm, mass, 527064 g Calculate the
density of the metal to the correct number of significant figures​

Answers

Answer:

d = 2.57456 g/cm³

Explanation:

Given data:

Length of metal bar = 853cm

Width = 24 cm

Height = 10 cm

Mass = 527064 g

Density of metal = ?

Solution:

Volume of metal bar:

Volume = length × width × height

Volume = 853 cm × 24 cm × 10 cm

Volume = 204720 cm³

Density:

d = m/v

d = 527064 g / 204720 cm³

d = 2.57456 g/cm³

Which solution conducts electricity?
O Salt Solution
O Sugar Solution
O Both
O Neither

Answers

Answer - salt solution
Explanation- This is because salt in an ionic compound and can easily move electrons between positive and negative ions.

What is the concentration of a solution with a volume of 2.5 liters containing 600 grams of calcium phosphate?​

Answers

Answer:

1.12M

Explanation:

Given parameters:

Volume of solution  = 2.5L

Mass of Calcium phosphate  = 600g

Unknown:

Concentration  = ?

Solution:

Concentration is the number of moles of solute in a particular solution.

Now, we find the number of moles of the calcium phosphate from the given mass;

        Formula of calcium phosphate  = Ca₃PO₄

         molar mass = 3(40) + 31 + 4(16) = 215g/mol  

Number of moles of  Ca₃PO₄  = [tex]\frac{600}{215}[/tex]   = 2.79moles

   Now;

  Concentration  = [tex]\frac{Number of moles }{volume }[/tex]  

 Concentration  = [tex]\frac{2.79}{2.5}[/tex]   = 1.12M

How many moles of Oxygen (O) are in 20.15x10^25 atoms of O?

Answers

Answer: 334.6 moles of O, 167.3 moles as O2

Explanation:

20.15x10^25/6.02214076x10^23 = 334.6 as atoms, 167.3 as O2

A Lewis structure is a two-dimensional representation of a molecule that does not necessarily show what shape that molecule would take in three dimensions. Based on the Lewis structure and your knowledge of VSEPR theory, approximate the smallest bond angle in this molecule.
..
x--------y--------x
..

Answers

Answer: The smallest bond angle in the molecule x-y-x is [tex]180^0[/tex]

Explanation:

According to VSEPR theory , each atom in a molecule will achieve a geometry that minimizes the repulsion between electrons in the valence shell of that atom.

In the given compound [tex]x-y-x[/tex], the number of electron pairs is 2 that means the hybridization will be [tex]sp^2[/tex]  and geometry of the molecule will be linear as there are two bond pairs .The bond angle for linear geometry is 180° which reduces the electron electron repulsions and maximise stability.

Question 4 of 5
In the suburbs, per capita consumption of fossil fuels is very high. What is the
most likely effect of this?
A. A decrease in nitrates in the soil
B. An increase in carbon dioxide in the atmosphere
O
C. An increase in phosphates in groundwater
D. An increase in oxygen in the air
SUBMIT

Answers

Answer:

B

Explanation:

Answer:

B. An increase in carbon dioxide in the atmosphere

Explanation:

4.Which sentence BEST describes the relationship between the plates in Earth's crust and the sizes of the landmasses on top of the plates?

A.The plates and the landmasses are approximately the same sizes.

B.The plates are much smaller than the size of the landmasses.

C.The plates are much larger than the size of the landmasses.

D. The plates are different in size from the landmasses.

Answers

Answer:

D. The plates are different in size from the landmasses.

Explanation:

The tectonic plates that are also called lithospheric plates are very massive and irregular-shaped rocks that are composed of both the continental and the oceanic lithosphere and they may vary from a few hundred to thousands of square km.

Based upon the context clues of the lesson, what do you think will be the relationship between Charles and his parents
O it will be deceitful and confusing
It will be apathetic and non-caring
It will be wonderful and loving
o it will be full of anger and fighting

Answers

Answer:

It is the first or second one. The other two didn't work for me.

Explanation:

Hope this helps :)

Answer:

It will be apathetic and non-caring

Explanation:

hi

Which is NOT something an organism must do to survive?


Question 2 options:


obtain energy to live



communicate verbally



maintain structure



produce offspring

Answers

Answer:

communicate verbally and maintain structure

Communicate verbally

how is geologic activity & geologic structure similar?

Answers

Explanation:

Geological activity determines geological structures. The prevalent types and forms of tectonic working in a place will control the form of structure that can be found in a terrain.

In volcanic region, it is common to see volcanic structures of different types such as calderas, strato-volcano etc. These structures are formed by the volcanic activities. Also, in a karst topography, we find sink holes, stalactites and stalagmites etc. due to the nature of the geologic activities going on. Some sedimentary rocks shows cross bedding due to the environment where they form.

So, geologic activities controls the structure found in an area

Where do all of the elements heavier than Hydrogen come from?
A. They were always there.
B. They were forged inside of stars.
C. They were formed during the Big Bang.
D. They developed on Earth when it formed.

Answers

B.They were forged inside of stars.

How many moles are equal to 157.8g of CaCl2?​

Answers

Answer:

Explanation:

K: 157.8 g CaCl2

U: ? mol CaCl2

1Ca = 1(40.08) = 40.08

2 Cl = 2(35.45) =+70.90

110.98

157.8 g CaCl2 1 mol CaCl2

x

1 mol CaCl2 110.98 g CaCl2


HELP HELP HELP

how are scientist using computer models to simulate worldwide ocean activity

Answers

Answer:

An ocean current is a continuous, directed movement of seawater generated by forces acting upon this mean flow, such as breaking waves, wind, the Coriolis effect, cabbeling, and temperature and salinity differences. Features like depth contours, shoreline configurations, and interactions with other currents also influence an ocean current’s direction and strength. Ocean currents flow for great distances, and together, create the global conveyor belt that plays a dominant role in determining the climate of many of the Earth’s regions (illustrated in the NASA video below). For example, the Gulf Stream makes northwest Europe much more temperate than any other region at the same latitude. Another example is Lima, Peru where the climate is cooler than the tropical latitudes in which the area is located, due to the effect of the Humboldt Current.  Ocean modelling uses a mathematical model of the general circulation of an ocean, based on the Navier–Stokes equations on a rotating sphere with thermodynamic terms for various energy sources (radiation, latent heat). These equations are the basis for complex computer programs commonly used for simulating the atmosphere or ocean of the Earth.

Explanation:

Blue green and red are _____ colors of light ?

Answers

Answer: the

Explanation:

How many molecules are there in 968 grams of H2SO4?

Answers

there are 5.7997 molecules

Answer:

5.7997

Explanation:

Explain what would happen to the air temperature at Riverdale School over the course of the
day if the groundwater system were used. Use the terms stability and change in your
explanation (2 pts).

Answers

Answer:

In each Amplify Science unit, students figure out

a phenomenon by asking questions, gathering

evidence, and coming up with an explanation of how

the phenomenon works. The Coherence Flowchart

visually represents the storyline of the unit, showing

the coherent flow of questions, evidence, and ideas that

support students as they build complex explanations

of the unit’s anchor phenomenon. The Coherence

Flowchart on the following pages (one chapter per

page) can be used to see the connections between

the questions that drive students’ experiences, the

evidence they gather, the ideas they figure out, and the

new questions that those ideas generate. The diagram

to the right explains the structure of a chapter in the

Explanation:

в
D
5. At which point is the sonar travel time going to be the shortest?

Answers

Answer:

okay ☺️

b. it's b

Explanation:

b

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