Answer:
288 grams
Explanation:
The amount of any radiative substance left after some time is calculated by
amount left = [tex]x/2^n[/tex]
where x is the initial amount of substance
n is the number of half lives
one half live is the time in which amount of substance reduce to half of its initial value.
------------------------------------------------------
amount left = 4.5 grams
half life of iodine-125 = 60 days
total time in which substance reduced to 4.5 grams = 360 days
thus,
number of half life in 60 days = 360/60 = 6
thus, there are period of 6 half lives
in each half life the amount of substance reduces to its previous half
let the initial amount be x grams
using the formula
amount left = [tex]x/2^n[/tex]
[tex]4.5 = x/2^6 \\ 4.5 = x/64\\x = 4.5*64 = 288[/tex]
Thus, 288 grams was the initial amount of iodine-125
what two elements make up the most of the earth's core
Answer:
The Earth's core is mainly made of iron and nickel.
Explanation:
Answer: The Earth's core is mainly made of iron and nickel.
Explanation:
A 57.9 gram mass has a volume of 3 cm 3. What is the density of the mass?
Answer:
The answer is 19.3 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume}\\[/tex]
From the question
mass = 57.9 g
volume = 3 cm³
We have
[tex]density = \frac{57.9}{3} \\ [/tex]
We have the final answer as
19.3 g/cm³Hope this helps you
When hit from behind in a car crash, a passenger can suffer a
neck injury of whiplash. This is an example of Newton's
law,
Answer:
Neck injury, and back injury
Which best describes the data?
Answer:
The average?
Explanation:
When measuring the volume of a liquid, why is it best to use a measuring container that is narrow?
Answer:
n the sciences, the “tools” for measuring the volumes of liquids are generally made from glass, plastic or occasionally metal, although professionals referred to all of them as “glassware.” Scientists, and chemists in particular, have a variety of glassware at their disposal for measuring volumes. The particular piece of glassware chosen in any situation will depend primarily upon two factors: the required volume and the accuracy required for the measurement.
Explanation:
Hope this helps leave a heart c:
what frequency does television channel 7 broadcast at?
Answer:
Channel 7's frequency is 117.5 MHz
Answer:
174 MHz - 180 MHz w/ center frequency of 177 MHz
Explanation:
216 - 174 = 42
42/7 = 6
6 + 174 = 180 - 7 - 177 MHz
180 + 6 = 186 - 8 - 183 MHz
186 + 6 = 192 - 9 - 189 MHz
192 + 6 = 198 - 10 - 195 MHz
198 + 6 = 204 - 11 - 201 MHz
204 + 6 = 210 - 12 - 207 MHz
210 + 6 = 216 - 13 - 213 MHz
If 96.5 grams of gold has a volume of 5 cm, what is the density of gold?
Which argument is correct about the growth of an organism?
Only genetic factors affect the growth of an organism.
Only genetic factors affect the growth of an organism.
Only environmental factors affect the growth of an organism.
Only environmental factors affect the growth of an organism.
The combination of genes and environmental factors affects the growth of an organism.
The combination of genes and environmental factors affects the growth of an organism.
Genes remove the environmental factors that affect the growth of an organism.
Genes remove the environmental factors that affect the growth of an organism.
Answer: The combination of genes and environmental factors affects the growth of an organism.
Explanation:
Gene consists of DNA and it's heredity physical and functional unit. Genes play a vital role in a organisms growth. For example in humans, if one's parents are tall, there's a large tendency that such child will be tall and vice versa.
Environmental temperature also affects growth of living organisms. These include water soil pH, temperature, gender, chemicals etc. These all affects growth, it should be noted that proteins in living organisms can be damaged at a certain temperature which invariably affects the growth of such organism.
Also, the environment influences gene expressions as temperature, light, drugs, and chemicals, affects genes as they determine which ones will either be turned on or off which will further lead to how such organism grows.
What is the purpose of this material in the nucleus?*
O
makes antibodies
DNA makes protein molecules to help with almost every cellular process.
о
DNA makes super molecules to help with almost every cellular process.
to make concrete
Answer: DNA makes protein molecules to help with almost every cellular process.
i think?
What is the primary type of heat transfer?: A cool breeze blows off the water.
Answer:
Explanation:
Heat transfer occurs by three main mechanisms: conduction, where rigorously vibrating molecules transfer their energy to other molecules with lower energy; convection, in which the bulk movement of a fluid causes currents and eddies that promote mixing and the distribution of thermal energy
5) How do you describe a person who likes
inventing stories?
Plz Help ;_; :v
Answer:
One word for this is, raconteur - it means a person skilled in telling anecdotes. anecdotist. narrator, or storyteller
Explanation:
Forensic psychiatry focuses on the relationship between human behavior and criminal justice.
O True
O False
A bucket is filled with pebbles and water. How can the contents of the bucket be classified?
A. A compound
B. A heterogeneous mixture
C. A solution
D. A homogeneous mixture
How would you record the length of an object?
Answer:
a ruler
Explanation:
Which particle matters the most when it comes to stable atom protons or neutrons?
Answer:
Protons
Explanation:
Protons are worth 1, while neutrons are neutral and are worth zero.
The density of a gas is 0.68 g/mL. What amount of space would 23.8 g of this gas occupy
5. How many elements do we have in Octane?
5 elements
2 elements
20 elements
26 elements
Answer:
2 elements
Explanation:
Octane is composed of carbon and hydrogen atoms.
what type of compound is iron (3) oxide
Answer:
B Group Salt (Ionic Bond)
Explanation:
Iron (III) Oxide
Fe2O3
Answer:
Carbon Trioxide
Explanation:
Pesticides are a type of wastewater
pollutant.
True
False
Calculate the wavelength of a photon of light having a frequency of 3.50 x 1015 Hz. A. 1.05 x 1024 m B. 1.33 x 1016 m C. 8.57 x 10-8m D. 1.17 x 107 m
Answer:
1.17x107m
Explanation:
A mass spectrometer has determined the mass and abundances of all isotopes of an unknown element. The first isotope has a mass of 38.96amu (93.28%) and the second a mass of 40.96amu (6.72%). Calculate the average atomic mass and identify the unknown element, WRITE ONLY THE SYMBOL FOR YOUR ANSWER.
Answer:
I believe it is Potassium (K)
Explanation:
I did the math on a calculator and it was the closest atomic mass to potassium.
Except for helium, all the elements in the last column of the periodic table have
valence electrons.
0 7
0 8
О О
O 18
Answer:
O
Explanation:
they have O valence electrons
Water is a pure substance. Which of the following is true about water?
a
A chemical change is required to separate the elements present in it.
b
A physical change is required to separate the elements present in it.
c
It is made up of two compounds, each with a different set of atoms.
d
It is made up of an element and a compound.
Answer:
A chemical change is required to separate the elements present in it.
Explanation:
The only true statement from the choices given is that water as a pure substance requires a chemical change to separate the elements present in it.
Water is a molecule consist of two atoms of hydrogen and one atom of oxygen.
The atoms are covalently bonded together. A chemical process, the electrolysis of water is often used to separate the atoms of a water. Physical changes cannot be used to separate the atoms of water. Water is a compound which consists of two elements.Therefore, we see that only the first choice satisfies this problem.
How many elements are in the following equation? salt pure water(NaC/
+ H2O)
Answer:
4
Explanation:
Sodium Na, Carbon C, hydrogen H2, Oxygen O
The amount of gravitational force between objects depends on their...
O Masses and the distance between them
O Masses and the frictional forces between them
O Speed and direction of motion
O Speed and the distance between the masses
Answer:
mass and distance between them
Compounds are different than elements because compounds are–
Group of answer choices
a pure substance; elements are not.
not able to be broken down into parts.
made from the same type of atoms.
combinations of two or more elements.
Answer: Compound are different than elements because compounds are combinations of 2 or more elements.
what will happen to the speed of sound if you sing your favorite song during a cold day?
Answer:
The speed will decreaseHow many atoms are in 1.9 g C? Answer in units of atoms.
Answer:
9.5E22
Explanation:
(1.9/12.011)×6.02E23
The atomic mass of Gallium is 69.72 AMU. The masses of the naturally occurring isotopes are 68.9257 AMU and 70.908 AMU for Ga-69 and Ga-71. Find the percent (%) abundance for each.
Answer:
40.7% abundance of Ga-71
59.93% abundance of Ga-69
Explanation:
Given data:
Average atomic mass of Ga = 69.72 amu
Atomic mass of Ga-69 = 68.9257 amu
Atomic mass of Ga-71 = 70.908 amu
Percent abundance of each isotope = ?
Solution;
we know there are two naturally occurring isotopes of Ga.
First of all we will set the fraction for both isotopes
X for the isotopes having mass 68.9257
1-x for isotopes having mass 70.908
we will use the following equation,
68.9257x + 70.908 (1-x) = 69.72
68.9257x +70.908 - 70.908x = 69.72
68.9257x - 70.908x = 69.72 - 70.908
-1.9823x = - 1.188
x= 1.188/1.9823
x= 0.5993
0.5993 × 100 = 59.93 %
59.93 % is abundance of Ga-69 because we solve the fraction x.
now we will calculate the abundance of Ga-71.
(1-x)
1 - 0.5993 = 0.4007
0.4007× 100= 40.7 %
40.7 % for Ga-71.
what is the volume when the density is 7.83g/ml and 19.6 grams?