Answer:
2.5 g mass of Ra-226 will remain after 4800 years.
Explanation:
Given data:
Mass of Ra-226 = 20 g
Sample remain after 4800 years = ?
Solution:
Half life of Ra-226 = 1600 years
Number of half lives passed = T elapsed / half life
Number of half lives passed = 4800 year / 1600 year
Number of half lives passed = 3
At time zero = 20 g
At first half life = 20 g/2 = 10 g
At 2nd half life = 10 g/2 = 5 g
At 3rd half life = 5 g/2 = 2.5 g
Thus, 2.5 g mass of Ra-226 will remain after 4800 years.
1. Suppose that there were two isotopes of Sodium.
28% of the naturally occurring sodium atoms had a
mass of 22, and 72% atoms had a mass of 23. What
would the average atomic weight of sodium be?
Answer: C. The university surveys 600 randomly selected students who attend the university. Correct
Explanation:
22.72 is the average atomic weight of sodium.
What are isotopes?Isotopes are different versions of a specific element.
1st isotopes of 22u = 28%
2nd isotopes of 23u = 72%
The average atomic weight of sodium be=
22 x 28 + 23 x72
=2272/100
=22.72
Hence, 22.72 is the average atomic weight of sodium.
Learn more about isotopes here:
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Ublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water
Answer:
True
Explanation:
Sublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage.
For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water which bypasses the conversion to liquid stage and goes straight to the gaseous form.
I have no idea how to do this help plz!
Please Answer ASAP!!
What happens to the velocity of an object when balanced forces act on it?
a.
There will be no change
c.
There will be negative acceleration
b.
There will be positive acceleration
d.
Velocity will change, but not acceleration
Please select the best answer from the choices provided
Answer:
C. There is a negative acceleration
Explanation:
I majored in Physics
what happens when exhaled air passes through clear lime water?
please help !!!!!!!!!!!
Answer:
Iron wood is very dense and will sink in water. B
Explanation:
Hope this helps!!
Answer:
B
Explanation:
In a living cell which process uses up atp
Answer:
Metabolism
Explanation:
because energy change takes place
The Earth's _____ provides protection from meteorite impacts by causing them to _____.
please leave a simple answer
Answer:
atmosphere, break up
Explanation:
Answer:
Atmosphere, break up
Explanation:
please help ASAP it is maybe easy for you!!!
Answer:
the answer is C, 30g
what causes a change in air pressure
what types of organisms are most likely to become extinct (characteristics)?
What does the little ‘3’ in 2NH3 mean?
Answer:
It determines the number of molecules
Answer:
it means there are 3 hydrogen atoms in the compound.
Which statement is true about a reaction represented by a chemical equation that shows energy as a reactant?

A.
It absorbs energy.

B.
It releases energy.

C.
It is a replacement reaction.

D.
It is a combustion reaction.
Which one has the greatest mass, Hg or Co?
Answer:
Hg
Explanation: I just took the test
Why is it important to pasteurize certain liquids?
Answer:
Pasteurization involves heating liquids at high temperatures for short amounts of time. Pasteurization kills harmful microbes in milk without affecting the taste or nutritional value (sterilization= all bacteria are destroyed).
Explanation:
A gymnast performing a backflip into a cartwheel on a balance beam is am example of ________ force
A small windmill is to be built at a science competition. A large floor fan is used to power each windmill The task
is to lift a bucket filled with the most number of pennies possible from a height of one meter in one minute.
Which change in decision would most likely increase the weight that the windmill could lift?
A)
Make the fan blades smaller.
B)
Make the arms of the windmill longer,
C)
Make the arms of the windmill shorter
D)
Make the fan blades out of a lighter material.
Answer:
D
Explanation:
I'm doing USA test prep and I got it right
Answer:
Explanation:
It is D
Make the fan blades out of a lighter material.
ill attach a picture
Answer:
35.50
Explanation:
There are two stable isotopes, 35Cl (75.77%) and 37Cl (24.23%), giving chlorine a standard atomic weight of 35.45
25cm3 of a 0.4M sodium hydroxide solution was diluted into 250cm3 of water. What is the molarityof the resultant solution.
Answer:
0.04 M
Explanation:
From the question given above, the following data were obtained:
Initial volume of solution (V1) = 25 cm³
Initial Molarity of solution (M1) = 0.4 M
Final volume of solution (V2) = 250 cm³
Final Molarity of solution (M2) =?
We can obtain the final Molarity of the solution by using the dilution formula as illustrated below:
M1V1 = M2V2
0.4 × 25 = M2 × 250
10 = M2 × 250
Divide both side by 250
M2 = 10/250
M2 = 0.04 M
Therefore, the resulting molarity of the diluted solution is 0.04 M
I need help with chemistry question?
Answer:
2Al + 3Na2SO4 -----> Al2(SO4)3 + 6 Na
Explanation:
Product should be Al2(SO4)3
Because Al contains +3 charge
And SO4 contains -2 charge
To balance this postive and negative charge we multiple +3 with 2 and -2 with 3
What chemical process occurs in cells to release energy?
A.
Oxidation
B.
Respiration
C.
Pespiration
D.
Nutrition
Answer:
B. Respiration
Explanation:
cellular respiration is the process where cells use glucose (C6H12O6) and oxygen gas (O2) to make carbon dioxide (CO2) water (H2O) and ATP, which is energy
formula:
C6H12O6 + 6O2 -> 6CO2 + 6H20 + 38ATP
The sum of the atomic masses of all the atoms in a compound is called the
Could you use filtration on a solution?
Answer:
No.
Explanation:
This is because a solution is a mixture with two substances that have already dissolved in each other and so there is no residue left. Filtration works such that part of the mixture has smaller particles that can pass through the membrane of the filter paper while the bigger particles get stuck onto the paper as residue. A solution has a uniform size particle throughout and thus filtration does not work for purifying a solution.
How does dermal tissue play a key role in transpiration?
Answer:
Dermal tissue of the stems and leaves is covered by a waxy cuticle that prevents evaporative water loss. Stomata are specialized pores that allow gas exchange through holes in the cuticle. Unlike the stem and leaves, the root epidermis is not covered by a waxy cuticle which would prevent absorption of water.
Explanation:
what did bohr consider electrons as?
A. Discrete particles
B. Continuous particles
C. Particles with zero energy
D. None of the above
Answer:
D?
Explanation:
I think D hmm is the answer if I am wrong pls anyone or someone type the right answer but for me is d
Answer:
NOT D!!!!
Explanation:
I am taking the quiz on ck12, it is NOT "none of the above"
1. Se preparan 750 ml de una disolución en agua, que contiene 0,00071 moles de Nitrato de potasio para adobar una carne de res. Calcular la ppm de la disolución. 2. Una muestra de 600 ml de disolución tiene 4 mg de ión fluoruro (F-). Cuántas ppm de F hay en la muestra?. Ayudaaaaaa plis
Answer:
1. 95.7 ppm
2. 6.67 ppm
Explanation:
Podemos pensar la denominación ppm como partes por millón, es un tipo de unidad que define concentración de solutos en una solución.
ppm = μg/g o si lo queremos ver en volumen, μg/mL
Quiere decir microgramos de soluto en 1 g de solución o mL de solución.
Ej 1. En primer lugar convertimos los moles de KNO₃ a gramos
0.00071 mol . 101.1 g/mol = 0.071781 g
Si pasamos los gramos a μg → 0.071781 g . 1000000 μg/ 1g = 71781 μg
Dividimos 71781 μg /750 ml = 95.7 ppm
Ej 2. Convertimos los mg a μg → 4 mg . 1000 μg/ 1 mg = 4000 μg
Ahora dividimos: 4000 μg /600 ml = 6.67 ppm
guys help please. A rigid container holds a gas at a pressure of 55 kPa and a temperature of -100.0°C. What will the pressure be when the temperature is increased to 200.0°C?
Answer:
It’s 150 C :)
Explanation:
A green pea plant (Gg) is crossed with a yellow pea plant (gg). What is the probability that the offspring will be heterozygous?
A.25%
B.50%
C.75%
D.100%
Answer:
50 percent
Explanation:
G g
g Gg gg
g Gg gg
since one of the plants are already heterozygous, only half will be heterozygous since the other plant is homzygous
There is 50% probability that the offspring will be heterozygous.
What is heterozygous?At a given gene locus, the existence of two different alleles. One normal allele and one mutant allele, or two separate mutated alleles, can make up a heterozygous genotype (compound heterozygote).
what is allele?An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome.
so, if green pea plant (Gg) is crossed with a yellow pea plant (gg), there will be 50% probability that the offspring will be heterozygous, we can find it by making punnett square so here is the solution
Hence, the correct option is B i.e. 50%
To know more about heterozygous here
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An atom of hydrogen loses its electron. What is its charge
Answer:
When an atom of hydrogen loses its electron it becomes positively charged.
Hope it will help you........Final Answer: +1
Explanation/Reasoning:
Because hydrogen is an atom (not an ion), you'll write it as H (not H+). Hydrogen (H) has one proton and one electron, so if it loses its electron, it will only have one proton. Therefore, it becomes an ion of H+. This means that the charge will be +1.
~I hope I helped you :)~
what method would you use for your hypothesis.