How much radium-226 will remain from a 20 gram sample after 4800 years?
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.
Please select the word from the list that best fits the definition
Measured in grams of solute per gram of solution
concentration
solubility
Answer:
Solubility
Explanation:
Solubility units that incorporate units of solution include grams of solute per 100 grams of solution or grams of solute per liter of solution. Another way to express solubility is in moles of solute per liter of solution; this ratio is called "molarity."
1. Solve for x
Atomic number 31
Atomic mass x
Number of protons y
Number of neutrons 33
Number of electrons 28
Charge of element z
Answer:
Atomic mass = proton + neutron
31+33= 64
Number of proton = Atomic number = 31
Charge of element is +3
Explanation:
write the metals and nonmetals and metalloids in the first 30 elements
Answer: Metals: Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn
Non-metals: H, He, C, N, O, F, Ne, Si, P, S, Cl, Ar
Metalloid: B
Explanation: The first 30 elements are H, He, Li, Be, B, C, N, O, F, Ne, Na,
Mg, Al, Si, P, S, Cl, Ar, K, Ca, Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn
Metallic elements are more electropositive (tending to form ions by donating electrons) with fewer electrons in their outer shell
Non-metallic elements are more electronegative (tending to form ions by accepting electrons) with more electrons in their outer shell
Metalloids are elements somewhere between, but without any specific clear boundary between them and metals/non-metals
group1 and group2 elements, with one or two outer electrons, are all metals: Li, Na, K, Be, Mg, Ca
similarly the transition metals 21-30 are all electropositive and metals.
The noble gases He, Ne, Ar are gases that have completed outer shells and are non-metallic, likewise the halogens F, Cl with 7 outer electrons, and O and S with 6 are non-metals. N and P (5 outer electrons) are non-metallic as are C and Si (4 outer electrons).
This leaves H, B, Al. H, with its single electron close to the nucleus is a non- metallic gas. Al (3 outer electrons) is metallic, but B, has its 3 electrons close to the nucleus and has the in-between character of a metalloid.
Is the sodium Nitrate solution acidic, basic , neutral? and why ?
Answer: Sodium Nitrate solution is neutral.
Explanation: Sodium nitrate solution has strong bases and strong acids so it would have a neutral pH of 7.
Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes. What does this represent about the type of change happening in the container?
Complete Question:
Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes. What does this represent about the type of change happening in the container?
Group of answer choices
A. A chemical change started immediately and finished at eight minutes.
B. A non-chemical change started immediately and finished at eight minutes.
C. A chemical change occurred at four minutes.
D. A non-chemical change occurred at four minutes.
Answer:
A. A chemical change started immediately and finished at eight minutes.
Explanation:
A chemical reaction can be defined as the chemical process which typically involves the reaction between two or more chemical elements (substances) to form a new compound, through the rearrangement of the ionic or molecular structure of each chemical element.
This ultimately implies that, a chemical reaction is a chemical change that immediately starts when two or more molecules of a chemical element (substance) known as reactants are combined together to form a new product (compound).
In this scenario, Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes. Thus, what this represent about the type of change happening in the container is that, a chemical change (from red to blue) started immediately and finished at eight minutes.
Agl + Na25 yields Ag2S + Nal
Explanation:
Agl+hih+356bnh$&56DG hug zero cg hydh hod sir un bucks
How many grams of calcium are made up by 2.68 x 1023 atoms?
Answer:
Mass = 17.8 g
Explanation:
Given data:
Number of atoms of Ca = 2.68 × 10²³
Mass in gram = ?
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
2.68 × 10²³ atoms × 1 mole /6.022 × 10²³ atoms
0.445 mol
Mass in gram;
Mass = number of moles × molar mass
Mass = 0.445 mol × 40 g/mol
Mass = 17.8 g
Each organ system has specific functions for the body's survival. Which body system is responsible for carrying oxygen from the lungs to the body cells and transporting glucose for energy?
Group of answer choices
Answer:
Circulatory System
Explanation:
Blood carries oxygen to the rest of the body, as well as glucose.
What is the relationship between the number of digits and the evolution of the tetrapod?
Answer:As the tetrapod evolved, the number of digits decreased
Explanation:
Answer: During the evolution of the tetrapod limb, the number and pattern of elements along the proximal–distal axis (running from the shoulder to the fingers) has remained invariant, while the number and pattern of elements along the autopod anterior–posterior axis (thumb to little finger, also designated digi
Explanation:
An allotrope of carbon that is structured in a sphere is called:
A. fullerene
B. tetrahedron
C. graphite
D. diamond
Answer:
fullerene
Explanation:
Convert 76.8 cm to m.
Answer:
0.768 m
Explanation:
1 cm = 0.01 m
76.8 cm * 0.01 m/ 1 cm
0.768 m
Margarita set up three vials on a hot plate. She poured the same amount of
liquid into each of the vials, and then she turned on the hot plate. Which event
could be a significant source of error in her experiment?
Answer: Since the vials are filled the same, and are placed on the same hot pad, all the water will evaporate at the same time
Explanation:
The source of error in the experiment is the vials being filled the same, and placed on the same hot pad, all the water evaporating at the same time .
What are errors?Errors in chemical analysis result when there is a difference between observed value and the true value.If the magnitude of errors is large , it results in decrease in accuracy, reproducibility, and precision.
There are three types of errors:1) random error 2) systematic error 3) human error.The cause of random errors are difficult to quantify while the human errors can be minimized by taking a range of readings to reduce the error.
Errors while measuring boiling point may be human errors while noting down the boiling temperature or instrumental or systematic error if there is a fault in the thermometer.
Learn more about error,here:
https://brainly.com/question/15810279
#SPJ7
why sodium and chlorine are active element
A 20 N object is placed on a surface and starts to slide. What is the MOST likely reason the object begins to move?
A O Gravity exerts a balanced force on the object.
В.
Friction is applied to the object.
c. An unbalanced force causes acceleration.
D
The forces acting on the object are in equilibrium.
Answer:
c.
Explanation:
If the object starts to slide it must be on a slope.
There are 2 forces acting on the object - gravity and the friction between the object and the surface.
If sliding starts then the forces must be unbalanced.
The force of gravity is greater than the friction.
Answer:c
Explanation:
7. Base your answer to the following question on the information below and on your knowledge of biology A student designed an experiment to investigate a claim that athletes would have lower heart rates than nonathletes during exercise. After the students classified themselves as an athlete or a nonathlete, their resting pulses were determined. Then all the students performed the same exercise for four minutes and their heart rates were determined by recording the pulse rate in beats per minute. The students continued to measure their pulse rates for an additional four minutes. The average heart rate per minute for each group was determined. The data were recorded, as shown on the table below Average Heart Rate Response to Exercise (beats per minute) Time (minutes) Athlete Students Nonathlete Students Resting Pulse 68 72 1 76 78 2 82 90 Exercising Period 3 115 95 110 4 130 5 100 125 6 95 120 After Exercise 7 85 100 8 68 95 2.4 To improve the validity of the conclusion reached in this experiment, the students should repeat the experiment A) disregarding any data that don't fit the hypothesis B) with a larger number of athletes and nonathletes C) comparing the heart rates and breathing rates of males and females D) with the athletes doing different exercises than the nonathletes
fountain
21. Calculate the quantity of electricity
in coulombs used when a current of
2.7 ampere is passed through a
solution of silver salt for 25 minutes
20 seconds
A. 87.5
B. 206
C. 1350
D. 4050
E. 4104
Answer:
4104 Coulombs
Explanation:
charge = time(sec) *current
25*60 =1500+20=1520
2.7A * 1520 sec =4104
4104 C
Why does the rate of dissolution for a gas decrease as the temperature of a solvent increases?
more space for the solute to escape
less space for the solute molecules
less space between solvent molecules
more collisions between solute and solvent molecules
Answer:
As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return back to the gas phase. As a result, the solubility of a gas decreases as the temperature increases.
Explanation:
22.
An example of amphoteric oxide is
A. Al2O3.
B. CaO.
C. Cuo.
D. SiO2.
E. K20.
Fu** please help
Answer:
A (option) .............
Answer:
Al2O3
Explanation:
ZnO,Al2O3,PbO2 are some of the amphoteric oxides
Amphoteric oxides are metal oxides that can react with both acids and bases,so Aluminum oxide can react with both HCl and Sodium hydroxide which is a base
Do you think it would be a good idea for a bumper car ride to have minimum and maximum weight requirements for riders? Apply Newton's second and third laws of motion in your response.
Answer: If only max or min yes but if we have min and max that is a bad idea it is not as safe.
helpppp:)))))))))ahhhh
Answer:
Calcium
Explanation:
what is the molar mass of nickel (ll) chloride(NiCl2)
Answer:
Explanation:
yt
Answer:
129.5994 g/mol
Explanation:
The oxidation # (charge) of an element called "lindenium "Ld is + 1 and the oxidation # (charge) of an element called "mendezine symbol "Mz, is -2. What is the chemical formula for the compound called lindenium mendezide?
Answer:
Ld₂Mz
General Formulas and Concepts:
Chemistry - Compounds
Valence shellsWriting chemical compoundsBalancing chargesExplanation:
Step 1: Define
"Lindenium" Ld w/ oxidation charge of +1
"Mendezine" Mz w/ oxidation charge of -2
Step 2: Write Compound
To balance out the charges to be neutral (0), we must counter balance the amount of Ld's with Mz's. We need 2 Ld's with 1 Mz to create a compound with a neutral charge:
2Ld¹⁺ + Mz²⁻
2(+1) + (-2) = (+2) + (-2) = 0 (neutral charge)
Therefore, our compound must be Ld₂Mz.
2CuO+2NH3------ 3Cu + 3H2O+ N2. Given that the relative molecular mass of copper oxide is 80, what volume of ammonia is required to completely reduce 120 g of Copper oxide? ( Cu=64, O=16, N=14)
Volume of Ammonia(NH₃) = 22.4 L
Further explanationGiven
Reaction
3CuO+2NH₃⇒ 3Cu + 3H₂O+ N₂
In the problem, the CuO coefficient should be 3 not 2
M CuO = 80
mass CuO = 120 g
Required
The volume of NH₃
Solution
mol CuO :
[tex]\tt mol=\dfrac{mass}{M}\\\\mol=\frac{120}{80}\\\\mol=1.5[/tex]
From the equation, mol ratio CuO : NH₃ = 3 : 2, so mol NH₃=
[tex]\tt \dfrac{2}{3}\times 1.5=1~mol[/tex]
Assume at STP(0 °C, 1 atm) ⇒1 mol = 22.4 L, then volume of NH₃=22.4 L
Displacement can be added to get the total
a) velocity
b) distance
c) speed
d) acceleration
3. Calculate the number of moles and mass in
gram_of_1 x 10^20mdecules of Nz gas
.
Answer:
0.17×10⁻³ mol
Mass = 0.00476 g
Explanation:
Given data:
Number of molecules of N₂ = 1 ×10²⁰ molecules
Number of moles of N₂ = ?
Mass in gram of N₂ = ?
Solution:
1 mole of any substance contain 6.022×10²³ molecules
1 ×10²⁰ molecules× 1 mol /6.022×10²³ molecules
0.17×10⁻³ mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 0.17×10⁻³ mol × 28 g/mol
Mass = 4.76×10⁻³ g
Mass = 0.00476 g
why is a frozen popsicle a homogeneous mixture and not a pure substance
Answer:
You can not see the sugar.
Explanation:
Which has a higher frequency: microwaves or blue light? How do you know?
Answer:
Microwaves
Explanation:
Microwaves have more energy than blue light
Among microwaves or blue light, blue light has a higher frequency. This is because blue light belongs to the visible region has a short wavelength and produces a higher amount of energy.
What is the relationship between frequency and wavelength?The frequency of any wave is inversely related to the wavelength. This means that when the frequency of the wave increases, the wavelength decreases. While the relationship between frequency is directly related to the energy.
According to the context of this question, gamma rays have the highest frequency and shorter wavelength, while radiowaves have a shorter frequency and the highest wavelength.
Therefore, blue light has a higher frequency. This is because blue light belongs to the visible region has a short wavelength and produces a higher amount of energy.
To learn more about the Frequency of waves, refer to the link:
https://brainly.com/question/16610625
#SPJ2
Which is the vector quantity that describes the shortest path between two points?
The shortest distance taken by the object to reach the destination at a minimum time is called acceleration. Thus value acceleration depends upon the displacement and time.
a school bus drives 35 mph down the street and slows as it approaches the stop sign