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.
A single atom of an element has 21 neutrons, 20 electrons, and 20 protons, which elementis it?
Answer:
Calcium
Explanation:
The number of protons is the atomic number of the element. Number 20 on the periodic table is Calcium.
An ion with 11 protons 12 neutrons and a charge of + 1 has an atomic number of
what? And how many electrons total?
Answer:
11 electrons total and 23amu
Explanation:
This tells us that sodium has 11 protons and because it is neutral it has 11 electrons. The mass number of an element tells us the number of protons AND neutrons in an atom (the two particles that have a measurable mass). Sodium has a mass number of 23amu.
What does eggshells change color under the influence of various liquids?
Answer:Adding calcium to chicken's food is going to make the eggshells firmer. Independent variable:
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.
What must happen for an electron to become excited?
An electron must absorb light energy
An electron must release light energy
If you leave your home at noon, and the speed limit is 50 km/h on the highway, what is the approximate time will you get to Atlantic City if Atlantic City is 150 km away? (obeying the speed limit of course)
Answer:
The time you will get to Atlantic City is 3 pm
Explanation:
Given;
speed limit, v = 50 km/h
distance to be traveled, d = 150km
The time of the motion is given as;
time = distance / speed
t = (150 km) / (50 km/h)
t = 3 hours
Thus, if you leave your home at noon, the time you will get to Atlantic City is given as;
time to get home = 12 pm + 3hours = 3 pm
Therefore, the time you will get to Atlantic City is 3 pm
PLEASEEE HELP FAST!!!! PLEASEEE!!!!!!!
What type of radioactive decay is represented by the arrow?
Alpha
Beta
Gamma
Answer:
beta
Explanation:
Which sample contains the same number of atoms as a gram-atomic mass of He?
1.
6 g of C
2.
7 g of Li
3.
8 g of o
4.
9 g of F
Submit Answer
Answer: 2. 7g of Li
Explanation: A mole of any substance contains the same number of particles (Avogadro's number, 6.02*10^23). 1 gram atomic mass of He (4g) is equivalent to 1 mole; so is 1 gram atomic mass (7g) of Li
Which organisms are typical decomposers?
Answer:
Insects, bacteria and fungi
Explanation:
A 30 gram ball is at rest. Next, a force pushes the ball to the north for 2.5 seconds and the ball accelerates for a rate of 0,70 m/s/s. How fast is the ball going after the 2.5 seconds of acceleration? For credit, who work in detail
Answer:
1.75m/s or 6.3km/hr
Explanation:
here,
acceleration (a) = 0.7m/s^2
mass (m) = 30g
time (t) = 2.5s
initial velocity (u) = 0m/s
final velocity (v) = ?
now,
v = u + at
or, v = 0 + 0.7 * 2.5
hence, Final velocity (v) = 1.75 m/s
if u want to convert to km/hr
then,
1.75 * 3.6 (we know that 1m/s = 3.6km/hr)
= 6.3km/hr
During photosynthesis what takes place under the leaf
Answer:
In plants, the process of photosynthesis takes place in the mesophyll of the leaves, inside the chloroplasts. Chloroplasts contain disc-shaped structures called thylakoids, which contain the pigment chlorophyll.
Explanation: Hope this helps
What are some ways that scientists use to model chemical reactions?
Answer:
they identify factors that affect chemical processes then they determine the amount of substance produced or consumed then predict the amount of energy released or absorbed
The potential difference between the top and bottom of a D cell battery is
Answer:
Does it have a picture?
Explanation:
The potential difference between the top and bottom of a D cell battery is derived by the use of a voltmeter between the +ve and -ve poles.
What is the Potential difference?The potential difference is simply defined as two points that reflect the energy released in transferring a unit quantity of electricity from one spot to the other.
In conclusion, Potential difference is also known as the voltage across two points in a circuit.
Read more about Voltage
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Which of the following redox conditions will produce a spontaneous reaction?
A. The sum of the voltages of the half-reactions is positive.
O B. The sum of the voltages of the half-reactions is negative.
O C. The voltage of the reduction half-reaction is positive.
D. The voltage of the reduction half-reaction is negative.
Answer:
A. The sum of the voltages of the half-reactions is positive.
Explanation:
correct on a p e x
Among the following redox conditions those will produce a spontaneous reaction is The sum of the voltages of the half-reactions is positive.
What are redox reactions?Redox reactions are the reactions in which reduction reaction and oxidation reaction happens simultaneously. The term ‘redox’ is a short form of reduction-oxidation. All the redox reactions can be broken down into two different processes: a reduction process and an oxidation process.
The loss of electrons and the corresponding increase in the oxidation state of a given reactant is called oxidation. The gain of electrons and the corresponding decrease in the oxidation state of a reactant is called reduction.
For example-
H₂ + F₂ → 2HF
Hydrogen is added to Fluorine gas so Fluorine has been reduced but Hydrogen has been oxidised.
Therefore, Among the following redox conditions those will produce a spontaneous reaction is The sum of the voltages of the half-reactions is positive.
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Select True or False.
The Sun is like the stars we see at night.
False
True
Answer:
yes
Explanation:
Sun is a star not a planet.
Yes true I guess but its just a lot closer
Get me the answers please
Answer:
a is a opinon answer
Explanation:
Answer:
a. opinion
Explanation:
Considering 2N2H4(g) + N2O4(g) -> 3N2(g) +4H2O(g)
How many grams of N2H4 will be needed to produce 121.3g of H2O
Answer:
107.8
Explanation:
64 gram of N2H4 produce 72 gram of H20
then by crossmultiplication
64*121.3/72=107.82
How many moles of sodium hydroxide are required to react completely with 23.1 moles of sulfuric acid?
H2SO4(aq) + NaOH(aq) = 2H2O(L) + Na2SO4(aq)
Select one:
a. 46.2 moles NaOH
b. 11.6 moles NaOH
c. 5.78 moles NaOH
d. 23.1 moles NaOH
Answer:
46.2 moles of NaOH are required.
Explanation:
Given data:
Moles of NaOH required = ?
Moles of H₂SO₄ = 23.1 mol
Solution:
Chemical equation:
H₂SO₄ + 2NaOH → 2H₂O + Na₂SO₄
Now we will compare the moles of NaOH with H₂SO₄.
H₂SO₄ : NaOH
1 : 2
23.1 : 2×23.1 = 46.2
Thus, 46.2 moles of NaOH are required.
A can of cola contains approximately 240 calories. If you consume two cans of cola each day for one week, approximately how many calories did you consume from cola?
Select one:
a. 3,400 calories
b. 70 calories
c. 1,700 calories
d. 480 calories
Why cells are called "little giants"?
Answer:
Giant cell, also called Langhans giant cell, large cell characterized by an arc of nuclei toward the outer membrane. The cell is formed by the fusion of epithelioid cells, which are derived from immune cells called macrophages. Once fused, these cells share the same cytoplasm, and their nuclei become arranged in an arc near the outer edge of the cell. Langhans giant cells typically form at the centre of granulomas (aggregates of macrophages) and are found in the tubercle, or primary focus of infection, in tuberculosis, in lesions of syphilis, leprosy, and sarcoidosis, and in fungal infections.Large cells that form by fusion in reaction to the presence in the body of foreign substances differ from Langhans giant cells in that their many nuclei are scattered throughout the cell. In giant-cell tumours of bone and tendon the cells have many nuclei crowded together. The megakaryocytes, the normal bone-marrow cells thought to be the source of the blood platelets, are also called giant cells.
Explanation:
I'M WORKING ON THIS SUBJECT TOO!!!!!
How do the different cycles of energy and matter on Earth interact with each other?
Answer:
Energy enters the biosphere as sunlight. Plants change this energy into chemical energy through the process of photosynthesis. Then, the energy is passed to organisms that eat the plants. Energy and matter are also passed between organisms when they eat one another.
pls give me brianliest and rate me
how many moles of barium hydroxide would be required to react with 117 g hydrogen bromide?
PLEASE HELP !!
Use the diagram below to answer the following questions.
PLEASE HELP
E TE
Figure B
In Figure B, which region contains the noble gas family of elements?
ОА
OD
ОС
OB
Noble gas located in the region D
Further explanationNoble gas are located in group 18 in the periodic table consisting of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), have a stable electron configuration where the valence electrons are 8(full outer shell of electrons), so it is very hard to react because of its stability
If we look at the periodic system of the elements, the noble gases are on the far right, so that in Figure 8 it is located in area D
And the other region :
A : alkali elements(group 1),
B : alkaline earth elements(group 2)
C : halogen elements(group 17)
At what rate does magma deep below Earth's surface cool? What size of crystal results from magma cooling deep below Earth's surface?
O A. Slowly, large crystals form
B Quickly, large crystals form
C. Slowly, small crystals form
D. Quickly, small crystals form
Answer:
i think it is A
Explanation:
i got this answer from a good friend
The magma deep below Earth's surface cool slowly.Large crystals form results from magma cooling deep below Earth's surface. Therefore, option A is correct.
What is magma ?Magma is the molten or semi-molten natural material that gives rise to all igneous rocks. Magma can be found beneath the Earth's surface, and evidence of magmatism has been discovered on other terrestrial planets and natural satellites.
When magma slowly cools deep within the crust, the resulting rock is known as intrusive or plutonic. Because of the slow cooling, crystals can grow large, giving intrusive igneous rock a coarse-grained or phaneritic texture. Individual crystals in phaneritic texture can be seen with the eye.
Intrusive igneous rocks form when magma slowly cools and solidifies beneath the Earth's surface. Large, well-formed crystals are found in intrusive igneous rocks such as granite, gabbro, diorite, and dunite.
Thus, option A is correct.
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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:
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"
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:
The only nonmetal in Group 14 is
A carbon.
B. oxygen.
C. nitrogen.
D. fluorine.
Answer:
carbon
Explanation:
i just googled it
teapot filled with water is heated on the stove. What does the heat from the stove do to the molecule of water in the teapot?
Answer:
The kettle on the stove takes thermal energy from the stove and uses it to convert water into steam at constant temperature. The molecules of water vibrate with increasing speeds when the temperature of water increases. When the temperature of water reaches the boiling point, water starts to change its state to steam.
Explanation:
two differences between atom and molecules
Answer:
Molecules are made of atoms. atoms are smaller. molecules have no electrons, atoms do.
Answer:
well one of the begins with and A while the other one begins with a M, joking so the difference between an atom and a molecules is that, An atom is the smallest unit of matter that retains all of the chemical properties of an element. while Molecules can be described as the smallest particle of an element or a compound, which is capable to exist independently and shows all the properties of the respective substance. Hope this helps :)
Explanation: