How much of a 100.0 gram sample of Gold-98 remains after 8.1 days if
its half-life= 2.7 days?
50.0 g
12.5 g
6.25 g
25.0 g
Answer:
If half-life is 2.7 days then 8.1 days is three half-lives. 12.5%, or 12.5g, of AU-198 would remain.
Explanation:
Helium only has two valence electrons and is a stable atom. How is this possible when atoms
need 8 valence electron to become stable?
Answer:
Explanation:
Helium (He) is similar in that it, too, only has room for two electrons in its only valence shell. Hydrogen and helium have only one electron shell. The first shell has only one s orbital and no p orbital, so it holds only two electrons. Therefore, these elements are most stable when they have two electrons.
what is the chemical formula for aluminium?
Answer
Aluminum is a silvery-white metal which is extremely soft by nature. Totally earth's crust contains 8% of Aluminum. Aluminium is a low-density nonmagnetic and ductile metal which can be made into sheets or wires as required
Explanation:
Answer:
Al
Explanation:
Aluminum is a silvery-white metal which is extremely soft by nature. Totally earth's crust contains 8% of Aluminum.
write a paragraph to explain how the transformation of water from one state of matter to another is important for the water cycle
In order for us to have water to drink, it first needs to go through a process called the water cycle. And in that water cycle there’s a process called evaporation. Evaporation is the process by which water changes from a liquid to a gas. In order for it to rain we need clouds and clouds are made of water. The water is heated causing water molecules to convert into gas, that gas then goes through a process called condensation creating clouds. At some point those clouds will be full of water, and all that water will then cause the cloud to release the water molecules causing rain.
The water cycle shows the continuous movement of water within the Earth and atmosphere. It is a complex system that includes many different processes.
Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow.There are four main parts to the water cycle:
Evaporation, Convection, Precipitation and Collection.
Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam.
The water vapor or steam leaves the river, lake or ocean and goes into the air.
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HELPPP ASAP 10 POINTSS
Which feature of a sound wave directly affects the pitch of the sound? (Pitch is whether it is sounds low like a rumble of thunder or high like a bird chirping)
Question 3 options:
frequency
wavelength
amplitude
longitude
Answer:
wavelength
Explanation:
what is Hydroelectricity?
Answer:
Hydroelectricity, or hydroelectric power, is electricity produced from hydropower. In 2015, hydropower generated 16.6% of the world's total electricity and 70% of all renewable electricity, and was expected to increase by about 3.1% each year for the next 25 years.
Explanation:
Answer:
The electricity which is produced from flowing water or from the force exerted by the flowing water is called Hydroelectricity..
hope it is helpful to you
Scientist introducing a gene to the DNA of these fish that cause the fish to glow an example of which application of biotechnology?
A. Artificial selection
B. Genetic Engineering
C. cloning
D. Artificial intelligence
Answer:
The correct answer is B
Explanation:
Genetic engineering is an example of which application of because the genes are changed to get the desired features in an organism.
What is genetic engineering?Genetic engineering is the process in which we alter the genetic makeup of an organism to produce desired characterictics in that organism.
So we can conclude that Genetic engineering is an example of which application of because the genes are changed to get the desired features in an organism.
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What is an example of Chemical energy to thermal energy to electrical current?
Answer:
Coal is burned at power plant.
Explanation:
the chemical Energy is released as coal changes
have a good day
Which shows an isomer of the molecule below?
Answer: C
Explanation:
Don’t trust the other person it’s not A
*view photo for answer*
pay attention! the answer choices aren't always in the same order!
In general, agitation causes the dissolving rate of most solutes to:
A- remain the same
B- increase
C- vary unpredictably
D-decrease
Which characteristics do stable ecosystems tend to have
Answer:
Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. Biotic factors include plants, animals, and other organisms. Abiotic factors include rocks, temperature, and humidity. Every factor in an ecosystem depends on every other factor, either directly or indirectly.
What causes day and night?
Make sure you give a full, detailed answer, not just one sentence.
Answer:
The earth's rotation, earth is rotating, so one side of earth will be hit by the sun, and the other wont be hit, making it dark, but since earth rotates, it causes it to turn, making one side have daylight, and the other, darkness, which the light you see is from the sun's reflection on the moon
Hope this helps
A dry, solid rock conducts electricity better than a long, meta wire.
True
False
Answer:
false
Explanation:
metal such as copper, silver, etc conducts heat and electricity. an object such as a rock, plastic, paper does NOT conduct heat.
Describe the law of conservation of mass in your own words *DO IT IN YOUR OWN WORDS PLEASE*
Answer:
Chemical reactions and physical transformations do not create or destroy mass in an isolated system, according to the law of conservation of mass. The mass of the products in a chemical reaction must equal the mass of the reactants, according to the conservation of mass law. The law of conservation of mass can be used to solve for unknown masses, such as how much gas is consumed or produced during a reaction.
M
Mass can be measured in local units like dharni pau eto. Discuss the advantages of using
standard units of mass over the local units of mass. (Any two points)
N2 Points)
soup answer
Answer:
1.They are reliable.
2.They dont vary from person to person
For Fe, its atomic number is 26 and its mass number is 56. How many neutrons does it have?
Answer:
the number of neutrons available is 30
Explanation:
Given that
The atomic number is 26
And, the mass number is 56
We need to determine the number of neutrons does it have
So, the number of neutrons is
= Mass number - atomic number
= 56 - 26
= 30
Hence, the number of neutrons available is 30
The same would be considered and relevant
The name for the process that causes fertile land to become dirt-like is??
Deforestation
Urbanization
Construction
Desertification
Answer:
Desertification?
Explanation:
Desertification is when fertile lands become desert like
2.14g of sodium sulfide react with excess hydrochloric acid to form sodium chloride and dihydrogen sulfide.
BALANCE IT TO AN EQUATION
Answer:
2.14 Na2S + 1.99 HCl ----> 3.20 NaCl + 0.935 H2S
Explanation:
The Balanced equation is
Na2S + 2HCl = 2NaCl + H2S
As we can see -
78.0452 g/mol of sodium sulfide reacts with 2 mole of HCl.
Mass of one mole of HCl = 36.458 g/mol
So, 78.0452 g/mol of sodium sulfide reacts with 2* 36.458 g/mol of HCL to produce 2* 58.44 g of NaCl and 34.1 g/mol of H2S
Thus,
2.14g of sodium sulfide will react with (2* 36.458/78.0452)* 2.14 of HCl
2.14g of sodium sulfide will react with 1.99 g of HCl
2.14 Na2S + 1.99 HCl ----> (2* 58.44/78.0452) *2.14 NaCl + (34.1/78.0452) * 2.14 H2S
2.14 Na2S + 1.99 HCl ----> 3.20 NaCl + 0.935 H2S
If a 750 mL of a gas at a pressure of 100.7 kPa has a decrease of pressure to 99.8 kPa, what is the new volume? Show work
Explanation:
P1V1 = P2V2
(100.7 kPa)(0.75 L) = (99.8 kPa)V2
V2 = (100.7 kPa)(0.75 L)/(99.8 kPa)
= 0.757 L
How many electrons are in an ion of calcium (Ca2+)?
A. 2
B. 18
C. 0
D. 22
How are the electron structures of carbon (C) and oxygen (O) similar? PLEASE HELP
Answer:
Carbon and oxygen are similar in a few ways. They are both elements, which are the fundamental building blocks of all matter. This means that they both have protons and electrons. They also both have neutrons
how do some plants grow and survive in the harshest environments like the dessert or under water
Answer:
Adaptation
Explanation:
Some plants grow and survive in the harshest environments like the desert or underwater by adapting to the environment. For example, some plants in the desert have thick, waxy skin to reduce loss of water and to reflect heat. They also have large, fleshy stems to store water. Also, specific plants like cacti in the desert have spikes to protect them from animals wishing to use stored water. These adaptations help them to grow and survive in the desert.
In the ocean, plants have adapted to absorb all the water and carbon dioxide they need from the water they live in. Just as cacti have adapted to live in brutally hot deserts, ocean plants have adapted to deal with things like ocean tides and the salinity (or salt levels) of the water around them. Many ocean plants cling tightly to rocks in order to avoid being swept away by ocean tides.
Hope this helps! Can I have brainliest?
this particle is an electron. it has no mass and has a negative one charge
gamma particle
alpha particle
beta particle
Answer:
The answer is a gamma particle.
Answer:
beta particle
Explanation:
8.45 cm - 3.55 cm = ?
Answer:
4.9cm or 4.90cm
Explanation:
Use column method and align the numbers. Make sure you add the decimal point before you write the answer, otherwise the value would be wrong.
Answer:
4.90
Explanation:
8.45.
-3.55
minus those two and you'll get the sum!
Iodine is prepared both in the laboratory and commercially by adding Cl2(g) to an aqueous solution containing sodium iodide. 2NaI(aq)+Cl2(g)⟶I2(s)+2NaCl(aq) How many grams of sodium iodide, NaI, must be used to produce 87.9 g of iodine, I2?
Answer:
[tex]m_{NaI}=104gNaI[/tex]
Explanation:
Hello there!
In this case, given the balanced chemical reaction, it is possible to evidence that the mole ratio of sodium iodide to iodine is 2:1 and the molar masses are 149.89 and 253.81 g/mol respectively; in such a way, we write the following stoichiometric setup in order to obtain the required grams of sodium iodide:
[tex]m_{NaI}=87.9gI_2*\frac{1molI_2}{253.81gI_2}*\frac{2molNaI}{1molI_2}*\frac{149.89gNaI}{1molNaI} \\\\m_{NaI}=104gNaI[/tex]
Regards!
What is the momentum of a motorcycle and a rider weighing 215 kg traveling at a speed of 62 meters per second?
Answer:
[tex]p=13330kg*\frac{m}{2}[/tex]
Explanation:
Hello there!
In this case, since the momentum of any body is calculated by multiplying the mass and the velocity:
[tex]p=m*v[/tex]
We simply need to multiply the 215 kg of the motorcycle by the velocity it has, 62 m/s to obtain:
[tex]p=215kg*62m/s\\\\p=13330kg*\frac{m}{2}[/tex]
Regards!
Describe the process used to dilute a stock solution?
Answer:
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Explanation:
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Which rule for assigning oxidation numbers is correct?
a.)Hydrogen is usually -1
b.)Oxygen is usually -2
c.)A pure group 1 element is +1
d.)A monatomic ion is 0
Answer:
Answer... Option B. Oxygen is usually -2; except in Peroxides
A chemist uses hot hydrogen gas to convert chromium(III) oxide to
pure chromium. How many grams of hydrogen are needed to
convert 76 grams of chromium(III) oxide, Cr203?
Answer: 3.024 g grams of hydrogen are needed to convert 76 grams of chromium(III) oxide, [tex]Cr_{2}O_{3}[/tex]
Explanation:
The reaction equation for given reaction is as follows.
[tex]Cr_{2}O_{3} + 3H_{2} \rightarrow 2Cr + 3H_{2}O[/tex]
Here, 1 mole of [tex]Cr_{2}O_{3}[/tex] reacts with 3 moles of [tex]H_{2}[/tex].
As mass of chromium (III) oxide is given as 76 g and molar mass of chromium (III) oxide [tex](Cr_{2}O_{3})[/tex] is 152 g/mol.
Number of moles is the mass of substance divided by its molar mass. So, moles of [tex]Cr_{2}O_{3}[/tex] is calculated as follows.
[tex]No. of moles = \frac{mass}{molar mass}\\= \frac{76 g}{152 g/mol}\\= 0.5 mol[/tex]
Now, moles of [tex]H_{2}[/tex].given by 0.5 mol of [tex]Cr_{2}O_{3}[/tex] is calculated as follows.
[tex]0.5 mol Cr_{2}O_{3} \times \frac{3 mol H_{2}}{1 mol Cr_{2}O_{3}}\\= 1.5 mol H_{2}[/tex]
As molar mass of [tex]H_{2}[/tex] is 2.016 g/mol. Therefore, mass of [tex]H_{2}[/tex] is calculated as follows.
[tex]No. of moles = \frac{mass}{molar mass}\\1.5 mol = \frac{mass}{2.016 g/mol}\\mass = 3.024 g[/tex]
Thus, we can conclude that 3.024 g grams of hydrogen are needed to convert 76 grams of chromium(III) oxide, [tex]Cr_{2}O_{3}[/tex].