Answer:
50 millions years
Explanation:
1 to 1/2 to 1/4 to 1/8 to 1/16
It takes 4 half lives to get to 1/16 of the original amount
200 million/4 = 50 millions years
The half-life of the radioactive waste is 50 million years.
To calculate the half-life of the radioactive waste, we use the formula below.
Formula:R/R' = [tex]2^{n/a}[/tex]............... Equation 1Where:
R = Original amount of the radioactive wasteR' = Remaining amount of the radioactive waste after decayn = Total timea = Half-life of the radioactive waste.Assuming: The original amount of the radioactive waste is y
From the question,
Given:
R = yR' = y/16n = 200 million years.Substitute these values into equation 1
y/(y/16) = [tex]2^{200/a}[/tex]16 = [tex]2^{200/a}[/tex]Solve for a
[tex]2^{200/a}[/tex] = 2⁴Equating the base
200/a = 44a = 200a = 200/4a = 50 million years.Hence, The half-life of the radioactive waste is 50 million years.
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2 C4H10+13 O2 = 8 CO2+10 H2O
identify the above chemical reaction type.
how many moles of water are produced when 43 grams of oxygen gas are reacted.
Answer:
This chemical reaction is a combustion.
n = 1.8mol
Explanation:
The ratio of oxygen to water is 13 to 10
The ratio of oxygen to water is also 43 grams to x
Cross multiply: 13x = 430 grams
Isolate x: x = 33.0769g
Remember that n = mass/Molar mass
The molar mass of water is 18.01528 g/mol
n = 33.0769/18.01528
n = 1.836048
Ioijihjghigyfhjjiiujhfcgj jjjdf
Answer:
this are the topics of biology so you have to learn this topics.
1) An enzyme is a secretion that helps the cell to perform its basic functions.
2) Activation energy is the minimum energy required for a cell to operate.
3) gastritis is an acid secreted by the stomach. it is a very strong acid
What metal is often extracted and purified from its ore using both smelting and electrolysis?
Answer:
Aluminium
Explanation:
The bauxite is purified to yield a white powder – aluminium oxide (also known as alumina) – from which aluminium can be extracted.
in a compressional wave, when the particles are far apart, what is the part known as
Answer:
The answer is: "Rarefactions"
Explanation:
In a longitudinal wave, particles of the medium vibrate in a direction that is parallel to the direction that the wave travels. Places where particles of a medium crowd closer together are called compressions, and places where the particles spread farther apart are called rarefactions.
How are force, mass, and velocity related in collisions?
Answer:
force=d/t, n
Mass=v/t
velocity=m/d
Why do metals tend to be good conductors of electric current?
A.Metals have more negative charges than positive charges, which produces electric currents.
B.The force of attraction between metal ions and electrons is very weak, causing electrons to flow out of the metal.
C.Valence electrons of metals are very mobile and can carry electric current through the metal.
D.Cations and anions in the metal easily move in opposite directions, carrying electric current
Answer:
C.Valence electrons of metals are very mobile and can carry electric current through the metal.
Explanation:
Metal is made or held together by metallic bonds. Basicaly the valence electrons are free to move through an intire body of metal.
Why do automobiles rust more easily in wet climates than drier climates.
Answer:
The iron rusts more easily in wet climates because there is more water in the air, this allows more oxygen to come in contact with the metal to rust.
Explanation:
in the spectrophotometric method, you were instructed to obtain the phosphate stock solution in a dry beaker. why is this? how would the slope of your calibration curve be affected if your beaker was not dry?
If wet beakers are used, a systematic error is introduced and the calibration curve for the determination will be inaccurate.
Spectrophotometry is a method of analysis that depends on the interaction of light with matter. Usually, the absorbance of light depends on the concentration of the sample.
In order to use the spectrophotometric method, a calibration curve is first prepared and used to determine the concentration of the unknown sample. A dry beaker should be used to avoid dilution of the standard solutions used for calibration. If they are diluted, a systematic error is introduced and the calibration curve for the determination will be inaccurate.
The slope of the of this experiment is a measure of sensitivity and a wet beaker will give the false impression of low sensitivity.
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a solution has a pH of 2. What best describes the solution?
a strong acid
a strong base
a neutral solution
a weak base
What volume (in mL) of 0.2600 M HBr is
required to neutralize 40.00 mL of 0.8000 M
NaOH?
The volume of 0.26 M HBr required to neutralize 40 mL of 0.8 M NaOH is 123.08 mL
We'll begin by writing the balanced equation for the reaction. This is given below:
HBr + NaOH —> NaBr + H₂O
From the balanced equation above,
The mole ratio of the acid, HBr (nA) = 1
The mole ratio of the base, NaOH (nB) = 1
From the question given above, the following data were:
Volume of base, NaOH (Vb) = 40 mL
Molarity of base, NaOH (Mb) = 0.8 M
Molarity of acid, HBr (Ma) = 0.26 M
Volume of acid, HBr (Va) =?The volume of the acid, HBr needed for the reaction can be obtained as follow:
MaVa / MbVb = nA / nB
0.26 × Va / (0.8 × 40) = 1
0.26 × Va / 32 = 1
Cross multiply
0.26 × Va = 32
Divide both side by 0.26
Va = 32 / 0.26
Va = 123.08 mLTherefore, the volume the acid, HBr needed to neutralize the base, NaOH is 123.08 mL
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For the reaction 2HNO3 + Mg(OH)2 → Mg(NO3) 2 + 2H2O, how many grams of magnesium nitrate are produced from 4 grams of nitric acid, HNO3 ?
Round your answer to the nearest tenth. Do not round your answers until the last step of the problem. If you do, the computer might mark your answer incorrect and you will be asked to complete your second trial for this assessment.
Use the following molar masses:
Element Molar Mass
Hydrogen 1
Magnesium 24
Nitrogen 14
Oxygen 16
Answer:
First check to make sure you have a balanced equation
Second use mole ratios to set up what you need to know
Finally convert the moles to grams using the correct molecular weight
I will get you started
According to the reaction above, one mole of Magnesium Nitrate is produced from 2 moles of Nitric Acid
1 mole of Mg(NO3)2/2 moles of HNO3
5 grams of Nitric acid contains
5 g * 1 mole/63 g of Nitric Acid = 0.079365079 moles
Explanation:
For the reaction 2HNO3 + Mg(OH)2 → Mg(NO3) 2 + 2H2O,0.0793grams of magnesium nitrate are produced from 4 grams of nitric acid, HNO3.
What is magnesium nitrate ?Magnesium nitrates are inorganic substances with the formula Mg(NO3)2x, where x is one of six, two, or zero. Each one is completely white. The hygroscopic anhydrous substance swiftly transforms into the hemihydrate when exposed to air. In both water and ethanol, all the salts are extremely soluble.
Magnesium nitrate is a crystalline (sand-like), flavourless, colourless, or white substance. Both the production of petrochemicals and pyrotechnics employ it as a catalyst.
The inorganic nitrate salt of magnesium is called magnesium nitrate. It functions as fertilizer. It is a magnesium salt and an inorganic nitrate salt.
Convert the moles to grams using the correct molecular weight
According to the reaction
one mole of Magnesium Nitrate is produced from 2 moles of Nitric Acid
1 mole of Mg ( NO3 ) 2 / 2 moles of HNO3
5 grams of Nitric acid contains
5 g * 1 mole/63 g of Nitric Acid
= 0.079365079 gram
Thus, For the reaction 2HNO3 + Mg(OH)2 → Mg(NO3) 2 + 2H2O,0.0793grams of magnesium nitrate are produced from 4 grams of nitric acid, HNO3.
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Observations are made by using one of the five senses (touch, sight, taste, smell, hearing) to gather information.
Kenneth sees the rock shown below.
Kenneth wants to write down an observation about the rock in his science notebook.
Which of the following is a scientific observation?
A.
The rock came from a cave.
B.
The rock is pretty.
C.
The rock is purple.
D.
The rock is very old.
answer B the rock is purple
Match each organism to its part in the food chain.
people:
deer:
horse:
snake:
goldfish:
grass:
lion:
bacteria:
Answer:
Explanation:
Grass. Producer
Goldfish. Pri. Consumer and Herbivores
Deer. Pri. Consumer and Herbivores
Horse. Pri. Consumer and Herbivores
Snake. Sec. Consumer and Carnivores
Lion. Tert. Consumer and
carnivores
People Pri. Sec. and tert. Consumers
Bacteria. Decomposers
How many CO2 molecules are in 1 mole of carbon dioxide?
I think there are 6.02 × 10power23 ( Avogadro's constant)
Why would A zoological veterinarian be a good job. DO NOT COPY AND PASTE. please do a paragraph why.
Answer:
it could be a good job because you will get the chance to explore how animals work not only that zoological veterinarian helps animals if they are in danger or needs help immediately. there are much more benefits for zoological veterinarian
Which of the following is an example of a ground in a building?
A. A metal rod in the air
B. A pipe to the ground
C. An extra electrical cord
D. A plastic rod
I'll give brainliest to whoever gives the correct answer :D
Answer:
The answer is B
Explanation:
A pipe to the ground
HELP FASTTTTT WILL GIVE BRAINLIEST
The enthalpy of formation of C2H5OH is -238.7 kJ/mol. What information does this reveal about the bonds in the molecule?
a. Bond formation in C2H5OH from its elements only occurs in cold temperatures.
b. Bond formation in C2H5OH from its elements releases energy.
c. Bond formation in C2H5OH from its elements does not occur.
d. Bond formation in C2H5OH from its elements absorbs energy.
2C + 3H2 + 1/2 O2 --> C2H5OH dH = -238.7 kJ/mol.
hope it helpsWhat is the coefficient for iodide ions (I-) when the equation is balanced?
Answer:
When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be __6__.
Explanation:
From the redox equation, we can see that NO₃⁻ is reduced to NO (from oxidation state +5 to +2), whereas I⁻ is oxidized to I₂ (from oxidation state -1 to 0). The half reactions are balanced with H⁺ (acidic solution), as follows:
Reduction : 2 x (NO₃⁻(aq) + 3 e- + 4 H⁺ → NO(g) + 2 H₂O)
Oxidation : 3 x (2 I⁻(aq) → I₂(s) + 2 e-)
----------------------------------------------------------------------
Total equation: 6 I⁻(aq) + 2 NO₃⁻(aq)+ 8 H⁺ → 3 I₂(s) + 2 NO(g) + 4 H₂O
That is the redox equation with the smallest whole number coefficients.
Accordin to this, the coefficient for the iodide ion (I⁻) is: 6.
The abiotic components of an
ecosystem are
B. the animals and plants.
A. not important.
D. invisible.
C. nonliving.
Answer:
C. nonliving.
Explanation:
16. Which is NOT true of an atom obeying the
octet rule?
A. obtains a full set of eight valence electrons
B. acquires the valence configuration of a noble gas
C. electron configuration is unusually stable
D. has an s'p valence configuration
E. will lose electrons
Lures
The statement that is not true in the list of options is that an atom that is obeying the octet rule will loose electrons. An atom that is obeying the octet rule will neither loose nor gain electrons.
According to the octet rule, an atom is stable when it has eight electrons in its outermost shell. We must note that stability of atoms is the driving force for all chemical reactions.
Hence, the statement that is not true in the list of options is that an atom that is obeying the octet rule will loose electrons.
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Calculate the frequency of 4.1 x 10^-19
What is the name of Sn3(PO4)4 under the Stock system of nomenclature?
Answer:
Tin (IV) Phosphate
Explanation:
"Stock nomenclature for inorganic compounds is a widely used system of chemical nomenclature developed by the German chemist Alfred Stock and first published in 1919. In the "Stock system", the oxidation states of some or all of the elements in a compound are indicated in parentheses by Roman numerals."
Which of the following is NOT a benefit of renewable energy? *
O generates power on smaller scale
O can decrease pollution
O combats climate change
Answer:
O generates power on a smaller scale
Explanation:
The other two options are benefits of renewable energy. You're looking for a con instead of a pro.
Please help!!
KOH + HBr → KBr + H2O
A student sets up a titration apparatus with 25 mL of potassium hydroxide in the flask. In three to five sentences, explain how the student can use a 0.1 M solution of hydrobromic acid to determine the concentration of potassium hydroxide in the reaction.
A known volume of 0.1 M solution of hydrobromic acid is reacted with 25 mL and the concentration of the potassium hydroxide is calculated from the stoichiometry of the reaction.
Titration is a kind of reaction in which the concentration of an unknown solution is determined by reacting a known volume of this solution with a known volume of a standard solution and carrying out the necessary stoichiometric calculations in order to obtain the concentration of the unknown solution.
To obtain the concentration of the potassium hydroxide solution, 25mL of this solution is reacted with a carefully measured volume of the 0.1 M solution of hydrobromic acid. The volume of 0.1 M solution of hydrobromic acid required to reach end point is used calculate the concentration of the potassium hydroxide solution.
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The charge on an atom is written as a _____________.
Answer:
zero
Explanation:
For a single atom, the charge is the number of protons minus the number of electrons. Find the charge by balancing charge in a compound.
Ions can be made by single element or covalently bonded group of elements. The covalently bonded group of elements is called polyatomic ions or polyatomic atoms. Therefore, the charge on an atom is written as a superscript.
What is Ions?Any species that contain charge whether it is positive charge or negative charge is called ions. The example of polyatomic ions are sulfate, phosphate, nitrate etc.
Cation is the species that loose electron and attain positive charge while anion is a species which gain electron and attains negative charge so when anion and cation combine in fixed ration the the overall charge of the molecule is zero that is molecule is neutral, the charge over cation and anion is also called oxidation state. The charge on an atom is written as a superscript.
Therefore, the charge on an atom is written as a superscript.
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Science chemistry Question:
Are you doing a quiz?
A piece of sodium was cut easily into smaller pieces with a knife. The sodium was added to some water in a trough
The sodium:
.floated
.melated quickly to a silvery ball
.moved on the surface of the water
.fizzed
Answer:
Melated quickly into a silver ball
Answer:
C. melated quickly to a silvery ball
Explanation:
3. What makes water a polar covalent compound?
Answer:
Water is a polar covalent compound since it has Oxygen and Hydrogen which are 2 non-metals and the atoms have an unequal distribution of charge. Oxygen has δ- since it is more electronegative and Hydrogen has δ+. The shape of the water molecule is not symmetrical and dipoles are cancelled out making it a polar covalent compound.
Answer:
it is colourless
Explanation:
its tastleś
Someone pls help me :( tysm if u do
Density is mass/volume.
Let's find the volume.
Volume = lwh = (2)(2)(2) = 8
The volume is 8 and the mass is 16.
D = m/v
D = 16/8
D = 2
2 grams per cm^3
can somebody please help me with this question please
Answer: D
Explanation:
An object can store energy as the result of its position. For example, the heavy ball of a demolition machine is storing energy when it is held at an elevated position. This stored energy of position is referred to as potential energy. Similarly, a drawn bow is able to store energy as the result of its position. When assuming its usual position (i.e., when not drawn), there is no energy stored in the bow. Yet when its position is altered from its usual equilibrium position, the bow is able to store energy by virtue of its position. This stored energy of position is referred to as potential energy. Potential energy is the stored energy of position possessed by an object. https://taraenergy.com/blog/an-introduction-to-potential-energy/
