Lead 214 emits then beta electrons to transform into bismuth 214 and polonium 214, which produces lead 210 through the emission of a third alpha particle. This series of transformations take place in a time span roughly equal to an hour.
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Which of the following is a savanna? a. Veldts b. Plains c. Steppes d. Llanos
Answer:
d) Llanos
Explanation:
Answer:
D . Llanos
Explanation:
A 4.00 (±0.01) mL Class A transfer pipet is used to transfer 4.00 mL of a 0.302 (±0.004) M Cu2+ stock solution to a 100.00 (±0.08) Class A volumetric flask. Deionized water is used to bring the flask to volume. Calculate the concentration of the diluted soluion in the volumetric flask and report its absolute uncertainty.
Answer:
concentration of diluted solution = 0.0125 ( ± 0.0002)M
Uncertainty = ± 0.0002
Explanation:
Given that
Initial volume of Cu2+ = 4.00 (±0.01) mL
Initial molarity 0f Cu2+ = 0.302 (±0.004) M
transferred to 100.00 (±0.08) Class A volumetric flask
first we get amount of water added
100.00 (±0.08) - 4.00 (±0.01) = 96 ± (0.09)
Now according to law of dilution
The concentration of Cu2+ after adding water
M1V1 = M2V2
we substitute
0.302 (±0.004) * 4.00 (±0.01) = x * 96 ± (0.09)
Now the multiplication of two digits with uncertainty is
(0.004/0.302) * 100 = 1.32% ; (0.01/4.00) * 100 = 0.25%
= [0.302 ( ± 1.32% )] * [ 4.00 ± (0.25%)]
= 1.208 ±(1.57%)
1.57/100 * 1.208 = 0.0189
so
= (1.208 ± 0.0189)
now substitute in our previous equation
1.208 ± (0.0189) = x * 96 ± (0.09)
x = 1.208 ± (0.0189) / 96 ± (0.09)
{ 0.09/96 * 100 = 0.094% }
so x = 1.208 ± (1.57%) / 96 ± (0.094% )
x = 0.0125 ± ( 1.664)
now( 1.664/100 * 0.0125)
= ± 0.000208
Hence
concentration of diluted solution = 0.0125 ( ± 0.0002)M
Uncertainty = ± 0.0002
How do the coefficients in a balanced equation compare quantities of two
substances?
O A. The ratio of the coefficients equals the ratio of the masses of the
substances
O B. The sum of the coefficients of the reactants equals the sum of the
products
O C. The ratio of the substances' coefficients equals the ratio of their
number of moles.
OD. The coefficient of the reactant tells how many product molecules
will form.
Answer:
C. The ratio of the substances coefficients equal the ratio is the number of moles
Explanation:
The ratio of the substances' coefficients equals the ratio of their
number of moles. Hence, option C is correct.
What are moles?A mole is defined as 6.02214076 × [tex]10^{23}[/tex]of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
Mole ratios are used as conversion factors between products and reactants in many chemistry problems.
The mole ratio may be determined by examining the coefficients in front of formulas in a balanced chemical equation.
Also known as the mole ratio is also called the mole-to-mole ratio.
Hence, option C is correct.
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During which change of state do atoms lose energy?
A. Sublimation
B. Freezing
C. Boiling
D. Melting
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How many Ethers were in existence at launch and why? 1. 21 million because they wanted to have more units than Bitcoin 2. 72 million because they couldn't make any less 3. 72 million because they needed to raise cash for its development 4. 21 million because they needed some to use on the testnet
Answer:
72 million because they needed to raise cash for its development
Explanation:
It is a known fact that at lunch Ethereum had only 72 million tokens in existence back in July 2015. In other to develop the Blockchain network further, the founder, Vitalik Buterin organized a fundraising event around July and August 2014.
Fast forward to the year 2020, Ether now has a total supply of about 112 million.
Look at the list of wealthy Americans under the heading “Half a Billion Back of M'Kinley."
What were the two most common industries of the business leaders on
this list?
manufacturing and carpets
banking and railroads
o jewelry and transportation
Answer:
banking and railroads
Explanation:
The two most common industries of the business leaders on this list are banking and railroads.
What are industries?
Industry is a group of productive enterprises or organizations that produce or supply goods, services, or sources of income. In economics, industries are generally classified as primary, secondary, tertiary, and quaternary; secondary industries are further classified as heavy and light.
Primary industry sector of a nation’s economy includes agriculture, forestry, fishing, mining, quarrying, and the extraction of minerals. It may be divided into two categories: genetic industry, including the production of raw materials that may be increased by human intervention in the production process; and extractive industry, including the production of exhaustible raw materials that cannot be augmented through cultivation.
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Ms. Sharkey wanted to see which tennis shoes made her run the fastest. She bought
a pair of Brooks, Adidas, and Nike and ran a mile in each to see which one gave her
the shortest time and recorded the data. What is her next step?
Answer:
to compare the data she has got?
Which of the following would have the largest pKa?
a. CH3CH2NH+3
b. C6H5NH+3
c. C6H5NH2
d. CH3CH2NH2
Answer:
CH3CH2NH3+/CH3CH2NH2 would have the largest pKa
Explanation:
To answer this question we must know Kb of CH3CH2NH2 is 5.6x10⁻⁴, and for C6H5NH2 is 4.0x10⁻¹⁰. And the CH3CH2NH3+ and C6H5NH3+ are related with these substances because are their conjugate base. That means:
pKa of CH3CH2NH3+ = CH3CH2NH2; C6H5NH3+ = C6H5NH2
Also, Kw / Kb = Ka
Thus:
pKa of CH3CH2NH3+/CH3CH2NH2 is:
Kw / kb = Ka = 1.79x10⁻¹¹
-log Ka = pKa
pKa = 10.75
pKa of C6H5NH3+/ C6H5NH2 is:
Kw / kb = Ka = 2.5x10⁻⁵
-log Ka = pKa
pKa = 4.6
That means CH3CH2NH3+/CH3CH2NH2 would have the largest pKa
2-An analysis that establishes the chemical identity of the species
A)Quantitative Analysis
B) Quantitative Synthesis
C)Qualitative Analysis
D)Qualitative Synthesis
Q1-(30 Marks) Choose the correct answer
Answer:
C Qualitative Analysis.
Explanation:
if volume stays the same, what happens to pressure?
Answer:
Pressure will stay the same if volume stays the same.
Answer:
Volume is inversely proportional to pressure, meaning if one goes up the other goes down and vise-versa. With volume remaining the same and there are no other given factors, pressure also remains the same
The noble gas electron configuration for Ca2+ ion is identical with:______.
A. Ne.
B. Kr.
C. Ca.
D. Ar.
Answer:
D. Ar.
Explanation:
The electron configuration of the atom reflects how the electrons are distributed among the various atomic orbitals. Just as for neutral atoms, we use the Pauli exclusion principle and Hund’s rule in writing the ground-state electron configurations of cations and anions.
Ions formed from atoms of most representative elements have the noble-gas outer electron configuration of ns²np⁶. In the formation of a cation from the atom of a representative element, one or more electrons are removed from the highest occupied n shell. The electron configuration of calcium and its ion is as follows:
Ca: [Ar]4s² Ca²⁺ : [Ar]
Which of the following experimental methods cannot be used to measure the rate of a reaction? Group of answer choices measurement of the absorbance of a colored reactant with time measurement of the change in the partial pressure of a gas-phase product over time measurement of the equilibrium concentration of an acidic product via titration with a strong base measurement of the absorbance of a colored product with time measurement of the change in the partial pressure of a gas-phase reactant over time
Answer:
measurement of the equilibrium concentration of an acidic product via titration with a strong base
Explanation:
The rate at which a reaction proceeds refers to how quickly the reaction is occuring. In other words, it is how quickly the reactants are changing to the products. According to the question, the rate of a reaction can be measured experimentally using the reactants' or products' properties e.g volume, pressure etc.
Since reactions must involve reactants and products, the manner in which either the reactants or products changes over time can be measured. For example; measurement of the absorbance of a colored reactant or product with time, measurement of the change in the partial pressure of a gas-phase reactant or product over time can be used.
However, a measurement of the equilibrium concentration of an acidic product via titration with a strong base will not tell us how fast the reaction is going because it is in an EQUILIBRIUM state i.e. reaction is occuring at an equal rate
Convert .0027 CL to mL.
Answer:
0.027 ml
Explanation:
[tex]1\:cl = 10\:ml\\0.0027 \: cl = x\:ml[/tex]
Cross Multiply
[tex]x = 0.027 \:ml[/tex]
The number of ATP molecules produced during the anaerobic phase of cellular respiration is _______
2
8
16
32
Answer:
The number of ATP molecules produced during the anaerobic phase of cellular respiration is 32 ATP.
Explanation:
Actually it's 36 ATP
8 from glycolysis
6 from pyruvate
24 from Krebs cycle
So total are 38 ATP but 2 ATP are consumed during glycolysis so total will be 36.
Explain why CaCl2 is likely to have properties similar to those of CaBr2
Answer:
Because both CaCl2 and CaBr2 both contain elements (Chlorine and Bromine) from the same group (group 7)
Explanation:
Elements are placed into different groups in the periodic table. Elements in the same group are those that have the same number of valence electrons in their outermost shell and as a result will behave similar chemically i.e. will react with other elements in the same manner.
Chlorine and Bromine are two elements belonging to group 7 of the periodic table. They are called HALOGENS and they have seven valence electrons in their outermost shell. Hence, when they form a compound with Calcium, a group two element, these compounds (CaCl2 and CaBr2) will possess similar properties because they have elements that are from the same group (halogen group).
The compounds of [tex]\rm CaCl_2[/tex] and [tex]\rm CaBr_2[/tex] have similar chemical properties as they are constituted of elements belonging to the same group.
The compounds with the elements belonging to the same group have similar chemical properties. It has been given that the chemical properties of elements have been dependent on the number of valence electrons.
The given compounds have been calcium chloride and calcium bromide. The calcium has been the same cation in the compounds however, the anions are different.
The anion Cl and Br both belongs to group 17 and have 7 valence electrons. Thus, the compounds have been possessing similar chemical properties.
Thus, calcium chloride and calcium bromide are more likely to have similar chemical properties as they have elements belonging to the same group.
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How do you find the average density?
Answer:
total mass divided by its total volume
Explanation:
Group of molecules which do not contain carbon
O enzymes
O inorganic compounds
O buffer
O elements
Is it possible for a diprotic acid to have Ka1?
Answer:
Yes, it is possible.
Explanation:
A diprotic acid is an acid that can release two protons. That's why it is called diprotic.
Monoprotic → Release one proton, for example Formic acid HCOOH
Triprotic → Releases three protons, for example H₃PO₄
Polyprotic → Release many protons, for example EDTA
it is a weak acid.
In the first equilibrum, it release proton, and the second is released in the second equilibrium. So the first equilibrium will have a Ka1
H₂A + H₂O ⇄ H₃O⁺ + HA⁻ Ka₁
HA⁻ + H₂O ⇄ H₃O⁺ + A⁻² Ka₂
The HA⁻ will work as an amphoterous because, it can be a base or an acid, according to this:
HA⁻ + H₂O ⇄ H₃O⁺ + A⁻² Ka₂
HA⁻ + H₂O ⇄ OH⁻ + H₂A Kb₂
Which of the following is an example of a chemical change
A. apple slices turn brown
B. toast burns
C. silver tarnishes
D. all of these are chernical changes
Answer:
D. all of these are chemical changes
Where did I go wrong? I know the 2.58 is the right answer but where did I go wrong in my work? Please help!!
Answer: See below
Explanation:
In this problem, conversion factors are very important. In the second conversion, you wrote 1 kg=0.001 g. This is incorrect. It should be 1 kg=1000g. Otherwise, the rest is correct. Make sure to have correct conversions. The answer will be correct.
PLEASE ANWSER FAST! Gus is performing an experiment on cells. First he places the cells in a container of water and salt. When he checks some of the cells under a microscope, he sees that they are beginning to shrivel. What would most likely stop the cells in the liquid from shriveling? adding more water to the container adding more salt to the container increasing the number of cells in the container decreasing the number of cells in the container
Answer:
adding more water to the container
Explanation: because it would cause it to soak up the fluid to created a substance again
Answer:
adding more water to the container and iflamates the cells
Explanation:
What was Albert Einstein's contribution to our understanding of the
photoelectric effect?
A. He described the relationship between energy and mass.
B. He described photons as little packets of electrons.
C. He described electricity as moving electrons.
D. He described light as little packets called photons.
Answer: The Answer Is D, He described light as little packets called photons.
Explanation:
The contribution of Albert Einstein to our understanding of the photoelectric effect is he described light as little packets called photons. The correct option is D.
Who is Albert Einstein?The theory of relativity, which Albert Einstein developed and is rightfully famous for, transformed our understanding of space, time, gravity, and the cosmos.
Along with his work on relativity, the physicist established the scientific principles behind items like paper towels, lasers, and other everyday items.
Since Einstein first suggested using the use of light quanta to clarify the photoelectric impact, quantum theory accurately portrays the photoelectric impact. The quantum theory of radiation gives this concept a formal formulation.
Therefore, the correct option is D. He described light as little packets called photons.
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how do you make chocolate milk
Metal atoms always form a cation of a single, specific charge.
a.) True, because metal atoms form ionic compounds of a known composition.
b.) False, because some metal atoms are known to have more than one possible positive charge.
c.) True, because nonmetal atoms always form anions of a single, specific charge.
d.) True, because metal atoms lose all of their valence electrons.
e.) False, because elements in different rows of the periodic table can form different cations.
Answer:
c.) true, because nonmetal atoms always form anions of a single , specific charge
how do you convert wavelength to frequency?
Answer:
Image result for how do you convert wavelength to frequency?
How do you calculate energy from wavelength?
Convert your wavelength into meters.
Divide the speed of light, ~300,000,000 m/s, by the wavelength in m. This gives you the wave's frequency.
Multiply the frequency by Planck's constant, 6.626 x 10-34. The result is the waves energy in joules (J).
Explanation:
Water that is heated move
PLS HELP !!!
Answer:
it moves faster when heated
Answer:
the answer is faster
Explanation:
why because water moves faster when heated
Determine the mass in grams of 2.98 × 10²¹ atoms of arsenc. Determine the mass in grams of 2.98 × 10²¹ atoms of arsenc.
Answer:
37.1 g of Arsenic
Explanation:
2.98 x 10^21 atoms of Arsenic x 74.92g/6.02 x 10^23
= 223.26 x 10^21/6.02 x 10^23
= 2.2326 x 10^23/6.02 x 10^23
= 37.1 g of Arsenic
12.A piece of magnesium is in the shape of a cylinder with a height of 5.62 cm
and a diameter of 1.34 cm. If the magnesium sample has a mass of 14.1 g, what
is the density of the sample?
Answer:
Density, d = 1.779 g/cm³
Explanation:
The density of a material is given by its mass per unit volume.
Here, height of a piece of magnesium cylinder, h = 5.62 cm
Its diameter, d = 1.34 cm
Radius = 0.67 cm
Volume of he cylinder,
[tex]V=\pi r^2 h\\\\\text{Putting the value of r and h, we get :}\\\\V=(\pi \times (0.67)^2\times 5.62)\ cm^3[/tex]
[tex]d=\dfrac{m}{V}\\\\d=\dfrac{14.1\ g}{(\pi \times (0.67)^2\times 5.62)\ cm^3}\\\\d=1.779\ g/cm^3[/tex]
So, the density of the sample is 1.779 g/cm³.
A submarine took 9 hours to complete a journey. For the first 5 hours, it traveled at an average speed of 106km/h. For the rest of the journey, it traveled at an average speed of 125km/h. What was the total distance of the journey?
The correct answer is 1030 km
Explanation:
The distance a body such as a submarine travels depends on two main variables the time of the movement and the speed. Indeed, to calculate the distance it is possible to use the formula d = s x t. The process to calculate the distance of the submarine journey is shown below:
Distance in the first part of the journey:
It is known during the first part of the journey the submarine traveled 5 hours at a speed of 106 km/h
Distance = speed × time
D = 106 km/h × 5 h
D = 530 km
Distance in the second part of the journey:
During the remaining 4 hours (the first part took 5 hours and the total time traveled were 9 hours) the speed was 125km/h. Now, let's calculate the distance covered during this part of the journey
Distance = speed × time
D= 125 km/h × 4 h
D= 500 km
Total distance:
Finally, add both distances to know the total distance
530 km + 500 km = 1030 km
In the density of a liquid activity, the graph had an intercept. If you were to make a similar graph using metal blocks, would the graph have an intercept?
Answer:
NO
Explanation:
It would be difficult to plot a line of best fit on the scattered graph of the activities of metal blocks as the activities would almost be the same horizontally on the graph and an attempt to draw/determine an intercept will be almost impossible. The line of best fit is usually drawn to determine the relatedness/correlation of the variables.
Drawing intercept for the activities of the liquid is easier because a line of best fit can be easily placed between the clustered liquid activities on the scattered plot.