Answer:
I also have this question but see the 69 page of ur question book
A sample of radioactive material starts with 80 grams. After 3 half-lives have passed, how much radioactive sample remains?
Answer:
I want to say 10 grams
Explanation:
80 grams is your start
and a half-life is half of that so...
half of 80 ( and or 80/2)
40 grams
then another half is...
half of 40 (and or 40/2)
20 grams
then another half-life is...
half of 20 (and or 20/2)
10 grams
That is 3 half-life of 80 grams
*becareful not to just divide 80 / 3 you will get 26.666 (repeating) that is incorrect
you want a half of a half of a half
fill in the blank please
amino acids as _____ are to words
Answer:
Sentences are where there is a beginning and an end of a section of a paragraph. Letters are individual parts of sentences.
The answer that would make the MOST sense would be SENTENCES
Calculate the energies of the n=2 and n=3 states of the hydrogen atom in Joules per
atom
Answer:
See Explanation
Explanation:
Positional Energy for electron as function of principle energy level (n)
=> Eₙ = -A/n²; A = 2.18x10⁻¹⁸J
Positional Energy for electron in n=2 => E₂ = -2.18x10⁻¹⁸/(2)² = -5.45x10⁻¹⁹J
Positional Energy for electron in n=3 => E₃ = -2.18x10⁻¹⁸/(3)² = -2.42x10⁻¹⁹J
ΔE(n=3→2) = -5.45x10⁻¹⁹J - (-2.42x10⁻¹⁹J) = -3.03x10⁻¹⁹J
Which of these elements is the most ductile?
a. vanadium
b. mercury
c. germanium
d. astatine
e. xenon
Answer:
mercury
Explanation:
How many moles are in 11.0 grams of methane (CH4)?
Which electron dot diagram represents H2?
Answer:
H:H
Explanation:
Question 4 of 35
What did Thomson discover as a result of his experiments with cathode ray
tubes?
A. Electrons are found within electron clouds of atoms.
B. Each atom has a positive nucleus at its center.
C. Electrons travel along circular paths within atoms.
D. Atoms are made up of smaller subatomic particles
Answer:
D
Explanation:
Answer:
D Atoms are made up of smaller subatomic particles
Explanation:
I just took the quiz, I hope this helps!
6. Which scientific law is best demonstrated by the reaction shown in the diagram?
2H2 + O2-2H20
Hydrogen Oxygen Water
ALA
law of universal gravitation
law of angular momentum
law of conservation of energy
law of conservation of mass
Answer:
law of conservation of mass
Explanation:
According to the law of conservation of mass, mass is neither created nor destroyed.
This is actually the law that guides the balancing of chemical reaction equations.
On the left side we have four atoms of hydrogen and two atoms of oxygen. Exactly the same number of atoms of each element is seen on the right hand side in accordance with the law of conservation of mass.
Plz help ASAP
Plz and ty
Answer:
It's circulatory system
Hope it's help ^_^
Answer: circilutory
Explanation:
Write
the following separation techniques?
a. Filtration
b. Evaporation
C. Fractional distillation
d. Chromatography
Answer:
Explanation: Fractional distillation
Find the volume of
this object.
5 cm
5 cm
5 cm
A
15 cm3
B
125 cm3
C
30 cm3
Answer: B. [tex]125\ cm^3[/tex].
The volume of the given object = [tex]125\ cm^3[/tex]
Explanation:
Given : Dimensions of an object : 5 cm x 5 cm x 5 cm [ it is a cube with all equal sides]
Formula to find the volume of a cube = [tex](side)^3[/tex]
[tex]=5^3\ cm^3=125\ cm^3[/tex]
Hence, the volume of the given object = [tex]125\ cm^3[/tex]
Therefore , the correct option is B. [tex]125\ cm^3[/tex].
1s2 3s2 3p6 3s2 3p6 3d6 4s2 what is element
The element with the electron configuration, 1s2 3s2 3p6 3s2 3p6 3d6 4s2, will be iron.
Atomic number and electronic configurationsIn the electronic configuration of elements, the number of electrons possessed by the element is shared into the orbitals according to their energy levels.
The electrons are first shared in orbitals in the same energy level before pairing starts.
Also for neutral atoms, the number of electrons is equivalent to the number of protons. The number of protons in itself represents the atomic number of elements.
Thus, considering this electron configuration, 1s2 3s2 3p6 3s2 3p6 3d6 4s2; the total number of electrons in all the orbitals is 26. The element with the atomic number of 26 is iron.
More on electron configurations can be found here: https://brainly.com/question/14283892
#SPJ1
why can a solution be classified as a mixture
Which process is constructive?
A:Water wears away rocks in a river.
B:Wind removes sand from a beach.
C:volcano forms an island in the ocean.
D:An earthquake breaks apart a cliff on a mountain.
What mass of calcium chloride is required to prepare 3.20 L of 0.850 M of calcium chloride solution?
Answer:
301.92 g of CaCl2.
Explanation:
The following data were obtained from the question:
Volume of CaCl2 solution = 3.20 L
Molarity of CaCl2 solution = 0.850 M
Mass of CaCl2 =?
Next, we shall determine the number of mole of CaCl2 in the solution. This can be obtained as illustrated below:
Volume of CaCl2 solution = 3.20 L
Molarity of CaCl2 solution = 0.850 M
Mole of CaCl2 =?
Molarity = mole /Volume
0.850 = mole of CaCl2 /3.20
Cross multiply
Mole of CaCl2 = 0.850 × 3.20
Mole of CaCl2 = 2.72 moles
Finally, we shall determine the mass of the CaCl2 needed to prepare the solution as follow:
Mole of CaCl2 = 2.72 moles
Molar mass of CaCl2 = 40 + (2×35.5)
=40 + 71
= 111 g/mol
Mass of CaCl2 =?
Mole = mass /Molar mass
2.72 = mass of CaCl2 /111
Cross multiply
Mass of CaCl2 = 2.72 × 111
Mass of CaCl2 = 301.92 g
Therefore, 301.92 g of CaCl2 is needed to prepare the solution.
1. (solution/solvent/solute) Use the correct word in the following sentence:
dissolved in
makes up a
2 What is the difference between a strong electrolyte and a weak electrolyte?
3. The solubility of sodium chlorate in water is 52g/100g H20. If 0.46 moles of sodium
chlorate are dissolved in 60g of water, is this solution
saturated/supersaturated/unsaturated?
Answer:
1. solute dissolved in solvent makes up a solution.
explain 5 the major innovation made from Abacus to the present fifth generation
Answer:
The major innovation made from Abacus to the present fifth generation is explained below in details.
Explanation:
Industrial Age - 1600
John Napier, a Scottish noble and diplomat consecrated much of his holiday time to the learning of mathematics. He was particularly engrossed in devising methods to aid estimates. His most famous offering was the discovery of logarithms. He listed logarithmic measures on a set of 10 board rods and thus was capable to do multiplication and division by equaling up numbers on the poles. These became recognized as Napier’s Bones.
What is the atomic number of this atom?
6
8
9
16
The atomic number of this atom : 8
Further explanationGiven
Atomic model (attached)
Required
The atomic number
Solution
To determine the atomic number of an element, we can look at the number of electrons or the number of protons, because
atomic number = number of protons = number of electrons in neutral atoms
While the mass number is the number of neutrons + the number of protons located in the atomic nucleus
The charge of each of these atomic sub particles:
electron: charge -1proton: charge +1neutron: not charged / 0If we look at this atomic model, there are 8 electrons in the shell, consisting of 2 electrons in the first shell and 6 electrons in the second shell (which can also be called valence electrons)
Whereas in the atomic nucleus there are 8 protons and 10 neutrons
Answer:8
Explanation:
How many
electrons does Oravetium contain
Im hvaing a hard time getting the right answer
1. If 2.49 g of CuNO3 is dissolved in water to make a 0.830 M solution, what is the volume of the solution in milliliters?
.01599 and 15.99 is wrong and I think Im doing the equation wrong, help!
Answer:
[tex]V=23.9mL[/tex]
Explanation:
Hello!
In this case for the solution you are given, we first use the mass to compute the moles of CuNO3:
[tex]n=2.49g*\frac{1mol}{125.55 g}=0.0198mol[/tex]
Next, knowing that the molarity has units of moles over liters, we can solve for volume as follows:
[tex]M=\frac{n}{V}\\\\V=\frac{n}{M}[/tex]
By plugging in the moles and molarity, we obtain:
[tex]V=\frac{0.0198mol}{0.830mol/L}=0.0239L[/tex]
Which in mL is:
[tex]V=0.0239L*\frac{1000mL}{1L}\\\\V=23.9mL[/tex]
Best regards!
Which of the following would be most useful in trying to obtain procedural information to replicate an experiment previously published?
Answer: Peer-reviewed journal article is the most useful because the information in them had been carefully scrutinized and aproved by people who are experts in that particular field.
Which of the following is NOT a property of sodium
1. Sodium is a reactive METAL
2. Sodium is very SOFT
3. Sodium is a reactive GAS
4. Sodium forms a WHITE coating
Answer:
3
Explanation:
Sodium is not a gas, it is a Alkali Metal. I recommend studying the sections of the periodic table to help remember what each element should be.
Hope this helps.
Help me with this . I'm bad at chemistry . I’ll give you a brain list . Don’t answer if u don’t know at all .
Answer:
2.
a.Sodium bromide
b. Magnesium dichloride
c. Lithium iodide
not sure about 3 or 4 sry
explain the early theories of the atomic structure
Hi
i hope this helps
Answer:
The Greek atom theory
Explanation:
The concept of the Greek atomos theory is an indivisible particle of matter, goes back to ancient Greece and a man named Democritus held that all matter could be subdivided only until some finite particle was reached.
what's the formula for na and f , ca and br , mg and O
Answer:
NaF, CaBr2, MgO
Explanation:
Hi! For this problem, you are going to want to look at the charges of the elements in order to write their formulas.
NaF: Na has a charge of +1 and F has a charge of -1. This means that they have a 1:1 ratio and the formula is written as such - NaF.
CaBr2: Ca has a charge of +2 and Br has a charge of -1. For this problem you want to make sure that their formal charge (the charge of the entire molecule) equals 0. This means that the negative charges need to equal the positive charges. Looking at this, you are going to need to Br ions with a charge of -1 to equal one Ca ion with a charge of +2 - CaBr2.
MgO: Mg has a charge of +2 and O has a charge of -2. This means that they have a 2:2 ratio which simplifies to a 1:1 ratio and the formula is written as such - MgO.
Hope this helps!
Could someone pls help me :)
liquid 1 and 2 have the same color and mass so the answer would be liquid 1 and 2
Explanation:
hope this is helpful
Please help Fast I do not know
Answer:
So the answer to this question would be C. 400 J
Explanation:
Now for this problem, what is given is a 40 Newtons which would represent the force to be applied to the object, and a distance of 10 meters after the application of the said force. When these two combine, work is done. The unit for work is Joules and this is what we are looking for. The formula to get Joules or for work would be the force applied to the object multiplied by the distance that it travelled after the application of the force. It looks like this
work = force x distance
Joules = Newtons x meter
so let us substitute the variables to their corresponding places
Joules = 40 N x 10 m
Joules = 400 J
IF THIS HELPED YOU PLEASE MARK ME BRAINLIEST! THANKS! :)))))
What is the concentration in mol L-l of a 12% solution of tetrahydrate magnesium chloride (MgCl2)?
Mg = 24.31 g mol-1
Cl = 35.45 g mol-1
H = 1.01 g mol-1
O = 16.00 g mol-1
The concentration in mol L-l (M) = 0.717
Further explanationGiven
12% solution of tetrahydrate magnesium chloride (MgCl₂)
Required
The concentration
Solution
Tetrahydrate magnesium chloride (MgCl₂)⇒MgCl₂.4H₂O
MW = Ar Mg+2. Ar Cl+8. Ar H + 4. Ar O
MW=24.31 + 2 x 35.45 + 8 x 1.01 + 4 x 16
MW=24.31+70.9+8.08+64
MW=167.29 g/mol
12% solution = 12 % m/v = 12 g in 100 ml solution
For 1 L solution :
[tex]\tt \dfrac{1}{0.1}\times 12~g=120~g[/tex]
The concentration in g/L = 120 g/L
Convert grams to moles :
[tex]\tt mol=\dfrac{120}{167.29}=0.717[/tex]
which event would most likely lead to a thunderstorm g i v i n g b r a i n l e s i t
Answer:
A
Explanation:
I took a test like this and my teacher said this was right so ye. hopefully I remembered correctly if its wrong im sorry ;C
Answer: A
Explanation: A thunderstorm forms when warm, moist air rises into cold air. Hope this helps. :)
Cups ans glasses are taking too long to air dry. This could be caused by
Answer: Servsafe 9
Explanation:
Remove food from the surface
clean the surface
rinse the surface
sanitize the surface
allow the surface to air dry
Cups and glasses are taking too long to air dry. This could be caused by the ventilation system not working properly. The correct option is D.
What is ventilation?A ventilation system is a mechanical device that is normally created and built to supply airflow into and out of a structure or other enclosed space. Because air is provided by a functioning ventilation system, moisture on surfaces like cups and glasses can dry more quickly.
It is possible to describe air-drying as a technique or process for removing moisture from surfaces using either heated, forceful, or dry air. Therefore, air drying aids in making the surface of goods like cups and glasses dry, or free of moisture.
Thus, the correct option is D. The ventilation system not working properly.
To learn more about ventilation, refer to the link:
https://brainly.com/question/8295680
#SPJ2
The question is incomplete. Your most probably complete question is given below:
A. Incorrect timing of the wash cycle.
B. An improper use of chemical sanitizer.
C. The water temperature being too high.
D. The ventilation system not working properly.