Answer:
Part A. p, n = 31, 38.
Part B. p, n = 31, 40.
Part C. [tex]^{69}_{31}Ga,\ ^{71}_{31}Ga[/tex]
Explanation:
Hello,
Part A.
In this case, since the atomic number for gallium is 31, we can say that the first isotope has also 31 protons and the neutrons are computed by using its molar mass as a whole number (69):
[tex]neutrons=mass-protons=69-31=38[/tex]
Thus, result is p, n = 31, 38.
Part B.
In this case, since the atomic number for gallium is 31, we can say that the second isotopes has also 31 protons and the neutrons are computed by using its molar mass as a whole number (71):
[tex]neutrons=mass-protons=71-31=40[/tex]
Thus, result is p, n = 31, 40.
Part C.
Finally, the isotopes as shown as:
[tex]^{69}_{31}Ga,\ ^{71}_{31}Ga[/tex]
Best regards.
To prepare a sample in a capillary tube for a melting point determination, gently tap the tube into the sample with the_____________
a) open,
b) closed end of the tube down.
Continue tapping until the sample____________
a) completely fills the tube
b) is a couple millimeters high,
c) has a single crystal in the tube.
Then, with the _________
a) closed,
b) open end of the tube down,
tap the sample down slowly or ________
a) heat the tube up,
b) drop the tube into a longer tube,
c) shake the tube in the air to move the sample down faster.
Answer:
1. A
2. B
3. A
4. B
Explanation:
In Chemistry, one of the ways to test for the purity of a substance is to determine its melting point. Generally, a pure substance has its melting point between the temperature range of 1 - 2 (°C). In order to determine the melting point of a substance, we can use the procedure stated below;
To prepare a sample in a capillary tube for a melting point determination, gently tap the tube into the sample with the open end of the tube down. Continue tapping until the sample is a couple millimeters high. Then, with the closed end of the tube down, tap the sample down slowly or drop the tube into a longer tube. Lastly, you should ensure that you can see some or perhaps all of the sample in the viewfinder (magnifier) when it is placed on the melting point apparatus, then you can turn on the heat.
Additionally, in taking your readings, you should record the temperature for when the melting starts to when it ends.
chemist must prepare of hydrobromic acid solution with a pH of at . He will do this in three steps: Fill a volumetric flask about halfway with distilled water. Measure out a small volume of concentrated () stock hydrobromic acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrobromic acid that the chemist must measure out in the second step. Round your answer to significant digits.
Answer:
32 mL
Explanation:
A chemist must prepare 500.0mL of hydrobromic acid solution with a pH of 0.50 at 25°C. He will do this in three steps: Fill a 500.0mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (5.0M) stock hydrobromic acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrobromic acid that the chemist must measure out in the second step. Round your answer to 2 significant digits.
Step 1: Calculate [H⁺] of the dilute solution
pH = -log [H⁺]
[H⁺] = antilog -pH = antilog -0.50 = 0.32 M
Step 2: Calculate [HBr] of the dilute solution
HBr is a strong acid that dissociates according to the following equation.
HBr ⇒ H⁺ + Br⁻
The molar ratio of HBr to H⁺ is 1:1. The concentration of HBr is 1/1 × 0.32 M = 0.32 M.
Step 3: Calculate the volume of the concentrated HBr solution
We will use the dilution rule.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 0.32 M × 500.0 mL / 5.0 M
V₁ = 32 mL
Dmitri Mendeleev and Henry Moseley developed their periodic tables about forty years apart. During that time, many discoveries in chemistry were made. Which fact was most likely discovered between the time of Mendeleev’s table and the time of Moseley’s table that helped Moseley develop his version? Atomic mass is the average mass of different samples of the same element. Different elements can have similar chemical properties even if their atomic masses are different. The number of protons in an atom is different than the atom’s total mass. Protons strongly affect an element’s atomic mass, while the electrons in atoms do not.
Answer:
The first one I think
Explanation:
Answer:
Its C
Explanation:
Which of the following best describes the discovery of the atom?
Its existence was hypothesized based on observations of larger samples of matter.
O Its existence was proven with the understanding of quantum mechanics.
O Its existence was determined by an English scientist studying nature.
Its existence was established after the invention of the microscope.
Answer:
Its existence was determined by an English scientist studying nature.
Its existence was established after the invention of the microscope.
Explanation:
I know because atoms are made up by a scientist study chemicals while trying to learn about atoms as well.
Its existence was hypothesized based on observations of larger samples of matter best describes the discovery of the atom. Therefore, option A is correct.
What is an atom ?A chemical element is uniquely defined by its atoms, which are tiny pieces of substance. An atom is made up of a core nucleus and one or more negatively charged electrons that orbit it. The positively charged, comparatively hefty protons and neutrons that make up the nucleus may be present.
But when it comes to the name atom, we must travel back to 400 B.C. ancient Greece. The Greek word atomos, which meaning "uncuttable," was proposed by Democritus, a renowned philosopher. In the end, all matter could be reduced to distinct, tiny particles, or atomos, he said.
Atoms are made up of a nucleus in the middle that is surrounded by protons, neutrons, and electrons.
Thus, option A is correct.
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1pt Which part of the scientific method helps you figure out what you've learned?
O A. Predict
OB. Observe
O C. Design
O D. Analyze
An object has a variable volume and shape before it changes state. After the
change, it can still change in shape but has a fixed volume. Which change of
state has occurred
According to the concept of forces of attraction , the change of state that has occurred is gas to liquid.
What are forces of attraction?Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
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What is the correct chemical formula for Fe3+ and P3-
Answer:
FeP, which is iron (III) phosphide.
Explanation:
Hello,
In this case, when iron (III) ion and phosphide ion react, the following compound is formed as the charges are exchanged to each other at the subscripts:
[tex]Fe^{3+}+P^{3-}\rightarrow Fe_3P_3[/tex]
Yet, since the three could be simplified to 1 at both Fe and P, we obtain:
[tex]Fe^{3+}+P^{3-}\rightarrow FeP[/tex]
Which is known as iron (III) phosphide.
Best regards.
Why is the atomic mass of iron, 55.845 amu, most similar to the mass of iron-56, yet less than 56 amu? The atomic mass is the simple average of the masses of the two most abundant isotopes. Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56. The second most abundant isotope is iron‑54, which reduces the atomic mass to less than 56 amu. The atomic mass is the weighted average of the masses of all of the isotopes. Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56. The second most abundant isotope is iron‑54, which reduces the atomic mass to less than 56 amu. The atomic mass is the weighted average of the masses of the two most abundant isotopes. Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56. The second most abundant isotope is iron‑54, which reduces the atomic mass to less than 56 amu. The atomic mass is the simple average of the masses of all of the isotopes. Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56. The second most abundant isotope is iron‑54, which reduces the atomic mass to less than 56 amu.
Answer:
Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56.
Explanation:
The atomic abundance of the isotopes of Iron is:
⁵⁴Fe: 5.82%
⁵⁶Fe: 91.66%
⁵⁷Fe: 2.19%
⁵⁸Fe: 0.33%
Where the Iron-56 is the most abundant isotope of Iron atom
As atomic mass is defined as the sum of the masses of the ions multiplied by its abundance, and the Iron-56 is the most abundance isotope, the atomic mass of Fe most be similar to the ⁵⁶Fe mass because is the most abundant isotope.
Right option is:
Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56.Iron‑56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iron‑56.
the atomic abundance of the isotopes of Iron is:
⁵⁴Fe: 5.82%
⁵⁶Fe: 91.66%
⁵⁷Fe: 2.19%
⁵⁸Fe: 0.33%
Since the Iron-56 is the most abundant isotope of the Iron atom
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Which of the following is true?
O The exact position of an electron can be known.
O Electron clouds have the same energy levels.
O Electrons in a cloud have probable locations.
O Electrons are positively charged.
Answer:
B. O The electron cloud have the same energy levels.
Nonmetals are ___.
O part of group 18
O are always gases
O good conductors of heat
O poor conductors of heat
Answer:
D. Poor conductors of heat
Explanation:
What is the limiting reactant in the following reaction if 1.63g of NH3 is reacted with 3.47g of Cl2 ?
4 NH3 + 3 Cl2 → 3 NH4Cl + NCl3
a. Cl2
b. NCI3
c. NH4Cl
d. NH3
Answer:
B
Explanation:
you will have to find the number of moles for each 4Nh3 and 3cl2
4NH3
m= 1.63
mr= 14+1x3= 17
n.of moles = 1.63/17=0.09588
3CL2
m=3.47
mr=35.5x2=71
nof moles = 3.47/71= 0.04887
after getting the number of moles you will divide your answer by its ratio
4NH3 3CL2
0.09588/4=0.02397 0.04887/3= 0.0133
the smaller number will be the limiting reagent while the bigger number is the excess reagent
How can density be used to determine the identity of a pure substance?
Answer:
Explanation:
You can identify an unknown substance by measuring its density and comparing your result to a list of known densities. Density = mass/volume. Assume that you have to identify an unknown metal.
Fill in the blank with the correct response:
The ______________ contains all the water on Earth and is why Earth is referred to as the blue planet.
A.magnetosphere
B.hydrosphere
C.atmosphere
D.lithosphere
A liquid has a density of 16 g/mL. If you have 0.21 mL of liquid, what what is mass be
Answer:
The answer is 3.36 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume of liquid = 0.21 mL
density = 16 g/mL
The mass of the liquid is
mass = 0.21 × 16
We have the final answer as
3.36 gHope this helps you
Mercury(II) oxide decomposes to form mercury and oxygen, like this:
2HgO(s)--------Hg(l) + O2(g)
At a certain temperature, a chemist finds that a reaction vessel containing a mixture of mercury(II) oxide, mercury, and oxygen at equilibrium has the following composition:
compound amount
HgO 24.0g
Hg 23.6g
O2 22.7g
Calculate the value of the equilibrium constant for this reaction. Round your answer to significant digits.
Answer:
[tex]Kc=0.71=7.1x10^{-1}[/tex]
Explanation:
Hello,
In this case, since the equilibrium constant is written including gaseous and aqueous species only, for this reaction, it is:
[tex]Kc=[O_2][/tex]
Thus, since the volume is missing, we are going to assume 1 L, but you can change it based on the one you are given, thus, the concentration of oxygen at equilibrium is:
[tex][O_2]=\frac{22.7g*\frac{1mol}{32g} }{1L} =0.709M[/tex]
It means, that the equilibrium constant, with two significant figures is:
[tex]Kc=0.71=7.1x10^{-1}[/tex]
Best regards.
How do you test color?
Be sure to answer all parts. The following IUPAC name is incorrect. Which of the following is the best explanation for why the name is incorrect? 3−butyl−2,2−dimethylhexane The longest chain was not chosen. The compound is spelled incorrectly. The compound is alphabetized incorrectly. The compound has incorrectly labeled substituents. Correct the name: 1−ethyl−1−tert−butylpentane 4−tert−butyloctane (1,1,1−trimethyl)−sec−butylpentane tert−butyloctane
Answer:
Which of the following is the best explanation for why the name is incorrect?
- The longest chain was not chosen.
- 4−tert−butyloctane
Explanation:
Let's think in the condensed formula:
CH₃C(CH₃)₂CH((CH₂)₃CH₃)CH₂CH₂CH₃.
We see that in the second carbon, we have two methyls and in the third carbon a butyl group.
But the name is incorrect because the longest chain was not chosen.
For IUPAC rules we have to determine:
- The longest main chain.
- From two chains of equal length, we may choose the most branched chain.
- It must be numbered starting from the end that has the closest branch.
- Each remainder is named as a substitute for the main chain
If we draw the alkane we have:
CH₃
|
CH₃ - C - - CH - - CH₂ -- CH₂ -- CH₃
| |
CH₃ CH₂
|
CH₂
|
CH₂
|
CH₃
The carbon in black, is the first carbon, if we start to number from the underlined carbon, we would have the first branch at carbon 5. We have 8 carbons, so if we start to count from the black carbon (carbon 1), the branch will be at the carbon 4, that's the main chain.
So finally, at the carbon 4 we have a tertiary carbon (it is a single carbon which is joined with 3 others carbons, and the single carbon is it joined to the main chain). That is the tert-butyl group.
As it is in the fourth position, we can say that the alkane's name is 4−tert−butyloctane.
Notice that tert-butyl is a common name but it is available by IUPAC.
What volume (in mL) of a 0.150 M HNO3 solution will completely react with 35.7 mL of a 0.108 M Na2CO3 solution according to the following balanced chemical equation?
Na2CO3(aq)+2HNO3(aq)→2NaNO3(aq)+CO2(g)+H2O(l)
In the reaction in Part A, what mass (in grams) of carbon dioxide forms?
Answer:
Explanation:
where are the anwser choices
Answer:
First part: volume of HNO3 solution = 51.4 mL
Second part: mass of CO2 = 0.170 g
Explanation:
First part:
Based on the volume and concentration of the Na2CO3 solution, there is 3.86 mmol of Na2CO3 available to react with HNO3 . Considering the stoichiometric relationship, you then calculate the volume of a 0.150 M solution that contains 7.71 mmol of HNO3 .
51.4 mL
Second part:
Since the reactant and product have a stoichiometric relationship that is 1:1, 0.00386 mol of Na2CO3 can react to form 0.00386 mol of CO2 . The molar mass of CO2 (44.01 g/mol ) is then used to convert the moles to the corresponding mass in grams.
0.170 g
When a piece of zinc metal is carefully placed in a beaker of strong acid, bubbles form on the surface of the metal and begin to rise to the surface.
The bubbles most likely indicate that
A.
a new substance is being produced.
B.
the zinc metal is melting.
C.
the acid solution is boiling.
D.
a physical change is occurring.
Answer:
A. a new substance is being produced.
Explanation:
The bubbles most likely indicates that a new substance is being produced by this reaction. In essence, we describe this sort of change as chemical change.
In a chemical change, new substances are usually produced. They are accompanied by the evolution or absorption of energy.
The reaction of Zinc with a strong acid to produce bubbles on the surface of the metal indicates a chemical change and the formation of a new kind of substance.
Take for example, let zinc reacts with hydrocholoric acid, HCl;
Zn + 2HCl → ZnCl₂ + H₂
Since Zn is higher than Hydrogen in the activity series, it will displace it from HCl and liberate hydrogen gas as a product. This will cause the bubbles observed in the reaction.
This is a chemical change and new products have been formed.
B and D are wrong because they are both physical changes.
C is wrong because no information about such is provided by the problem statement.
So, when a piece of zinc metal combines with a strong acid, a new kind of substance is produced.
Why are measurements always at least a little uncertain?
Answer:
because measuring instruments have an uncertainty of +-1 or mor
Question 1
Ernest Rutherford completed his famous gold foil experiment in 1911. In this experiment, alpha particles were fired at a thin sheet of gold foil. He observed that most of the alpha particles passed straight through the gold foil unimpeded, but a small number of alpha particles were deflected. Which of the following conclusions about atomic structure were made from Rutherford’s gold foil experiment?
Answer: gold foil. It's in the experiment's name
When liquid gold becomes a solid, its particles get closer together. Which best describes what happened to the gold?
the conservation of magnetism
the change in solubility in a physical change
the change in melting point in a physical change
the rearrangement of particles in a physical change
Answer:
The rearrangement of particles in a physical change
Explanation:
Hello.
In this case, since phase transitions are physical changes in which the molecules of a substance in any phase rearrange in order to form another phase of the same substance, we can see that for gold when passing from liquid to solid, which is a process called freezing, the initial liquid gold has the particles not-so-close but also not-so-far to each other with a messy arrangement with lack of order as well but the final solid gold has a very organized network of particles, we can infer that the best statement describing such change is the rearrangement of particles in a physical change. You can verify the particles arrangement on the attached picture.
Best regards.
Answer:
yes d is the answer
Explanation:
Determine the volume of an object that has a mass of 441 g and a density of 21 g/cm3.
Answer: 21cm^3
Explanation:
Volume Formula:
Mass / Density = Volume
441g/21g/cm^3 = 21cm^3
what makes calcium and nitrogen different list two differences
Answer:
the difference in electronegativity is so large (2.04) that the bonding electrons spend almost all their time on the nitrogen atom.
Explanation:
Because calcium loses 2 electrons to become Ca2+, and nitrogen gains 3 electrons to become N3−, you need two calcium atoms and three nitrogen atoms in order to form a neutral compound.
3. When two or more substances are physically combined, the result is a(n)
A. chemical change. B. element
C. compound
D. mixture
This section of the periodic table is called a(n)
Answer:
Is it Group?
Explanation:
PLEASE HELP ASAP WILL GIVE BRAINLIEST!!!
what is the volume of a rock in cubic cm (cm3^) with a mass of 156g and a known density of 1.93 g/cm3^
Answer:
301.08 cm^3
Explanation:
v=m×d
156g×1.93g/cm^3
Answer:
The answer is 301.08
Explanation
I hope this helps! I know this is the right answer I took the test! Can I get brainliest?
While running, leg muscles work to move leg bones, and the skin helps to
Answer:regulating body temperature
Explanation:
how does adding energy to an atom affect its electrons
A sea turtle is 3feet below the surface of the sea ??? Help me ple
