When the first periodic table of the elements was published, the elements were arranged by atomic mass. Although
several elements seemed out of order, later discoveries showed the order to be correct.
Which event most likely helped the development of the periodic table?
O Scientists changed the atomic masses to better fit the pattern.
O Scientists refused to consider other ways to organize the elements.
O New technology was developed that modified the masses.
O New information changed the understanding of the atom's structure.
ANSWER ASAP
Which is the best way to determine if an object is made of pure silver?
O Determine the solubility of the object.
O Test to see if the object is chemically reactive.
Determine the density of the object and compare the known density of pure silver.
O Compare the mass of the silver object to the mass of a piece of pure silver.
Answer:
The correct option is;
Determine the density of the object and compare the known density of pure Silver
Explanation:
The density of the object is found by finding the weight of the object, and then finding the volume (of water) the object displaces when it is immersed (in water)
The density is then fond by dividing the weighed mass by the volume the object displaces when immersed
Compare the result of the measured density with that of pure silver. If the two have density, as well as other similar physical characteristics, then the object is likely to be pure silver.
Determine how you would prepare 220 mL of a 0.500 M potassium hydroxide solution starting with: a) solid potassium hydroxide b) a 1.25 M potassium hydroxide solution
Answer:
a) 6.17 g of solid KOH
b) 88.0 mL of a 1.25 M potassium hydroxide solution
Explanation:
a) We have to determine the mass of solid potassium hydroxide that has to be weighed to prepare 220 mL of a 0.500 M potassium hydroxide solution. We will also require the molar mass of potassium hydroxide, KOH, 56.11 g/mol.
0.220 L × (0.500 mol/L) × (56.11 g/mol) = 6.17 g
b) We will use the dilution rule to determine the volume of the 1.25 M potassium hydroxide solution to be measured.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 0.500 M × 220 mL / 1.25 M = 88.0 mL
When copper is bombarded with high-energy electrons, X rays are emitted. Calculate the energy (in joules) associated with the photons if the wavelength of the X rays is 0.154 nm.
Answer:
E = 12.92 × 10^(-16) J
Explanation:
Formula for energy is;
E = hc/λ
Where;
h is Planck's constant = 6.63 x 10^(-34) J.s
c is speed of light = 3 × 10^(8) m/s
λ is wavelength = 0.154 nm = 0.154 × 10^(-9) m
E = (6.63 x 10^(-34) × 3 × 10^(8))/(0.154 × 10^(-9))
E = 12.92 × 10^(-16) J
The energy associated with the photons of X rays with a wavelength of 0.154 nm is 1.29 × 10⁻¹⁵ J.
When copper is bombarded with high-energy electrons, X rays, with a wavelength of 0.154 nm (λ) are emitted.
We can calculate the energy (E) associated with the photons of these X rays using the Planck-Einstein relation.
[tex]E = \frac{h \times c }{\lambda } = \frac{(6.63 \times 10^{-34}J.s ) \times (3.00 \times 10^{8}m/s ) }{0.154 \times 10^{-9} m } ]= 1.29 \times 10^{-15} J[/tex]
where,
h: Planck's constantc: speed of lightThe energy associated with the photons of X rays with a wavelength of 0.154 nm is 1.29 × 10⁻¹⁵ J.
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HELP QUICK What is the mass of an object that has a volume of 2 ml and a density of 10g/ml?
Answer:
The answer is 20 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question we have
mass = 10 × 2
We have the final answer as
20 gHope this helps you
hello nice ppl(ɔ◔‿◔)ɔ ♥
Answer:
Hi
Explanation:
How has your brainly experience been so far? Are you liking?
Answer:
Thx you are sooo noice
Explanation:
UwU U3U
A trucker is driving from New Jersey to California to make a delivery of couches. He forgets to adjust the pressure of his tires before his trip and end up blowing out two of his tires while driving through Arizona. Whose law does this example depict? What does this law state? Use the law to explain what happened to the tires.
Answer:
Gay-Lussac's law.
Explanation:
According to Gay-Lussac's pressure law, it states that the pressure of a given mass of gas is directly proportional to the absolute temperature of the gas, the assumption that the volume is kept constant.
Hence, the trucker's tires were blown up because they were under high pressure as he drove from New Jersey to California, as a result of this intense pressure the temperature of the air in the tires began to rise and it directly affected the pressure of the gas in the tires' tubes which also increased to a point that they ended up blowing out, obeying Gay-Lussac's law.
For lunch you have a glass of sweetened ice tea. The glass contains crushed tea leaves, sugar, a slice of lemon, and both liquid and frozen water (ice cubes). Which of the following categories of matter best describes the contents of the glass? *
Answer:
I think solids
Explanation:
sorry if its not right
One of the uses of methanol (CH3OH) in dilute form is as a windshield washer antifreeze. In pure form, methanol has a molar concentration of 24.7M. How many moles are contained in 500 mL of solution?
Mole itself is the number of particles contained in a substance
1 mole = 6.02.10²³ particles
Mole : the ratio of the amount of substance mass and its molar mass
[tex]\large{\boxed{\boxed{\bold{mole=\frac{mass}{molar\:mass}}}}[/tex]
Molarity is a way to express the concentration of the solution
Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution
[tex]\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}[/tex]
Molar concentration of methanol=24.7 M
Volume of solution = 500 ml = 0.5 L
[tex]\tt mol=M\times V\\\\mol=24.7\times 0.5\\\\mol=12.35[/tex]
How is the nuclear structure of an atom similar to the non-nuclear structure?
Answer:
It has shells of protons and neutrons.
Explanation:
The nuclear structure of an atom is similar to the non-nuclear structure because has shells of protons and neutrons.
What is an atom?An atom consists of a central nucleus that is usually surrounded by one or more electrons.
The total number of neutrons plus protons in the same both before and after the nuclear process, although the total number of protons and the total number of neutrons may be different before and after.
Hence, the nuclear structure of an atom is similar to the non-nuclear structure because has shells of protons and neutrons.
Learn more about the atoms here:
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How many cesium atoms are in 21.9 grams?
What is the oxidation number of Gallium?
Answer: +3
Explanation: Gallium liquefies just above room temperature. Gallium is a soft solid, however it quickly becomes liquid when heated.
11. How many moles are in 7.14 X 10 35
molecules of 02?
Answer:
The answer is 1.186 × 10¹² molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question
N = 7.14 × 10^35 molecules of O2
We have
[tex]n = \frac{7.14 \times {10}^{35} }{6.02 \times {10}^{23} } \\ [/tex]
We have the final answer as
1.186 × 10¹² molesHope this helps you
A + ion (positive ion, one with extra positive charge)?
Answer:
If an ion has a positive charge then it has lost an electrons.
Explanation:
So you don't "gain" anything when the ion has a positive charge. It loses an electron which means it has more protons than electrons. Thus, the ion has a positive charge. If it "gained" an electron then it would have a negative charge.
In the apple activity you completed which of the following is an example of a constant
Answer: the type of apple because it is an example of a constant
Explanation:
Burning 1 kg of coal releases about 3 million joules of energy. If you could use all of the chemical energy to lift another kilogram of coal, how high could you lift it?
I could lift 3.06 x 10⁵ m high
Further explanationEnergy is the ability to do work. Energy can change from one energy to another
Potential energy is the energy that an object has because of its position
The potential energy can be formulated:
Ep = m. g. h
E = potential energy of an object, joule
m = object mass, kg
g = gravity acceleration, m / s²
h = height of an object, m
energy of coal = 3.10⁶ J
mass = 1 kg
g = 9.8 m/s²
[tex]\tt h=\dfrac{E}{m.g}\\\\h=\dfrac{3.10^6}{1\times 9.8}=3.06\times 10^5`m[/tex]
Analyzing a blood sample usually involves which type of separation method?
screening
distillation
centrifugation
filtration
Answer:
the answer is b
Explanation:
i just did quizz
Jakasia needed to find the volume of a plastic container in L to see if the 170 L of
solution that she had would fit inside. She knew that one side was 2.5 ft, the
height of the box was 60 cm, and width of the box was 0.8 m. Use dimensional
analysis to determine if Jakasia's solution will fit in the container.
Answer:
The solution will fit into the container.
Explanation:
The following data were obtained from the question'
Volume of solution = 170 L
Length of container (L) = 2.5 ft
Height of container (H) = 60 cm
Width of container (W) = 0.8 m
Volume of container (V) =?
Next, we shall express the length, height and breadth I the same unit of measurement. In this case, we shall all in centimetres (cm).
For the length:
1 ft = 30.48 cm
Therefore,
2.5 ft = 2.5 ft × 30.48 cm / 1 ft
2.5 ft = 76.2 cm
Thus the length is 76.2 cm
For the width:
1 m = 100 cm
Therefore,
0.8 m = 0.8 m × 100 cm / 1 m
0.8 m = 80 cm
Thus, the width of the container is 80 cm.
Next, we shall determine the volume of the container as follow:
ength of container (L) = 76. 2 cm
Height of container (H) = 60 cm
Width of container (W) = 80 cm
Volume of container (V) =?
Volume = length × width × height
Volume = 76.2 × 80 × 60
Volume = 365760 cm³
Finally, we shall convert 365760 cm³ to litre (L). This can be obtained as follow:
1000 cm³ = 1 L
Therefore,
365760 cm³ = 365760 cm³ × 1 L/ 1000 cm³
365760 cm³ = 365.76 L
Therefore, the volume of the container is 365.76 L
Since the volume of the container (i.e 365.76 L) is bigger than the volume of the solution (i.e 170 L), therefore, the solution will fit into the container.
Is this correct?
If the temperature is below the melting point the substance is a solid
If the temperature is above the boiling point the substance is a gas
If the temperature is in between the boiling and melting points the substances a liquid.
If the normal melting point of a substance is below room temperature, the substance is a liquid at room temperature.
If both the normal melting point and the normal boiling point are above room temperature, the substance is a solid.
Which of the following is the least likely to remain homogeneous?
. O A. All of these
O B. A supersaturated solution
O C. An unsaturated solution
O D. A saturated solution
Answer:
all
of them
Explanation:
(True or False) Only an odd number of orbitals is possible for any electron sublevel?
Answer:
The statement is true
I found this doing research.
Apparantly, each sub level is made up of one or more orbitals and the orbitals in each sub level are always odd number. Each orbital can only have two electrons and those two electrons will have opposite spin.
Explanation:
Answer:
True
Explanation:
what does MA 2 means?
Answer:
Master-at-Arms Petty Officer 2nd Class. MA2. Machine Accountant Second Class (Naval Rating) Copyright 1988-2018 AcronymFinder.com, All rights reserved.
Explanation:
Line M passes through the points (-5, 9) and (-1,9).
12
10-
8
6
2
-12-10-8-6-4-22
2
6 8 10 12 X
6
-10
-12-
Which is true of line M?
Answer:
line m is vertical line with an undefined slopel line correct answer is 6 8 10 12 x
Ben makes five paper helicopters with different wing lengths. He drops them the same way from a height of two meters for five trials each. He records the amount of time it takes for each helicopter to fall to the ground. What is the independent variable?
Answer:
Wing length
Explanation:
According to the given excerpt, independent variable is 'wing length' and dependent variable is 'amount of time it takes for helicopter to hit the floor'.
Independent variable refers to the variable that do not undergo any change or shift in the course of the experiment of research. The other variables are measured using the constant independent variable. The value obtained from the independent variable is independent. On the other and, the dependent variable witnesses change with respect to the independent variable.
How much heat is required to melt 42.0 grams of water at 0*C?
Hurry...
Answer:
Heat required to melt 42 g if ice is 13,860 J
Explanation:
The amount of heat required to melt grams of water at 0°C is given as follows;
The mass of the ice (water), m = 42 g
The latent heat of fusion of ice Δ[tex]H_f[/tex]= 330 J/g
Therefore, heat required to melt 42 grams is given as follows;
Heat required to melt ice = Mass of the ice, m × The specific latent heat of fusion of the ice, Δ[tex]H_f[/tex]
Heat required to melt 42 g if ice = m × Δ[tex]H_f[/tex] = 42 g × 330 J/g = 13,860 J
Heat required to melt 42 g if ice = 13,860 J.
As part of a chemistry experiment, Sam notes that the temperature at which liquid mercury
freezes into a solid is -102 Fahrenheit (F). The beaker of liquid mercury provided to him Is
at a room temperature of 68". By how many degrees will Sam have to cool the liquid
mercury for it to freeze into a solid?
-102"F
-34°F
102°F
170°F
o
Answer:
-34¨F
Explanation:
The number of shovels and cost per 1000 kg for
Ca(OH)2
Answer:500
Explanation:
Does changing the number of neutrons affect the atomic number?
Answer:
awsdxcvawsd
Explanation:
Answer:If you change the number of neutrons in an atom, you get an isotope of the same element. The addition of a neutron can make an atom radioactive. When you change the number of protons in an atom, you will change the atom from one element to a different element.
Explanation:
Please help me with this I’ve been on this question for 10 minutes now...
Answer:
A
Explanation:
we know that pangea was when all the continents were connected and the tectonic plates moved, causing pangea to split into multiple pieces. so north america was formed by moving tectonic plates.
i hope this helps :))
NEEEDDDD HELP ASAP PLZ PLZ PLZ PLZ PLZ HELP ME
Answer:
[tex]ns^2[/tex]
Explanation: