Answer:
The periodic law states “When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties
How many protons, neutrons, and electrons does Sr^2+
Answer:
36 electrons
Explanation:
The # of protons is always equal to the atomic number. In the case of Sr (Strontium), it is 38 protons.
The 2+ at the end means that it has a charge of +2, meaning that it LOST two electrons to become a cation with a full valence shell. So, 38 - 2 = 36 electrons
Answer:
38 protons 36 electrons 30 neutron because of 29 isotope
A piece of string is found to be 35.9 meters long how long is the string in inches?
Answer:
1413.386
Explanation:
which element can form an oxide with the general formula m2o or mo where m is a metal
Answer:
Because the compound has a formula of M2O, the number of valence electrons of M should be 1. Therefore, (1) Group 1 is the correct answer because elements in group 1 have 1 valence electron.
Explanation:
curicun, named for marie curie, has approximately 25 different isotopes that emit an alpha particle when their nuclei decay. if curium-247, the most abundant nuclide, emit and alpha particle, what daughter nuclide is formed?
A. Californium-251
B. Plutonium-243
C. Californium-249
D. Plutonium-251
Answer:
Option B. Plutonium-243
Explanation:
To know the the correct answer to the question, we shall write the balanced equation for the reaction showing curium-247 (²⁴⁷Cm) emitting alpha particle. This is illustrated below:
²⁴⁷₉₆Cm —> ᵐₙX + ⁴₂He
Next, we shall determine m, n and X. This can be obtained as follow:
247 = m + 4
Collect like terms
247 – 4 = m
243 = m
Thus, m is 243
96 = n + 2
Collect like terms
96 – 2 = n
94 = n
Thus, n is 94
m = 243
n = 94
ᵐₙX => ²⁴³₉₄X => ²⁴³₉₄Pu
Thus, the equation is:
²⁴⁷₉₆Cm —> ²⁴³₉₄Pu + ⁴₂He
From the illustrations above, the daughter nuclei formed is Plutonium-243 (²⁴³₉₄Pu)
Answer:
Plutonium-243
Explanation:
Why do gases spread throughout the air, but liquids or solids stay together?
Answer:
In gases are much more spread out than in solids or liquids. They vibrate and move freely at high speeds. A gas will fill any container, but if the container is not sealed, the gas will escape. Gas can be compressed much more easily than a liquid or solid.
Explanation:
(5) Use scientific notation, make the following conversions:
6.20 km to m
Answer:
6200 meters
Explanation:
To convert from km to m you have to multiply the number by a thousand
Answer:
6.2×10^3 m
Explanation:
6.20×1000=6200m
In scientific notation 6200 = 6.2×10^3
12-How many elements are in the mixture pictured below?
A-7
O B-4
C-3
D-2
In the image shown above, there are 3 elements (option C).
What is an element?Element is one of the simplest chemical substances that cannot be decomposed in a chemical reaction or by any chemical means and made up of atoms all having the same number of protons.
As stated above, all elements are made up of backbone structures called atoms. The atoms of an element are the same.
According to this question, an image is given showing atoms of different colors. Each atom with the same color belongs to a single element.
Since there are there colors, this means that there are three elements in the picture.
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(I will give a brainliest) What must be changed, temperature or heat during condensation?
Answer: Temperature
Explanation:
Answer: Temperature
Explanation: can i get brainliest plss
A compound is found to contain 64.80 % carbon, 13.62 % hydrogen, and 21.58 % oxygen by weight. To answer the questions, enter the elements in the order presented above. 1. What is the empirical formula for this compound
Answer:
[tex]C_{4}H_{10}O[/tex]
Explanation:
Hello!
In this case, since the empirical formula of compounds whose by-mass compositions are known, is computed by first computing the moles considering those compositions as actual masses:
[tex]n_C=\frac{64.82g}{12.01g/mol}=5.40mol\\\\n_H=\frac{13.62g}{1.01g/mol}=13.5mol\\\\n_O=\frac{21.58g}{16g/mol}=1.35mol[/tex]
Next, we divide each moles by the fewest ones, in this case those of oxygen to obtain the subscript in the empirical formula:
[tex]C=\frac{5.40}{1.35}= 4\\\\H=\frac{13.5}{1.35}=10\\\\O=\frac{1.35}{1.35}=1[/tex]
Thus, we obtain:
[tex]C_{4}H_{10}O[/tex]
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If 10.88 moles of NH3 were produced, how many moles of N2 would be
required?
Answer:
5.44 moles of nitrogen required.
Explanation:
Given data:
Number of moles of NH₃ = 10.88 mol
Moles of N₂ required = ?
Solution:
Chemical equation:
N₂ + 3H₂ → 2NH₃
Now we will compare the moles nitrogen and hydrogen.
NH₃ : N₂
2 : 1
10.88 : 1/2×10.88 = 5.44mol
5.44 moles of nitrogen required.
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Answer:
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A compound is found to contain 2.270 % hydrogen, 34.80 % phosphorus, and 62.93 % oxygen by mass. What is the empirical formula for this compound
Answer: The empirical formula is [tex]H_4P_2O_7[/tex]
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of H= 2.270 g
Mass of P = 34.80 g
Mass of O = 62.93 g
Step 1 : convert given masses into moles
Moles of H = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{2.270g}{1g/mol}=2.270[/tex]
Moles of P = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{34.80g}{31g/mol}=1.122[/tex]
Moles of O = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{62.93g}{16g/mol}=3.933[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For H = [tex]\frac{2.270}{1.122}=2[/tex]
For P= [tex]\frac{1.122}{1.122}=1[/tex]
For O = [tex]\frac{3.933}{1.122}=3.5[/tex]
The simples ratio will be = H: P : O= 4: 2: 7
Hence the empirical formula is [tex]H_4P_2O_7[/tex]
at the molecular level what form of energy do the molecules have?
Answer:
kinetic energy I think so
The form of energy molecules have at the molecular level is Kinetic energy.
Kinetic energy is defined as the energy possessed by a body as a result of its motion or movement.
Molecules interact with one another through various movements that occur
within them. This happens to aid the formation of new substances in the
ecosystem. The three states of matter exhibit varying degree of movement
within its molecules.
The energy is usually in the form of chemical energy also and is the reason
why kinetic energy is the most suitable choice.
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What is Darwin's name for species that do not appear to have changed for millions of years?
Since, the options have not been given the question is incomplete.
What is Darwin's name for species that do not appear to have changed for millions of years?
a.
Dinosaurs
b.
Living fossils
c.
Old souls
d.
Ancient moderns
Answer: b. Living fossil
Explanation:
In 1859 Charles Darwin proposed the term living fossil, that means a species or group of species that had not changed in terms of evolutionary context thus can be useful in tracing the extinct or previously existing forms of life. The examples of the living fossils are horseshoe crabs, ginkgo (Conifers) and tuatara. These group of animals were existed unchanged in the Ordovician, Permian, and Triassic periods respectively with few surviving species.
Answer:
the answer is living fossils so it would be b
Explanation:
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11-Which of the following would NOT be a Compound?
A?
B?
C?
D?
Answer:
A because it is not small enough
Explanation:
It's a of c Yea a or so pick that
How many molecules of N2O4 are in 76.3g N2O4? The molar mass of N2O4 is 92.02 g/mol.
a. 4.59 × 10^25 N2O4 molecules
b. 5.54 × 10^25 N2O4 molecules
c. 7.26 × 10^23 N2O4 molecules
d. 1.38 × 10^24 N2O4 molecules
e. 4.99 × 10^23 N2O4 molecules
Answer:
4.99*10²³ molecules of N₂O₄ are in 76.3 g of N₂O₄
Explanation:
Avogadro's Number is the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole. Avogadro's number represents a quantity without an associated physical dimension. Avogadro's number applies to any substance.
You know that the molar mass of N₂O₄ is 92.02 g/mol, and you have 76.3 g. Then you can apply the following rule of three: 92.02 grams are present in 1 mole of the compound, 76.3 grams in how many moles are they?
[tex]amount of moles= \frac{76.3 grams*1 mole}{92.02 grams}[/tex]
amount of moles= 0.83 moles
Then, you can apply another rule of three: if by definition of Avogadro's number 1 mole of the compound has 6.023*10²³ molecules, 0.83 moles of the compound, how many molecules will it have?
[tex]amount of molecules= \frac{0.83 moles*6.023*10^{23}molecules }{1 mole}[/tex]
amount of molecules= 4.99*10²³
4.99*10²³ molecules of N₂O₄ are in 76.3 g of N₂O₄
Adding oil to a table would ___________ the friction when sliding a book across it.
Increase or decrease
Answer:
Increase
Explanation:
Hope it helps you
Answer:
Decrease
Explanation:
If the oil you're referring to is just some normal oil, it'll lessen the friction and cause it to side more smoothly
How are molecules built?
All of these
Phase Changes
Atomic Rays
Bonding
1
Answer:
By bonding due to the attractive forces
Measurements show that unknown compound X has the following composition: element mass % chromium 68.4% oxygen 31.5% Write the empirical chemical formula of X.
Answer: The empirical formula of X is [tex]Cr_2O_3[/tex]
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of Cr = 68.4 g
Mass of O = 31.5 g
Step 1 : convert given masses into moles.
Moles of Cr =[tex]\frac{\text{ given mass of Cr}}{\text{ molar mass of Cr}}= \frac{68.4g}{52g/mole}=1.31moles[/tex]
Moles of O =[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{31.5g}{16g/mole}=1.97moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Cr = [tex]\frac{1.31}{1.31}=1[/tex]
For O = [tex]\frac{1.97}{1.31}=1.5[/tex]
The simple whole number ratio of Cr : O= 2: 3
Hence the empirical formula is [tex]Cr_2O_3[/tex]
How many pounds of gold ore would need to be processed to obtain 5 grams of gold (Au) if the ore is 0.1% gold by mass?
Pounds of gold ore : 11,02311
Further explanationGiven
5 g of gold
0.1% gold by mass
Required
Pounds of gold ore
Solution
[tex]\tt \%mass~gold=\dfrac{mass~gold}{mass~ore}\times 100\%[/tex]
For percent mass = 0.1%, than mass of gold ore :
[tex]\tt 0.1\%=\dfrac{5~g}{mass~ore}\times 100\%\\\\mass~ore=\dfrac{5\times 100}{0.1}\\\\mass~ore=5000~g[/tex]
Conversion factor :
1 g = 0,00220462 pound, than for 5000 g = 11,02311 pounds
Did kinetic energy increase or decrease in each tank? Why
Answer:
I hope this helps!Good luck
Why milk sours is chemical change ?
Answer:
Explanation:
So chemical changes require a change on a molecular level that cannot be reversed because they form some new substance. Souring milk is not something you can reverse, and the process of it souring produces new molecules.
When iron is combined with copper (1) nitrate, it produces iron (II) nitrate and
copper. Which of the following could NOT be a mole ratio in this chemical
reaction?
A)1 mole Fe / 2 mole Cu
B)1 mole Fe(NO3)2 / 2 mole Cu
C)2 mole Cu(NO3)2 / 2 mole Fe
D)1 mole Fe(NO3)2 / 1 mole Fe
Answer:
C)2 mole Cu(NO3)2 / 2 mole Fe
Explanation:
I'm pretty sure.
When iron is combined with copper (1) nitrate, it produces iron (II) nitrate and copper. The following could NOT be a mole ratio in this chemical reaction is:
D) 1 mole Fe(NO₃)₂ / 1 mole Fe
To determine which of the given mole ratios could NOT be part of the chemical reaction between iron and copper(1) nitrate, we need to write the balanced chemical equation for the reaction and then compare it to the given ratios.
The balanced chemical equation for the reaction is:
Fe + Cu(NO₃)₂ → Fe(NO₃)₂ + Cu
A) 1 mole Fe / 2 mole Cu
This mole ratio is consistent with the balanced chemical equation, where 1 mole of Fe reacts with 2 moles of Cu(NO₃)₂ to produce 1 mole of Fe(NO₃)₂ and 1 mole of Cu. So, this ratio could be part of the chemical reaction.
B) 1 mole Fe(NO₃)₂ / 2 mole Cu
This mole ratio is also consistent with the balanced chemical equation, where 1 mole of Fe(NO₃)₂ is produced by reacting 2 moles of Cu(NO₃)₂. So, this ratio could be part of the chemical reaction.
C) 2 mole Cu(NO₃)₂ / 2 mole Fe
This mole ratio is consistent with the balanced chemical equation, where 2 moles of Cu(NO₃)₂ react to produce 2 moles of Fe(NO₃)₂. So, this ratio could be part of the chemical reaction.
D) 1 mole Fe(NO₃)₂ / 1 mole Fe
This mole ratio implies that 1 mole of Fe(NO₃)₂ is produced by reacting with 1 mole of Fe, which is not consistent with the balanced chemical equation. The equation shows that 1 mole of Fe reacts with 1 mole of Cu(NO₃)₂ to produce 1 mole of Fe(NO₃)₂ and 1 mole of Cu. Therefore, this ratio could NOT be part of the chemical reaction.
So, the correct answer is:
D) 1 mole Fe(NO₃)₂ / 1 mole Fe
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The weight of an object is different on each planet because
O mass changes with location
O each planet has a different force of gravity
O each planet is a different distance from the sun
Omass of the object changes on each planet
Answer:
each planet has a different force of gravity
Explanation:
Weight = mass× gravity
As gravity changes from place to place and also from planet to planet so weight changes.
A tire is inflated physical or chemical ?
Answer: physically
Explanation: it's a physical change because the air that fills it up does not affect its chemical compound like I'd you mix metal in salt water
if Fe(NO3)3 is dissolved in enough water to make exactly 323 ml of solution, what is the molar concentartion of nitrate ion g
The given question is incomplete. the complete question is : If 5.15 g[tex]Fe(NO_3)_3[/tex] is dissolved in enough water to make exactly 323 ml of solution, what is the molar concentartion of nitrate ion.
Answer: The molar concentartion of nitrate ion is 0.195.
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
Given : 5.15 g of [tex]Fe(NO_3)_3[/tex] is dissolved
Volume of solution = 323 ml
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n= moles of solute
[tex]Moles=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{5.15g}{242g/mol}=0.021moles[/tex]
[tex]V_s[/tex] = volume of solution = 323 ml
[tex]Molarity=\frac{0.021\times 1000}{323}=0.065M[/tex]
As 1 M of [tex]Fe(NO_3)_3[/tex] gives 3 M of [tex]NO_3^-[/tex] ions.
Thus 0.065 M of [tex]Fe(NO_3)_3[/tex] gives = [tex]\frac{3}{1}\times 0.065=0.195M[/tex] of [tex]NO_3^-[/tex] ions.
The molar concentartion of nitrate ion is 0.195.
What is a molecule contains the genetic instructions for the development and functioning of all living organisms found in the nucleus of a cell
And electro chemical cell has the following standard cell notation:
Mg(s) | Mg2+ (aq) || Ag+(aq)| Ag(s)
Write a balanced redox reaction for the cells using the oxidation and reduction half reactions. (be sure to equalize charge by multiplying the correct number before adding and simplifying)
2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)
Further explanationGiven
Standard cell notation:
Mg(s) | Mg2+ (aq) || Ag+(aq)| Ag(s)
Required
a balanced redox reaction
Solution
At the cathode the reduction reaction occurs, the anode oxidation reaction occurs
In reaction:
Ag⁺ + Mg → Ag + Mg²⁺
half-reactions
at the cathode (reduction reaction)Ag⁺ (aq) + e⁻ ---> Ag (s) x2
2Ag⁺ (aq) + 2e⁻ ---> 2Ag (s)
at the anode (oxidation reaction)Mg (s) → Mg²⁺ (aq) + 2e−
a balanced cell reaction
2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)
Answer:2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)
Explanation:
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How can both the pitcher and the glass contain the same volume of iced
tea?
Answer: $6,600[tex]\alpha \sqrt[n]{x} \lim_{n \to \infty} a_n[/tex]
Explanation: