Answer:
A = 55
Explanation:
The atomic number is the number of protons also = the number of electrons, so basically we have 29 neutrons, 26 electrons and 26 protons. Anyway, it's asking the mass number which is the neutrons + the protons, so you just take 29+26 = 55
Atomic number=26
Neutrons=29
Electrons=26
Mass number=Proton+neutron
Protons=26
Mass number=26+29
=55
What is the percent, by mass, of water in MgSO4.2H20
Answer:51.1%
Explanation:
Mass percent : It is defined as the mass of the given component present in the total mass of the compound. Formula used : First we have to calculate the mass of and . Mass of = 18 g/mole Mass of = 7 × 18 g/mole = 126 g/mole Mass of = 246.47 g/mole Now put all the given values in the above formula, we get the mass percent of in . Therefore, the mass percent of in is, 51.1%
5 grams of sodium bicarbonate, a white powdery solid, is placed in an empty red balloon. 100 grams of acetic acid, a clear aqueous solution, is placed in the plastic bottle. The balloon is carefully attached to the bottle so that no air can get in or out and the powder does not fall into the bottle. Once attached, the apparatus is placed on a balance and the contents are mixed. Bubbles form, the balloon inflated, and the white powder is no longer visible. Which of the these statements would match your observations? A) A chemical reaction has occurred and the mass will increase. B) A chemical reaction has occurred and the mass will decrease. C) A physical reaction has occurred and the mass will decrease. D) A chemical reaction has occurred and the mass will remain the same.
Answer: im pretty sure its D
Explanation:
How long is a sunflower seed? Select the best estimate.
15 meters
15 kilometers
15 millilmeters
15 centimeters
Answer:
15 millimeters
Explanation:
the other answer choices are too large.
Answer:
15 millimeters
Explanation:
The other options are too long.
PLEASE HELP ASAP I'M SO STRESSED
Answer:
160.3g
Explanation:
We know the equation:
No of moles = mass ÷ Mass of element
We need to find the mass, so make mass the subject of the formula.
Mass = No. of moles × mass of element
Mass = 5 × 32.06
Mass = 160.3g
the atomic number of four elements p,q,r,s are 6,8,10 and 12 respectively. the two elements which can bond ionically are:
Answer:
The atomic numbers of four elements A, B, C, and D are 6,8,10, and 12 respectively. The two elements which can react to form ionic bonds (or ionic compounds) are B (8= 2,6) and D (12 =2,8,2). So D donates its two electrons to B to fulfill their octet.
Explanation:
What happens to the atoms in a chemical reaction? Explain with an example
2 WHAT ARE THE THREE THINGS NECESSARY TO MAINTAIN A FIRE?
Answer:
Oxygen, heat, and fuel
Explanation:
Oxygen, heat, and fuel are frequently referred to as the "fire triangle." Add in the fourth element, the chemical reaction, and you actually have a fire "tetrahedron." The important thing to remember is: take any of these four things away, and you will not have a fire or the fire will be extinguished.
100 POINTS PLEASE HELP
1. What is the molar mass of NaOH?
2.How many atoms are in 3.35 moles of Aluminum?
3.How many moles of CO2 gas are in a 101.25 L container filled with CO2 gas?
4.What is the mass of 13.7 moles of N2 gas?
5.How many moles are in 78.5 molecules of CaCO3?
Answer:
1. 39.997 g/mol
2. 6.022⋅1023 atoms of aluminium
3. 0.026 moles
4. 14 grams is the molar mass of nitrogen meaning that one mole of nitrogen atoms is 14 grams. One mole of any substance has 6.02*10^23 atoms/molecules of that subtance therefore there are 6.02*10^23 atoms of nitrogen in 14g of nitrogen
5. 78.5
Explanation:
The main-group elements are the forty-four elements that occupy groups 1A-8A of the periodic table. Main-group elements are important because of their high natural abundance both in the Earth's crust and in the human body and are commercially valuable. Review the families containing main group elements. Identify all the characteristics that apply to the elements in family IA.
Answer:
The answer is a,b, and c. This is for the USA tesprep videos
Explanation:
The characteristics that apply to the elements in the family are they are highly reactive, they are shiny, soft metals and the element form +1 ions when forming compounds. Thus option a, b and c is correct.
What are main group elements?Main group elements are defined as any of the element belonging to the s and p blocks of the periodic table.
They are most abundant element in universe and on earth.
This elements and their compound are one of the most important economical elements.
They are very good conductor of heat and electricity.
Thus, the characteristics that apply to the elements in the family are they are highly reactive, they are shiny, soft metals and the element form +1 ions when forming compounds. Thus option a, b and c is correct.
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What does the electron configuration for the noble gases tell us about the elements in the
group
Answer:That all noble gases will have 8 valence electrons which makes a atom stable
Explanation:
how many moles are in 8.32 × × times 10^24 molecules of co2?
Answer:
13.8 moles
Explanation:
You know that in a mole you have 6.022x10²³ something in this case of molecules. By knowing that by each mole you have 6.022x10²³ molecules, then you can establish the factor of conversion:
8.32x10²⁴molec of CO2 x 1 mol/6.022x10²³ molec of CO2
You divide 8.32x10²⁴/6.022x10²³ and you get 13.81 moles.
I need help!!!!!!!!!!!!!!!
Answer:
I think the answer is A.
Explanation:
hope this helps.
The work you do on a machine is called the_________________
Answer:
THE WORK YOU DO ON A MACHINE IS CALLED WORK INPUT
A sample of a certain gas has a volume of 452 mL at 711 mmHg and 26 degrees C. What would be the volume of this same sample of gas if it were measured at STP
The volume of this same sample of gas if it were measured at STP is 386.09mL
HOW TO CALCULATE VOLUME:
The new volume of a gas sample can be calculated using the following expression:
P1V1/T1 = P2V2/T2
Where;
P1 = initial pressureP2 = final pressureV1 = initial volumeV2 = final volumeT1 = initial temperatureT2 = final temperatureAccording to this question, a sample of a certain gas has a volume of 452 mL at 711 mmHg and 26°C (299K).
(711 × 452)/299 = 760 × V2/273
1074.82 = 2.78V2
V2 = 1074.82 ÷ 2.78
V2 = 386.09mL
Therefore, the volume of this same sample of gas if it were measured at STP is 386.09mL.
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Which subatomic particles have a positive charge and are located in the nucleus?
a. neutrons
b. atoms
c. electrons
d. protons
Answer: protons
Explanation:
a) Neutrons are located in the nucleus but have a negative charge.
b) Atoms are not subatomic particles but are rather made of subatomic particles.
c) Electrons are subatomic particles with a negative charge that are located outside of the nucleus.
d) Protons are subatomic particles that are located in the nucleus and have a positive charge.
Of the following elements, which one has the smallest first ionization energy?
A. boron
B. carbon
C. aluminum
D. silicon
Answer:
C. Aluminum
Explanation:
Aluminum has 5.9858 ionization energy
Boron has 8.298 ionization energy
Silicon has 8.1517 ionization energy
Carbon has 11.2603 ionization energy
1. Which of the following statements about the properties of elements related to an
atomic emission spectrum are true? Select all that apply. (3 are correct)
The emission spectrum of an atom consists of limited lines that are unique to a given element.
According to the Bohr model of the atom, energy is absorbed or emitted when an atom moves from one energy level to another. Since energy is quantized, the spectrum of atoms often consists of single lines.
Hence, the true statement about atomic spectrum is that; "the light that an element emits is made up of a limited number of narrow lines that produce a unique pattern or atomic emissions spectrum for that element."
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What halogen can react with sodium chloride solution to produce chlorine?
Answer:
As electro-negativity decreases from Florine to downwards in the group and only Florine is above Chlorine, so Florine should react with sodium chloride solution to produce chlorine.
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how does ionization energy increase on the periodic table
[tex]\huge \bf༆ Answer ༄[/tex]
The trends showing increase in ionization energy on the periodic table ~
Ionization energy increases as we move from left to right in a period.[ due to increase in effective nuclear charge ]
Ionization energy increases as we move from bottom to top in a group.[ Due to decrease in number of shells ]
Ionization energy increases across a period from left to right in the periodic table.
Ionization energyIonization energy is the energy needed for the complete removal of valence electrons in its ground state from an isolated atom in its gaseous phase at a specified temperature to form an ion.
Ionization energy shows periodicity in that it shows a regular variation across a period and down a group in the periodic table.
Ionization energy increases across a period from left to right in the periodic table.
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How many molecules are present in a sample that is 89 g of H2O?
[tex]\qquad[/tex][tex] \pink{\bf\longrightarrow { Molar \:mass \:of \:H₂O:-} }[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow 1\times +16[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow 18g[/tex]
[tex]\qquad[/tex]____________________
Let's calculate the number of moles present in 89g of H₂O.
[tex]\qquad[/tex][tex] \purple{\bf\longrightarrow { No \:of \:moles = \dfrac{Given \:mass}{Molar\: mass}}}[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow \dfrac{89}{18}[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow 4.94\: moles[/tex]
We know –
Avogadro number = 6.022×10²³Number of molecules:-
[tex]\qquad[/tex][tex] \purple{\bf \longrightarrow No \: of \: moles \times Avogadro \: number}[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow 4.94×6.022×10²³[/tex]
[tex]\qquad[/tex][tex] \sf \longrightarrow 2.98 ×10²⁴[/tex]
[tex]\qquad[/tex][tex]\purple{ \bf \longrightarrow 2.98×10²⁴ molecules}[/tex]
Thus, 2.98×10²⁴ molecules are there in 89g of H₂O.[tex]\qquad[/tex]____________________
Explain why some substances travel further than others.
Larger molecules take longer to move up the chromatography paper or TLC plate, whereas smaller molecules are more mobile. Likewise, the polarity of the molecules can affect how far the spots travel, depending on the type of solvent used.
[tex]\large\sf\red{♡♡}[/tex]
Michael was sitting at his desk one morning. He noticed a small spot of light on the wall
which moved with his arm. What could be causing this spot of light on the wall?
O a) light from the window being refracted
by his watch band
b) light from the window reflecting off the
face of his watch
O c) light from the window being absorbed
by the wall
d) light from his watch refracting on the
wall
Answer:
Light from the window reflecting off the face of his watch <33
What is meant by collision theory?
Answer:
The collision theory states that a chemical reaction can only occur between particles when they collide (hit each other).
hope it helps~
Which of these substances are greenhouse gases? Check all that apply. Oxygen carbon dioxide helium methane nitrous oxide.
The greenhouse gases are carbon dioxide, methane, and nitrous oxide.
The greenhouse effect has been defined as the entrapment of the sun's energy by the gases that result in the earth becoming warmer and a better place to live.
The gases present in the atmosphere that has been able to entrap the heat energy has been termed the greenhouse gases.
The greenhouse gases have been carbon dioxide, methane, and nitrous oxide.
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Answer:
carbon dioxide, nitrous oxide, methane
Explanation:
If the velocity of a wave is 12 m/s and its frequency is 600 hertz, what would be its wavelength?
Answer:
The wavelength is 0.02 m.
Step-by-step explanation:
Given :
[tex]\green\star[/tex] Velocity = 12 m/s[tex]\green\star[/tex] Frequency = 600 HzTo Find :
[tex]\green\star[/tex] WavelengthUsing Formula :
Apply Wavelength formula :
[tex]\star{\small{\underline{\boxed{\sf{\purple{\lambda = \dfrac{v}{f}}}}}}}[/tex]
[tex]\pink\star[/tex] λ = Wavelength [tex]\pink\star[/tex] v = Velocity [tex]\pink\star[/tex] f = FrequencySolution :
Finding the wavelength by substituting the values in the formula :
[tex]{\longrightarrow{\sf{\lambda = \dfrac{v}{f}}}}[/tex]
[tex]{\longrightarrow{\sf{\lambda = \dfrac{12}{600}}}}[/tex]
[tex]{\longrightarrow{\sf{\lambda = \dfrac{\cancel{12}}{\cancel{600}}}}}[/tex]
[tex]{\longrightarrow{\sf{\lambda = \dfrac{2}{100}}}}[/tex]
[tex]{\longrightarrow{\sf{\lambda = \cancel{\dfrac{2}{100}}}}}[/tex]
[tex]{\longrightarrow{\sf{\lambda = 0.02}}}[/tex]
[tex]\star{\underline{\boxed{\tt{\red{\lambda = 0.02 \: m}}}}}[/tex]
Hence, the wavelength is 0.02 m.
Which of these would describe a dish that contains bits of chocolate and nuts you can see?
homogeneous mixture
compound
heterogeneous mixture
none of the above
Answer:
mezcla homogénea
Answer:
heterogeneous mixture
Explanation:
you can split the mixture easily with you hands while homogeneous mixtures is dissolved
Consider the reaction below. H2PO4â€"" H2O Right arrow. H3O HPO42â€"" Which of the following is a baseâ€""conjugate acid pair? H2O and H3O H2O and H2PO4â€"" H2PO4â€"" and HPO42â€"" H2PO4â€"" and H3O.
Taking into account the Brønsted-Lowry acid-base theory, a base/conjugate acid pair is H₂O/H₃O⁺.
The Brønsted-Lowry acid-base theory (or the Brønsted-Lowry theory) identifies acids and bases based on whether the species accepts or donates protons or H⁺.
According to this theory, acids are proton donors while bases are proton acceptors. That is, an acid is a species that donates an H⁺ proton while a base is a chemical species that accepts an H⁺ proton from the acid.
So, reactions between acids and bases are H⁺ proton transfer reactions, causing the acid to form its conjugate base and the base to form its conjugated acid by exchanging a proton.
In other words, a conjugate base is an ion or molecule resulting from the acid that loses the proton, while a conjugate acid is an ion or molecule resulting from the base that gains the proton:
acid + base ⇄ conjugate base + conjugate acid
In this case, you know:
H₂PO₄ + H₂O → H₃O⁺ + HPO₄⁻
H₂PO₄ behaves like acid because donates an H⁺ proton while H₂O behaves like base because accepts an H⁺ proton from the acid.
So, H₃O⁺ is the conjugate acid of the H₂O and HPO₄⁻ is conjugate base of H₂PO₄.
In summary, a base/conjugate acid pair is H₂O/H₃O⁺.
Learn more about the Brønsted-Lowry acid-base theory:
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To keep burning, fires require oxygen. Carbon dioxide is used in certain fire extinguishers to put out flames. Explanation: Because magnesium is higher on the reactivity scale than carbon, it is more reactive and eliminates oxygen from carbon dioxide (to give carbon and magnesium oxide).
What are some examples of a chemical change? (list more than 2 examples)
Cooking any food.
Burning of wood.
Digestion of food.
Acid-base reaction.
Andrea is making a solution of sweet tea, with 20 grams of sugar dissolved in 180
grams of water. Determine the mass percentage of sugar in the sweet tea.
The mass percentage of sugar in the sweet tea is 10%
From the question,
We are to determine the mass percentage of sugar in the sweet tea
[tex]Mass\ percentage\ of\ sugar\ in\ the\ sweet\ tea = \frac{Mass\ of\ sugar\ in\ the\ solution}{Mass\ of\ the\ solution} \times 100\%[/tex]
Mass of sugar in the solution = 20 g
Mass of the solution = 20g + 180g = 200g
[tex]Mass\ percentage\ of\ sugar\ in\ the\ sweet\ tea = \frac{20}{200} \times 100\%[/tex]
[tex]Mass\ percentage\ of\ sugar\ in\ the\ sweet\ tea = \frac{20}{2} \%[/tex]
∴ Mass percentage of sugar in the sweet tea = 10%
Hence, the mass percentage of sugar in the sweet tea is 10%
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