Phosphorus has an atomic mass of 31 and an atomic number of 15, so the number of neutrons must be _______________.
Answers
atomic mass= atomic number + number of neutrons
The atomic number (same thing as number of protons) in this case is 15. The atomic mass is 31.
So, we subtract 15 from 31 to find the number of neutrons.
31-15=16
16 neutrons!!!
sorry i'm late:
16 (how to get answer is shown below on second photo):
Related Questions
where are the most reactive nonmetals located on the periodic table?
a. the second column from the right side of the table
b. the uppermost complete row of the table
c. the column at the far left side of the table
d. the rows at the bottom of the table connecting two sections
Answers
The most reactive nonmetals are found in the column second from the right side of the periodic table, also known as Group 17 or the halogens. They are highly reactive because they need to gain just one electron to complete their outer electron shell. Fluorine is the most reactive nonmetal.
Explanation:The most reactive nonmetals are located in the upper right section of the periodic table, in the column that is second from the right side. This column is known as Group 17, or the halogens. Halogens are highly reactive due to their propensity to gain an electron to fill their outer electron shells, and they exhibit rich variety of chemical behaviors.
Elements belonging to the same column or group, such as the halogens, share many chemical characteristics because they have the same number of valence electrons.
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The half-life of a certain tranquilizer in the bloodstream is 5050 hours. how long will it take for the drug to decay to 8686% of the original dosage? use the exponential decay model, upper a equals upper a 0 e superscript kta=a0ekt, to solve.
Answers
We know that "A" is half of A0
A = A0 e^(k× 5050)
A/A0 = e^(5050k)
0.5 = e^(5055k)
In (0.5) = 5055k
-0.69315 = 5055k
k = -0.0001371
To calculate how long it will take to decay to 86% of the original mass
0.86 = e^(-0.0001371t)
In (0.86) = -0.0001371t
-0.150823 = -0.0001371 t
t = 1100 hours
What type of wave is sound?
a.longitudinal
b.surface
c.light
d.transverse
Answers
a.longitudinal.
If 2500. J of energy are added to 120. g of benzene at 30. degrees C, what will be its final temperature?
Answers
q = m Cp (T₂ - T₁) --- (1)
where;
Cp = Specific Heat
Specific heat of Benzene is 1.72 J/g.°C
Now,
Solving equation 1,
(T₂ - T₁) = q / m Cp
Putting values,
(T₂ - 30 °C) = 2500 J ÷ (120 g ×1.72 J/g.°C)
(T₂ - 30 °C) = 2500 J ÷ (206 J/°C)
(T₂ - 30 °C) = 12.13 °C
T₂ = 12.13 °C + 30 °C
T₂ = 42.13 °C
The final temperature of benzene after adding 2500 J of energy is 41.97°C.
To determine the final temperature of benzene after adding 2500 J of energy, we can use the formula for specific heat capacity:
q = mcΔT
Where:
q is the heat added (2500 J)m is the mass of benzene (120 g)c is the specific heat capacity of benzene (1.74 J/g°C)ΔT is the change in temperatureRearranging the formula to solve for ΔT:
ΔT = q / (mc)
Substitute the given values:
[tex]\Delta T = \frac{2500 \, \text{J}}{120 \, \text{g} \times 1.74 \, \text{J/g \textdegree C}}\\\\\Delta T = \frac{2500 \, \text{J}}{208.8 \, \text{J/°C}} \approx 11.97 \textdegree C[/tex]
Add this change to the initial temperature of 30°C:
Final temperature = 30°C + 11.97°C = 41.97°C
Therefore, the final temperature of the benzene after adding 2500 J of energy is 41.97°C.
Amino acids are monomers that join together in complex macromolecules called _____.
A.
phospholipids
B.
proteins
C.
carbohydrates
D.
polysaccharides
Answers
Amino acids are building blocks in
proteins.
Proteins play numerous roles in cellular processes.
Amino acids combine to form complex macromolecules called proteins. Other listed macromolecules - phospholipids, carbohydrates, and polysaccharides - are not made from amino acids.
Explanation:Amino acids are the building blocks of proteins. They join together in a specific sequence to form these complex macromolecules. In the list provided, the correct answer is 'B. Proteins'. This is because phospholipids, carbohydrates, and polysaccharides are different types of macromolecules constructed from other monomers, not amino acids. The resulting protein structure determines its function in an organism.
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A) most reactions involve bond breaking and bond making. this equation shows what happens when methane (ch4) burns in oxygen (o2). mark the bonds broken in blue and the bonds formed in red.\
Answers
When CH₄ burns with the presence of O₂, CO₂ and H₂O are formed as the products. The balanced equation is;
CH₄ + 2O₂ → CO₂ + 2H₂O
When the reaction happens, 4 C-H bonds of CH₄ and O=O bond of O₂ are broken down to form 2 C=O bonds in CO₂ and 2 O-H bonds in H₂O.
The broken and formed bonds are marked in the image.
Question 13 unsaved the nonmetals in groups 5a, 6a, and 7a: question 13 options: lose electrons when they form ions. form ions with charges of 3-, 2-, and 1-, respectively. form positively charged ions. form ions with a numerical charge equal to their group number.
Answers
How does the law of conservation of mass apply to this reaction: C2H4 + O2 → H2O + CO2?
If hexane (c6h14), octane (c8h18), and octanol (c8h17oh) are heated evenly at different altitudes, rank them according to the order in which you would expect them to begin boiling.
Answers
At different altitudes the Hexane will boil first, followed by octane and octanol will boil at last.
Explanation:
The difference in the boiling point of these compounds is mainly due to difference in the intermolecular interactions found in them.
Hexane boils first as compared to other two because the interactions present in it are London Dispersion forces which is too present in octane but weaker than octane as the strength of London Dispersion forces increases with increase in carbon chain.
Octanol will have the greatest boiling point because it also has Hydrogen bond interactions along with London Dispersion forces which are considered the strongest intermolecular forces.
Relating ideas explain why ionic crystals melt at much higher temperatures than typical covalent molecular crystals.
Answers
In order for plants to go through photosynthesis, they must use
A. X rays.
B. visible light.
C. infrared rays.
D. ultraviolet light.
Answers
Reacting 35.4 ml of 0.220 m agno3 with 52.0 ml of 0.420 m k2cro4 results in what mass of solid formed
Answers
Chemical reaction: 2AgNO₃(aq) + K₂CrO₄(aq) → Ag₂CrO₄(s) + 2KNO₃(aq).
n(AgNO₃) = c(AgNO₃) · V(AgNO₃).
n(AgNO₃) = 0.220 M · 0.0351 L.
n(AgNO₃) = 0.0078 mol; limiting reactant.
n(K₂CrO₄) = 0.420 M · 0.052 L.
n(K₂CrO₄) = 0.022 mol.
From chemical reaction: n(AgNO₃) : n(Ag₂CrO₄) = 2 : 1.
n(Ag₂CrO₄) = 0.0078 mol ÷ 2.
n(Ag₂CrO₄) = 0.0039 mol.
m(Ag₂CrO₄) = 0.0039 mol · 331.73 g/mol.
m(Ag₂CrO₄) = 1.29 g.
What is the half-life of an isotope that decays to 6.25% of its original activity in 18.9 hours?
Answers
For 1st order reaction, we have
k = [tex] \frac{2.303}{t}Xlog \frac{\text{initial conc.}}{\text{final conc.}} [/tex]
where, k = rate constant of reaction
Given: Initial conc. 100, Final conc. = 6.25, t = 18.9 hours
∴ k = [tex] \frac{2.303}{18.9} X log \frac{100}{6.25} [/tex] = 0.1467 hours^(-1)
Now, for 1st order reactions: half life = [tex] \frac{0.693}{k} = \frac{0.693}{0.1467} [/tex] = 4.723 hours.
The half-life of an isotope that decays to 6.25% of its original activity in 18.9 hours is 4.725 hours. This is calculated by understanding that the isotope undergoes 4 half-lives to reach the 6.25% activity.
Explanation:The half-life (T1/2) of a radioactive isotope refers to the time period for half of the original nuclei to decay. In this case, the isotope decays to 6.25% of its original activity in 18.9 hours which means it goes through 4 half-lives (since (1/2)^4 = 1/16 which approximately equals 6.25%). Hence, the half-life of this isotope is 18.9/4 = 4.725 hours.
This concept is derived from the exponential decay of unstable radioisotopes where half-life (T1/2) is calculated by dividing the total time by number of half-lives.
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Which one of these elements is an alkaline earth metal
Answers
A 10.0ml sample of calcium hydroxide solution requirewd 26.85ml of 0.225 m hydrochoric acid for neutralization. calculate the nolar concentration of the bsae
Answers
Ca(OH)₂ + 2HCl ---> CaCl₂ + 2H₂O
stoichiometry fo Ca(OH)₂ to HCl is 1:2
number of HCl moles reacted - concentration of HCl x volume
number of HCl moles - 0.225 mol/L x 26.85 x 10⁻³ L = 6.041 x 10⁻³ mol
according to molar ratio
2 mol of HCl reacts with 1 mol of Ca(OH)₂
therefore 6.041 x 10⁻³ mol of HCl reacts with - 6.041 x 10⁻³ /2 mol = 3.021 x 10⁻³ mol
number of Ca(OH)₂ moles in 10.0 mL - 3.021 x 10⁻³ mol
therefore Ca(OH)₂ moles in 1000 mL - 3.021 x 10⁻³ mol / (10.0 x 10⁻³ L) = 0.302 mol/L
molarity of Ca(OH)₂ - 0.302 M
To calculate the molar concentration of the base, use stoichiometry and the given volume and concentration of the acid. The balanced chemical equation helps determine the moles of acid and base. Divide the moles of base by the volume of the base solution to find the molar concentration.
Explanation:To calculate the molar concentration of the base, we can use the stoichiometry of the neutralization reaction between calcium hydroxide (Ca(OH)2) and hydrochloric acid (HCl). The balanced chemical equation for this reaction is:
Ca(OH)2 + 2HCl → CaCl2 + 2H2O
From the equation, we can see that 1 mole of Ca(OH)2 reacts with 2 moles of HCl. We are given that 26.85 mL of 0.225 M HCl is required to neutralize a 10.0 mL solution of Ca(OH)2. The moles of HCl can be calculated using the equation:
moles of HCl = volume of HCl (L) × concentration of HCl (M)
Once we have the moles of HCl, we can use the stoichiometry of the reaction to calculate the moles of Ca(OH)2. Finally, we divide the moles of Ca(OH)2 by the volume of the Ca(OH)2 solution to find the molar concentration.
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How are elements with similar properties displayed in the periodic table?
Answers
What are silicates? what are silicates? silicates are extended arrays of silicon and nitrogen. they are the most common network covalent atomic solids. silicates are extended arrays of sulfur and oxygen. they are the most common network covalent atomic solids. silicates are extended arrays of silicon and oxygen. they are the most common network covalent atomic solids. silicates are extended arrays of silicon and oxygen. they are the least common network ionic atomic solids?
Answers
Answer:
silicates are extended arrays of silicon and oxygen.
Explanation:
By definition, a silicate is a compound consisting of the chemical elements silicon (Si) and oxygen (O), derived from salicylic acid, which may be a salt or an ester. Of this group stand out the silicates formed by the alkali metals, constituent elements of Family IA of the periodic table, which are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium. (Fr), as these are water soluble and have various applications in industry and the laboratory. This list excludes the last two elements mentioned, due to their high molecular weight and their radioactivity. It is also relevant to report that salicylic acid is one of the derivatives of the second most abundant chemical element in the earth's crust, of the order of 27%, silicon (Si).
Calculate the mass of agcl that should be produced when an excess of agno3 is reacted with 500 mg
Answers
Balanced chemical reaction:
2AgNO₃ + [Co(NH₃)₅Cl]Cl₂ → 2AgCl + [Co(NH₃)₅Cl](NO₃)₂.
m(Co(NH₃)₅Cl]Cl₂) = 500 mg ÷ 1000 mg/g = 0.5 g.
n(Co(NH₃)₅Cl]Cl₂) = 0.5 g ÷ 250.4 g/mol.
n(Co(NH₃)₅Cl]Cl₂) = 0.002 mol.
From chemical reaction: n(Co(NH₃)₅Cl]Cl₂) : n(AgCl) = 1 : 2.
n(AgCl) = 2 · 0.002 mol = 0.004 mol.
m(AgCl) = 0.004 mol · 143.32 g/mol.
m(AgCl) = 0.573 g.
Which determines whether the fire will have open flames?
Question 4 options:
flash point
fuel-air mix
exothermic energy
type of fuel
Answers
flash point - this is not the answer as it only denotes the minimum temperature required for vapors of something combustible will ignite
exothermic energy - is the energy released during the combustion reaction so this is not the answer
type of fuel - is not the general answer
The answer is fuel-air mix as it will determine the vigor of the flame.
How many grams of titanium (Ti, 47.90 g/mol) are in an instrument gear with 5.74x10^22 atoms of Ti
Answers
Mass = 45.64 g
Solution:
First of all calculate number of moles for given number of atoms,
As,
6.022 × 10²³ atoms = 1 Mole
So,
5.74 × 10²² atoms = X Moles
Solving for X,
X = (1 mol × 5.74 × 10²² atoms) ÷ 6.022 × 10²³ atoms
X = 0.953 Moles
Now converting moles into mass,
As,
Moles = Mass / M.mass
So,
Mass = Moles × M.Mass
Putting Values,
Mass = 0.953 mol × 47.90 g.mol⁻¹
Mass = 45.64 g
Answer:
Grams of Ti = 4.56 g
Explanation:
Given:
# atoms of Titanium = 5.74*10²²
To determine:
The mass of Ti in corresponding to the given number of atoms
Explanation:
1 mole of any substance contains Avogadro's number of atoms.
i.e. 1 mole of Ti = 6.023*10²³ atoms
Since 1 mole Ti = 47.90g,
47.90 g of Ti contains 6.023*10²³ atoms
Therefore, [tex]= \frac{5.74*10^{22} atoms*47.90g}{6.023*10^{23} atoms} =4.56\ g[/tex] of Ti would correspond to:
When the pressure that a gas exerts on a sealed container changes from 1100 bar to 75.5 bar, the temperature changes from k to 298 k?
Answers
P/T = k
where P - pressure , T - temperature and k - constant
[tex] \frac{P1}{T1} = \frac{P2}{T2} [/tex]
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
substituting the values in the equation
[tex] \frac{1100 bar}{T} = \frac{75.5 bar}{298 K} [/tex]
T = 4342 K
initial temperature was 4342 K
Answer:
4342 K
Explanation:
List a few ways that would lead you to believe a chemical reaction has occurred
Answers
Change in Color:
Few reactions proceed with the change in colour. When Bromine Water (yellow-Brown) is treated with unsaturated compounds, the color disappear as the reaction is completed.
Gas Production:
Some reactions proceed with the elimination of gas i.e. CO₂ , H₂, N₂, H₂O e.t.c.
Temperature Change:
Some reactions evolve or absorb heat when proceed. This change is the evidence of progress of reaction.
Thin Layer Chromatography:
Very important technique in detecting the progress of reaction by determining the number of spots for UV active compounds on TLC plate. Even non UV active compounds can be detected by using other locating agents.
Instrumental Techniques:
Modern techniques like IR, MS, NMR, UV spectroscopy can be used to detect the progress of reaction.
What is the molarity of a solution that contains 20.45 g of sodium chloride (NaCl) dissolved in 700.0 mL of solution?
Answers
the mass of NaCl added - 20.45 g
number of moles of NaCl - 20.45 g / 58.5 g/mol = 0.350 mol
volume of the solution is 700.0 mL
since molarity is the number of moles in 1000 mL
and if 700.0 mL contains - 0.350 mol
therefore 1000 mL contains - 0.350 mol / 700.0 x 1000 = 0.500 mol
hence molarity of solution is 0.500 M
what temperature does blood boil at (in Celsius Kelvin and Fahrenheit)
Answers
Blood boils at a temperature close to water's boiling point: 100°C, 373 K, or 212°F. This boiling point slightly varies due to dissolved substances. Understanding these values illustrates the relationship among different temperature scales.
When considering the temperature at which blood boils, it primarily depends on its composition, but generally, it is close to the boiling point of water. The boiling point of water is an important reference and is commonly known for each temperature scale:
Celsius (°C): Water boils at 100°C.Kelvin (K): Water boils at 373 K.Fahrenheit (°F): Water boils at 212°F.Human blood is mostly water, and hence its boiling point is similarly close; however, due to the presence of dissolved proteins, salts, and other substances, the exact boiling point may slightly vary. At normal atmospheric pressure, it is approximately 100°C (373 K or 212°F). This concept is an important illustration of the relationship among the temperature scales.
What will happen to the volume if the number of moles of a gas is decreased at constant temperature and pressure? The volume will increase. The volume will decrease. The volume will remain the same. The volume will be negative.
Answers
Answer:
The volume will decrease.
Explanation:
The number of moles of a gas is directly proportional to its volume according to Avogadro's law. Hence volume increases as number of moles increases. Volume also decreases as number of moles decreases.
Hence according to the question, when the number of moles of a gas decreases, the volume of the gas also decreases along side in obedience to the Avogadro's law.
When an arrhenius base is dissolved in h2o, the only negative ion present in the solution is?
Answers
An Arrhenius base is a substance that dissociates in water to form hydroxide ions (OH⁻).
For example sodium hydroxide: NaOH(aq) → Na⁺(aq) + OH⁻(aq) or barium hydroxide: Ba(OH)₂(aq) → Ba²⁺(aq) + 2OH⁻(aq).
According to this theory acids are substances which produce hydrogen ions in water solution.
Write a general word equation for a neutralization reaction.
Answers
Final answer:
In a neutralization reaction, an acid reacts with a base to form salt and water, and the net ionic equation for this reaction usually involves hydrogen ions from the acid joining with hydroxide ions from the base to form water.
Explanation:
A general word equation for a neutralization reaction is: Acid + Base → Salt + Water
During neutralization, the hydrogen ions from the acid react with the hydroxide ions from the base to form water. The remaining ions (from the acid and base) then combine to form a salt. If we consider the neutralization of a strong acid with an ionic hydroxide, the net ionic equation simplifies to:
H3O+ (aq) + OH−(aq) → 2H2O(l)
This equation represents the concentration of hydrogen ions from the acid reacting with hydroxide ions from the base, simplifying down to just the formation of water since strong acids completely dissociate in water.
Nuclear power plants produce a waste product of cesium-137, which has a half-life of 30 years. how long would it take for the cesium to decay to 1/8 of its original amount?
Answers
[tex] \frac{1}{8} m(initial)=m(initial)*( \frac{1}{2})^{ \frac{time}{halg-life} } [/tex]
[tex] \frac{1}{8} = \left( \frac{1}{2} \right)^{\frac{time}{30} } [/tex]
[tex]( \frac{1}{2})^{3}= (\frac{1}{2} )^{ \frac{time}{30}} \\ \\ 3= \frac{time}{30} \\ \\ time = 90 (years)[/tex]
Answer:
90 years
Explanation:
it takes three halves of one to get to 1/8.
So 30 times 3 = 90
Which element is likely to be chemically unreactive? krypton (8 valence electrons) rubidium (1 valence electron) silicon (4 valence electrons) magnesium (2 valence electrons) bromine (7 valence electrons)?
Answers
1) Kr = [Ar] 3d10 4s2 4p6
2) Rb = [Kr] 5s1
3) Si = [Ne] 3s2 3p2
4) Mg = [Ne] 3s2
5) Br = [Ar] 3d10 4s2 4p5
From above listed electronic configurations of different elements, it can be seen that expect Kr, all the elements has partially filled atomic orbitals. Hence, they will be reactive in nature. So, Kr is likely to be chemically nonreactive.
If generating a key for this data, what is the correct sequence from bottom to top?
Answers
Generating a key from bottom to top signifies rearranging data in a particular order, often used in sorting or indexing processes. The actual sequence depends on the set rules, such as alphabetically or numerically.
Explanation:The correct sequence from bottom to top when generating a key for data, generally implies rearranging the data in a specific order. Let's consider a scenario in which we have data items named A, B, C, and D from bottom to top. In this case, the correct sequence from bottom to top might be D, C, B, A, assuming we're ordering in reverse-alphabetical order. However, the exact sequence can depend on the specific criteria or rules you're using to generate the key.
These keys are often used in computer operations such as sorting and indexing to manage and locate data efficiently. It's always important to understand the specific context in which the key is being applied for an accurate sequence.
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Which type of reaction is represented by the generic equation AB + CD mc002-1.jpg AD + CB?
Answers
This equation represents a Double Displacement Reaction.
Explanation:
Given equation is,
AB + CD → AD + CB
In above reaction A and C are switching their groups i.e. B and D. A has given off B to C and C has given D to A. Such reactions in which the cations and anions of two compounds are exchanged are called double displacement or double replacement reactions.