Define mass number of an atom.​

Answers

Answer 1
the mass number of an atom is basically the total number of protons and neutrons.

Related Questions

……….is strong due to the ……………..between positive ions and negative delocalized electrons

Answers

Answer:

atom &bond

Explanation:

atom is strong due to the bond

Using the following equation for the combustion of octane calculate the heat associated with the formation of 100.0 g of carbon dioxide. The molar mass of octane is 114.33 g/mole.

2C8H18 + 25O2 → 16 CO2 + 18 H2O

ΔH°rxn = -11018 kJ

Answers

Answer:

The right solution is "-602.69 KJ heat".

Explanation:

According to the question,

The 100.0 g of carbon dioxide:

= [tex]\frac{100.0 \ g}{114.33\ g/mole}[/tex]

= [tex]0.8747 \ moles[/tex]

We know that 16 moles of [tex]CO_2[/tex] formation associates with -11018 kJ of heat, then

0.8747 moles [tex]CO_2[/tex] formation associates with,

= [tex]-\frac{0.8747}{16}\times 11018 \ KJ \ of \ heat[/tex]

= [tex]-0.0547\times 11018[/tex]

= [tex]-602.69 \ KJ \ heat[/tex]

The mass of an empty crucible was 17.556g. The mass of the crucible and a hydrate was 21.018 g. The mass of the crucible and anhydrous salt (after heating) was 19.641g. A. Calculate the mass of water lost due to heating. B. Calculate the mass percentage of water.

Answers

Answer:

A. 1.377 g

B. 16.5%

Explanation:

To find the water loss, subtract the salt and crucible mass from the hydrate and crucible mass

21.018 - 19.641 = 1.377

To find the water mass percentage, divide the empty crucible mass by the mass of the hydrate and crucible. Then, subtract that number from 1.

17.556 ÷ 21.018 = 0.835284

1 - 0.835284 = 0.164716

If you want to add an extra step, multiply this number by 100 to get the percentage.

0.164716 x 100 = 16.4716

Which of the following events takes place in the Kreb entry phase (acetyl COA from pyruvate)?


A). Only CO2 output

B). NAD is reduced, CO2 is released

C). NADH is oxidized, CO2 is released

D). Only NADH is oxidized

E). Only NAD is reduceed

Answers

Answer:

Alphabet C :NADH is oxidized,CO2 is reduced

What is the molarity of an HCl solution if 25.0 mL of this solution required 17.80 mL of 0.108 M NaOH to reach the end point in a titration?

Answers

Answer:

[tex]\boxed {\boxed {\sf 0.0769 \ M}}[/tex]

Explanation:

We are asked to find the molarity of an acid given the details of a titration experiment. The formula for titration is as follows:

[tex]M_AV_A= M_B V_B[/tex]

In this formula, M is the molarity of the acid or base and V is the volume of the acid or base. The molarity of the hydrochloric acid (HCl) is unknown and the volume is 25.0 milliliters.

[tex]M_A * 25.0 \ mL = M_BV_B[/tex]

The molarity of the sodium hydroxide (NaOH) is 0.108 molar and the volume is 17.80 milliliters.

[tex]M_A * 25.0 \ mL = 0.108 \ M * 17.80 \ mL[/tex]

We are solving for the molarity of the acid and we must isolate the variable [tex]M_A[/tex]. It is being multiplied by 25.0 milliliters. The inverse operation of multiplication is division, so we divide both sides of the equation by 25.0 mL.

[tex]\frac {M_A * 25.0 \ mL }{25.0 \ mL}= \frac{0.108 \ M * 17.80 \ mL }{25.0 \ mL}[/tex]

[tex]M_A= \frac{0.108 \ M * 17.80 \ mL }{25.0 \ mL}[/tex]

The units of milliliters cancel.

[tex]M_A= \frac{0.108 \ M * 17.80 }{25.0 }[/tex]

[tex]M_A= \frac{1.9224}{25.0 } \ M[/tex]

[tex]M_A= 0.076896 \ M[/tex]

The original measurements have 3 and 4 significant figures. We must round our answer to the least number of sig figs, which is 3. For the number we calculated, that is the ten-thousandth place. The 9 to the right of this place tells us to round the 8 up to a 9.

[tex]M_A \approx 0.0769 \ M[/tex]

The molarity of the hydrochloric acid is 0.0769 Molar.

A/An is a type of blood cell that's also called a red blood cell. a) Jeukocyte O b) thrombocyte c) plasma d) erythrocyte

Answers

Answer:

option a

Explanation:

pls mark me as brainliest

1. Metallic strontium crystallizes in a face-centered cubic lattice, with one Sr atom per lattice point. If the edge length of the unit cell is found to be 608 pm, what is the metallic radius of Sr in pm?
2. The substance beta manganese is found to crystallize in a cubic lattice, with an edge length of 630.0 pm. If the density of solid beta manganese is 7.297 g/cm3, how many Mn atoms are there per unit cell?

Answers

Answer:

[tex]r=215pm[/tex]

[tex]N_{Mn}=20[/tex]

Explanation:

From the question we are told that:

Edge length of the unit cell [tex]l=608pm[/tex]

a)

Generally the equation for The relationship between edge length and radius is mathematically given by

[tex]4r=\sqrt{2a}[/tex]

Therefore

[tex]4r=\sqrt{2*608}[/tex]

[tex]r=\frac{\sqrt{2*608}}{4}[/tex]

[tex]r=215pm[/tex]

b)

From the question we are told that:

Density [tex]\rho=7.297[/tex]

Edge length of [tex]l=630.0 pm=>630*10^-{10}[/tex]

Therefore Volume  is given as

[tex]V=l^3[/tex]

[tex]V=630*10^-{10}^3[/tex]

[tex]V=2.50047*10^{−22}[/tex]

Generally the equation for Mass is mathematically given by

[tex]m=Volume*density[/tex]

[tex]m=V*\rho[/tex]

[tex]m=2.50047*10^{−22}*7.297[/tex]

[tex]m=1.83*10^{-21}g[/tex]

Therefore Molarity is given as

[tex]n=\frac{M}{Molar M}[/tex]

[tex]n=\frac{1.83*10^{-21}g}{55}[/tex]

[tex]n=3.32*10^{-23}[/tex]

Finally The atoms in a unit cell is

[tex]N_{Mn}=Moles*Avogadro\ constant[/tex]

[tex]N_{Mn}=3.32*10^{-23}*6.023*10^{23}[/tex]

[tex]N_{Mn}=20[/tex]

Determine which choice is an example of an endothermic process.
O A. Lighting a match
B. Respiration
C. Running a gas engine
D. Baking bread

Answers

Answer:

D. Baking bread

Explanation:

In this process, energy is absorbed and in an endothermic process energy is absorbed too.

Baking bread is an example of an endothermic process, therefore option (d) is correct .

What do you mean by endothermic process ?

Endothermic reactions are chemical processes in which the reactants absorb heat from the environment to produce products.

An endothermic reaction is  accompanied by an absorption of heat.

Endothermic  reactions cause a cooling effect by lowering the temperature of the surrounding environment.

A decrease in temperature can be observed with the progression of the reaction. The reaction is non-spontaneous in endothermic reactions .

Baking bread is an example of an endothermic process, hence  option (d) is correct .

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Can steel turn into gas? ( A random question that came to mind. I have no idea if it is or isn't possible.)

Answers

Answer:

YES STEEL CAN TURN INTO GAS .

Answer: yes it can!

Explanation:

In what areas of the periodic table do you find the most highly reactive elements?

Answers

Answer:

The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive.

The most highly reactive elements are typically found at the far left (Group 1) and far right (Group 17) of the periodic table.

Highly reactive elements in the periodic table

Group 1 elements, also known as alkali metals, are located on the far left of the periodic table. They have one electron in their outermost energy level and are highly reactive due to their tendency to lose that electron to achieve a stable electron configuration. This makes them very reactive with water and other substances.

Group 17 elements, known as halogens, are located on the far right of the periodic table. They have seven electrons in their outermost energy level and are highly reactive due to their strong tendency to gain one electron to achieve a stable electron configuration. This makes them reactive with metals and other elements.

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One of the electron transitions in a hydrogen atom produces infrared light with a wavelength of
8.231 x 10°m. What amount of energy causes this transition?

Answers

A transition occurs when an electron absorbs energy and moves from one energy level to another.

Let us recall the formula;

E = hc/λ

h= planks constant = 6.6 * 10^-34 Js

c = speed of light = 3 * 10^8 ms-1

λ = wavelength =

We can see from the question that the exponent in the value for the wavelength was not properly rendered hence we can not be able to substitute values and obtain a numerical answer for the energy of the infrared radiation.

However, if all the values are properly substituted, then the energy of the infrared radiation can conveniently be obtained.

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Explain why
when suger
is heated it
does not boil but rather break down
into carbon and water?

Answers

Answer:

When simple sugars such as sucrose (or table sugar) are heated, they melt and break down into glucose and fructose, two other forms of sugar. Continuing to heat the sugar at high temperature causes these sugars to lose water and react with each other producing many different types of compounds.

What is the concentration of Htions at a pH = 11?
mol/L
What is the concentration of Htions at a pH = 6?
mol/L
How many fewer Htions are there in a solution at a
pH = 11 than in a solution at a pH = 6?

Answers

Answer:
a) 1 x 10^-11 mol/L
b) 1 x 10^-6 mol/L
c) 1 x 10^-5 fewer H+ ions

Explanation

pH stands for Power of Hydrogen, the more acidic a substance is, the more H+ ions it has rendering the substance acidic. a pH of 1 means the concentration of H+ ions is 1 x 10^-1. A pH of 7 means the concentration of H+ ions is 1 x 10^-7 and so on.

10^-11 has 10^-5 more H+ ions than 10^-6

Hope this helps :)

When the equation,
O2 + __C 10H 22 →
CO2 +
H2O is balanced, the coefficient of O2 is?

Please help!

Answers

(10)O_2+C_10 H_22-->(10)CO_2+(11)H_2 O

This is the correct balanced equation

The coefficient would be (20) when you multiply 10 by 2

CH3CH2OH
______ions
in an aqueous solution.
А
forms
B
does not form

Answers

Answer:

When ionic compounds dissolve, they break apart into ions which are then able to conduct a current ( conductivity ). ... Many molecular compounds, such as sugar or ethanol, are nonelectrolytes. When these compounds dissolve in water, they do not produce ions.

Explanation:

Ethanol is an organic compound with an alcoholic functional group and is nonelectrolytes. Ethanol (CH₃CH₂OH) does not form ions in an aqueous solution. Thus, option B is correct.

What are nonelectrolytes?

Nonelectrolytes are substances that do not dissociate readily to yield ions and also are poor conductors of electricity and heat due to a lack of charged ions.

Ethanol is a nonelectrolyte that does not show conductivity and can be dissolved in water without producing ions. They cannot forms ions upon dissociation as covalent bonds are present.

Instead of ions that have covalent compounds that lack the ability to transfer the electron to conduct the electrical charge. Glucose, ethanol, etc. are some examples of a nonelectrolyte.

Therefore, option B. ethanol does not form ions is the correct blank.

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What does this graph show about the acceleration of the moving object?

the acceleration is constant
the object is not accelerating
the acceleration is decreasing
the acceleration is increasing

Answers

Answer:

the accleration is decreasing

Explanation:

I hpe so

Answer:

the acceleration is increasing

Explanation:

I took a test with a question that was phrased like this, so I'm assuming (hoping) that it's the same graph

When equal moles of an acid and a base are mixed, after reaction the two are compounds are said to be at the _______________. Select one: Indicator point Stoichiometric point Equilibrium point End point

Answers

Answer:

when equal moles of an acid and base are mixed,after reaction the two are compounds are said to be at the Equivalent point.

The element europium exists in nature as two isotopes: has a mass of u and has a mass of u. The average atomic mass of europium is u. Calculate the relative abundance of the two europium isotopes.

Answers

Answer:

Problem Details

The element europium exists in nature as two isotopes:  151Eu has a mass of 150.9196 amu, and 153Eu has a mass of 152.9209 amu. The average atomic mass of europium is 151.96 amu. Calculate the relative abundance of the two europium isotopes.

answer:

151Eu = 48%, 153Eu = 52%

Based on the following observations decide the order of reactivity for hydrogen, magnesium, and copper. Hydrochloric acid reacts with magnesium but did not react with copper. magnesium reacted with copper sulfate. Write your answers in the blanks. For magnesium write magnesium for hydrochloric acid write hydrogen and for copper sulfate write copper.

Answers

Answer:

Mg> H> Cu

Explanation:

We can see from the question that hydrochloric acid reacted with magnesium as follows;

Mg(s) + 2HCl(aq) ----> MgCl2(aq) + H2(g)

Copper does not react with HCl which means that copper is less reactive than hydrogen hence it can not displace hydrogen from a dilute acid solution.

The order of reactivity of the elements then is ; Mg> H> Cu

Given the equation representing a nuclear reaction in
which X represents a nuclide:
232Th → He + x
Which nuclide is represented by X?
A) 236
B) 228
Ra
SS
C) 236
Ra
92
U
92
D) 228
.
Ss U

Answers

The nuclide represented as X is thorium and this is an alpha decay.

The equation shown represents an alpha decay. In an alpha decay, an alpha particle is given off.

The atomic number of the parent nuclide is greater than that of the daughter nuclide by two units while the mass number of the parent is greater than that of the daughter nuclide by four units.

Hence the equation occurs as follows;

[tex]\frac{232}{92} Th ------> \frac{228}{88} Ra + He[/tex]

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Titration of 25.0 mL of an HCl solution of unknown concentration requires 14.8 mL of 0.100 M NaOH. What is the molar concentration of the HCl solution

Answers

M1V1 = M2V2
M1 = 0.100 M NaOH
V1 = 14.8 mL NaOH
M2 = ?
V2 = 25.0 mL HCl

(0.100 M)(14.8 mL) = M2(25.0 mL)

M2 = 0.0592 M HCl

Could someone please help me out???

Answers

Answer:

Time is 2.2 seconds.

Explanation:

Time:

[tex]{ \boxed{ \bf{time = \frac{distance}{speed} }}}[/tex]

Substitute into the formula:

speed = 715 km/h = 198.61 m/s

[tex]{ \tt{time = \frac{435}{198.61} }} \\ { \tt{time = 2.2 \: seconds}}[/tex]

ort
Which is a primary alcohol?
0 3-pentanol
2-propanol
1-ethanol
4-octanol
urvey
Lig A Moving to another question will save this response.

Answers

Answer:

1 ethanol is right answer

Explanation:

CH3- CH2-OH

Determine the total pressure of a mixture that contains 5.25 g of He and 3.25 g of N2 in a 7.75-L flask at a temperature of 27ºC.

Answers

Answer:

4.54 atm

Explanation:

Step 1: Calculate the total number of gaseous moles

We will calculate the moles of each gas using its molar mass.

He: 5.25 g × 1 mol/4.00 g = 1.31 mol

N₂: 3.25 g × 1 mol/28.01 g = 0.116 mol

The total number of moles is:

n = 1.31 mol + 0.116 mol = 1.43 mol

Step 2: Convert 27 °C to Kelvin

We will use the following expression.

K = °C + 273.15 = 27 + 273.15 = 300 K

Step 3: Calculate the total pressure of the mixture

We will use the ideal gas equation.

P × V = n × R × T

P = n × R × T / V

P = 1.43 mol × (0.0821 atm.L/mol.K) × 300 K / 7.75 L = 4.54 atm

A bio catalyst that increases the rate of the reaction without being changed
a) Aluminum oxide. b) Silicon dioxide. c) Enzyme. d) Hydrogen peroxide
43. What is the
than the reaction substrate.
42. A

Answers

Explanation:

Enzymes are proteins functioning as catalysts that speed up reactions by lowering the activation energy. A simple and succinct definition of an enzyme is that it is a biological catalyst that accelerates a chemical reaction without altering its equilibrium.

12 g of powdered magnesium oxide reacts with nitric acid to
form magnesium nitrate and water.
Calculate the mass of magnesium nitrate formed.
[Relative atomic mass of Mg = 24, N = 14,0 = 16] *

Answers

Answer:

80.8 g

Explanation:

First, let's write a balanced equation of this reaction

MgO + 2HNO₃ → Mg(NO₃)₂ + H₂O

Now let's convert grams to moles

We gotta find the weight of MgO

24 + 16 = 40 g/mol

12/40 = 0.3 moles of MgO

We can use this to find out how much Magnesium Nitrate will be formed

0.3 x 1 MgO / 1 Mg(NO₃)₂ = 0.3 moles of Magnesium Nitrate formed

Convert moles to grams

Find the weight of Mg(NO₃)₂ but don't forget that 2 subscript acts as a multiplier of whatever is inside that parenthesis.

24 + 14 x 2 + 16 x 3 x 2 = 148 g/mol

148 x 0.3 = 80.8 g

name two device that are using spinning​

Answers

Two device that are using spinning

Takli

Takli is a small support style spindle. Takli is a perfect tool for spinning cotton, and this are used too to spin fibers, cotton, cashmere, and silk etc. Takli is known as handspindle. And it is the simplest device for spinning.

Charkha

Charkha is a device for spinning thread or yarn from fibers etc. This are known as spinning wheel.

HAVE A NICE DAY!

In practice, the second law of thermodynamics means that:

a. Systems move from ordered behavior to more random behavior.
b. Systems move from random behavior to more ordered behavior.
c. Systems move between ordered and random behavior patterns based on temperature.
d. Systems are constantly striving to reach equilibrium.

Answers

Answer:

Systems move from ordered behavior to more random behavior.

Explanation:

Entropy refers to the degree of disorderliness in a system. The second law of thermodynamics can be restated in terms of entropy as follows; “any spontaneous process in any isolated system always results in an increase in the entropy of that system.''(science direct)

According to this law, systems tend towards a more disorderly behaviour (increase in entropy) hence the answer given above.

(GIVING BRAINIEST!)
Which of the following compares the rainforest and the tundra environments correctly?

A. A rainforest is hotter than the tundra because it is closer to the equator.
B. A rainforest is less humid than the tundra because of its higher elevation.
C. A tundra has higher temperatures than the rainforest because it receives more
sunshine.
D. A tundra has higher humidity than the rainforest because of its proximity to water bodies.
For Science BTW!

Answers

Answer:

A

Explanation:

A rain forest is hotter than the tundra because it is closer to the equator

The predominant consequence to an individual who is genetically deficient in liver fructose 1,6-bisphosphatase would be

A. Inability to metabolize fructose.

B. a lowered yield of ATP production per mole of glucose metabolized.

C. a failure to split fructose bisphosphate into triose phosphates.

D. a failure to resynthesize glucose from lactic acid.​

Answers

The predominant consequence to an individual who is genetically deficient in liver fructose 1,6-bisphosphatase would be failure to resynthesize glucose from lactic acid.

WHAT IS FRUCTOSE 1,6-BISPHOSPHATASE:

fructose 1,6-bisphosphatase is an important enzyme produced in the liver to catalyze the conversion of fructose-1,6-bisphosphate to fructose-6-phosphate during gluconeogenesis.

Gluconeogenesis is the process whereby glucose sugar is produced from noncarbohydrate substances such as lactate, pyruvate etc. Gluconeogenesis is the opposite of glycolysis (breakdown of glucose).

CONSEQUENCES OF DEFICIENCY OF FRUCTOSE 1,6-BISPHOSPHATASE:

Since, gluconeogenesis results in the synthesis of glucose from substances like lactic acid, a deficiency in liver fructose 1,6-bisphosphatase enzyme will mean that GLUCOSE WILL NOT BE ABLE TO BE SYNTHESIZED.

Therefore, the predominant consequence to an individual who is genetically deficient in liver fructose 1,6-bisphosphatase would be failure to resynthesize glucose from lactic acid.​

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