The mass number of an atom can be calculated from the

Answers

Answer 1

Mass number (A) =protons (p+) + neutrons(n°)


Related Questions

Suppose you have a solution that might contain any or all of the following cations: Cu 2, Ag , Ba 2, and Mn2 . The addition of HBr causes a precipitate to form. After the precipitate is filtered off, H2SO4 is added to the supernate, and another precipitate forms. This precipitate is filtered off, and a solution of NaOH is added to the supernatant liquid until it is strongly alkaline. No precipitate is formed. Which ions are present in each of the precipitates

Answers

Answer:

Ag⁺, Ba²⁺,

Explanation:

We can solve this question using the solubility rules:

When an Halide as Br- is added to a solution, the ions that can be precipitate are Ag⁺, Hg₂²⁺ and Pb²⁺.

That means the first ion present is Ag⁺

When sulfates, SO₄²⁻ are added, the ions that precipitates are: Ag⁺, Ca²⁺, Sr²⁺, Ba²⁺, Hg₂²⁺ and Pb²⁺

The second ion present is Ba²⁺

Hydroxides of Cu²⁺ and Mn²⁺ are insolubles but as no precipitate are formed when the solution is strongly alkaline those ions are not present.

A 0.227 mol chunk of dry ice (solid CO2) changes to gas. What is the volume of that gas measured at 27 °C and 740 mmHg?

Answers

Answer:

Explanation:3.2 ft 2 fti2 ft 4 ft ft2

Andrea is making a poster to show how the nervous system uses signals to send information through the body. These signals are sent through nerves. What parts should Andrea include in her diagram of a nerve as evidence to support her explanation?



neurons only


neurons, axons, and dendrites


dendrites, blood vessels, and muscle cells


axons, blood vessels, and connective tissue

Answers

Answer:b

Explanation:

How much ammonia would it take to neutralize 5ml of apple cider and 5ml of white vinegar if the ammonia had a molarity of 0.25?

Answers

Answer:

[tex]m_{NH_3}=0.0213gNH_3[/tex]

Explanation:

Hello there!

In this case, since it is known that the reaction between ammonia and acetic acid is:

[tex]CH_3COOH+NH_3\rightarrow CH_3COONH_4[/tex]

It is possible for us to realize that the mole ratio of acetic acid (vinegar) to ammonia is 1:1, that is why we can relate the concentrations as follows:

[tex]M_{acid}V_{acid}=M_{base}V_{base}\\\\[/tex]

In such a way, by knowing that the volume of these two are the same, we infer that their concentrations is also de same; and therefore, the mass of ammonia is calculated as:

[tex]m_{NH_3}=0.005L*0.25\frac{molNH_3}{L}*\frac{17.04gNH_3}{1molNH_3}\\\\m_{NH_3}=0.0213gNH_3[/tex]

Regards!

Which laws protect citizens against human trafficking​

Answers

Answer:

It depends on the country you are coming from. For example, the human trafficking laws in the US are different from UK. If you need an essay on this contact me on (irenedavid at g mail dot com)

Explanation:

Can someone give me an example of balancing equations with a solution that is simple?​

Answers

Explanation:

[tex]H _{2}O _{2(aq)} →H _{2}O _{(l)} + O _{2}(g) \\ solution : 2 \: and\: 2[/tex]

Here is an example
The equation:
K + HOH -> KOH + H2 (an example of a single replacement reaction)
Balanced equation:
2 K + 2 HOH -> 2 KOH + 1 H2

What is the pH of a 0.025 M HCl solution?
12.4
1.6
2.5
05

Answers

Answer:  pH is 1.6

Explanation: Explanation: HCl is strong acid and it protolyzes totally:

HCl + H2O  ⇒ H3O+ + Cl-

Concentrations are same:  [H3O+] = c(HCl)

pH = - log[H3O+] = - log(0.025) = 1.60

What is the pOH of .12 M HNO3.

Answers

we will calculate pH of nitric acid of 0.1 M concentration. So, concentration of hydrogen ions in HNO3 is 0.1 M. And now by using this formula we will find pOH. So, from this we can say that pH of HNO3 is 1 and pOH of HNO3 is 13.

There are 6 different organisms in the picture above. Organize them into 2 or more groups AND defend your groups by
providing details about why you put them into the chosen groups.
Example on how to answer:
Group 1- XYZ
Group 2-LM
Group 3- PORS
I put XYZ in group 1 because...
I put LM together because...
I grouped PORS together because...

Answers

Explanation: they could be grouped by how they reproduce or they can be grouped by if there hetero or autotrophic

A or B or C or D, plz answer fassttt

Answers

Answer:

A.

Explanation:

They'd probably want to know the conditions that usually produce fog

9. Assuming all other conditions are constant, what is the new pressure of a gas if the original pressure is 50 kPa and the Kelvin temperature is doubled?
a.100kpa
b.25kpa
or D.200kpa​

Answers

Answer:

Option a (100 kPa) is the appropriate option.

Explanation:

The given value is:

Original pressure,

P₁ = 50 kPa

Let the new pressure be "x".

Now,

⇒  [tex]\frac{P1}{T_1} =\frac{P_2}{T_2}[/tex]

On substituting the values, we get

⇒  [tex]\frac{50}{T_1} =\frac{x}{2T_1}[/tex]

On applying cross-multiplication, we get

⇒  [tex]x = 50\times 2[/tex]

⇒     [tex]=100 \ kPa[/tex]

Thus the answer above is the right one.

PLS HELP ASAP I ONLY HAVE 7 min
On which of the following factors does the amount of energy absorbed by an endothermic reaction depend?

1. Number of reactants
2. Physical state of the reactant
3. Sum of the potential energy of the reactants and products
4. Difference in the potential energy of the reactants and products

Answers

Answer:

Option 3 and 4

Explanation:

In an endothermic reaction, the potential energy of the system increase. The potential energy of the reactant is less as compared to the potential energy of the products and hence additional energy is required to produce products.

The potential energy of the reactants depend on their chemical state and not the physical state. Hence, option 2 is not correct. Also, the number of reactant do not make any significant impact on the determination of potential energy of reactants. Thus, option 1 is also incorrect

Calculate the pressure of 2.50 Liters of a gas at 25.0oC if it has a volume of 4.50 Liters at
STP.

Answers

Answer:

P_2 =0.51  atm

Explanation:

Given that:

Volume (V1) = 2.50 L

Temperature (T1) = 298 K

Volume (V2) = 4.50 L

at standard temperature and pressure;

Pressure (P1) = 1 atm

Temperature (T2) = 273 K

Pressure P2 = ??

Using combined gas law:

[tex]\dfrac{P_1V_1}{T_1} = \dfrac{P_2V_2}{T_2} \\ \\ \dfrac{1 *2.5}{298} = \dfrac{P_2*4.5}{273}[/tex]

[tex]0.008389261745 \times 273 = 4.5P_2[/tex]

[tex]P_2 =\dfrac{0.008389261745 \times 273 }{4.5}[/tex]

[tex]P_2 =0.51 \ atm[/tex]

Hydrogen iodide can decompose into hydrogen and iodine gases. 2HI(g) H2(g) I2(g) K for the reaction is 0.016. Of 0.148 atm of HI(g) is sealed in a flask, what is the pressure of each gas when equilibrium is established

Answers

Solution :

Given :

Hydrogen iodide decomposes to hydrogen and iodine gas

    [tex]$2 HI \ \ \ \Leftrightarrow \ \ \ \ H_2 \ \ \\ + \ \ I_2 $[/tex]

I    0.148            0          0

C     -2a           +a          +a

E  0.148-2a      a            a

We know

[tex]$k_p=\frac{P(H_2)P(I_2)}{P(HI)^2}$[/tex]

[tex]$0.016=\frac{a^2}{(0.148-2a)^2}$[/tex]

[tex]$0.016^{1/2}=\frac{a}{0.148-2a}$[/tex]

[tex]$0.12649=\frac{a}{0.148-2a}$[/tex]

0.0187 = 1.2529 a

a = 0.0149

Therefore

P(HI) = 0.148 - 2a

        = 0.148 - 2(0.0149)

        = 0.1182 atm

P([tex]$H_2$[/tex]) =  a

        = 0.0149 atm

P([tex]$I_2$[/tex]) =  a

        = 0.0149 atm

can someone please do the balanced equation for potassium fluoride?​

Answers

Answer:

K + F2 = KF

Explanation:

Thats the balancee equation for potassium fluoride. The equation is 2K + F2 → 2KF and the balanced equation is K + F2 = KF

A chemical engineer must calculate the maximum safe operating temperature of a high-pressure gas reaction vessel. The vessel is a stainless-steel cylinder that measures 39.0cm wide and 46.8cm high. The maximum safe pressure inside the vessel has been measured to be 5.30MPa. For a certain reaction the vessel may contain up to 7.20kg of sulfur hexafluoride gas. Calculate the maximum safe operating temperature the engineer should recommend for this reaction. Write your answer in degrees Celsius. Round your answer to 3 significant digits.

Answers

Answer:

Maximum safe operating temperature = 450 °C

Explanation:

First, the volume of the cylindrical vessel is determined using the formula:

v = πr²h

Radius, r, of stainless steel vessel = width or diameter / 2

r = 39.0 cm / 2 = 19.5 cm

height of vessel = 46.8 cm

volume of cylinder = 22/7 × 19.5² × 46.8 = 55929.343 cm³ = 0.05593 m³

Using the ideal gas equation to calculate the maximum safe temperature

PV = nRT

pressure, P = 5.30 MPa = 5.30 × 10⁶ Pa

R = 8.314 J/mol.K

n = mass of gas/ molar mass of gas

molar mass of SF₆ = 146 g/mol

mass of Sf₆ = 7.20 kg = 7200 g

n = 7200/146 = 49.315 moles

T = PV/nR

T = (5.30 × 10⁶ × 0.05593) / (49.315 × 8.314)

T = 722.98 K

T in °C = 714.98 - 273.15 = 449.83 °C

Therefore, maximum safe operating temperature = 450 °C

2. All of the following statements are true regarding wood versus metal except: a) Wood has better electrical insulation which decreases with moisture content b) Wood structures dampen vibrations much better than metal, due to internal friction within the materials c) Under sustained loads wood stops to deform d) Wood has much better R value than metals

Answers

Answer:

All of the following statements are true regarding wood versus metal except:

c) Under sustained loads wood stops to deform

Explanation:

Wood is known to deform under stress.  It undergoes warping, thereby, losing its original straight shape when its moisture unevenly dries up.  Even concrete deforms under long-time loads.  Similarly, wood, under sustained loads, experiences faster deformation than it ordinarily warps.  To prevent further wood deformation, it must be treated, and its moisture dried up evenly.

How is water important to many branches of science?

Answers

Answer:

Water is capable of dissolving a variety of different substances, which is why it is such a good solvent. And, water is called the "universal solvent" because it dissolves more substances than any other liquid. This is important to every living thing on earth.

Which statement below can NOT
be used when describing volume?
A. Volume is the amount of space that an object
occupies.
B. The volume of an object is the same as the
weight of that object.
C. Volume can be measured in cubic
centimeters.
D. Volume is calculated using a formula: V = 1x w
xh.

Answers

Answer:

the answer is B:

Explanation:

I hope it help.

During a combustion reaction, 9.00 grams of oxygen reacted with 3.00 grams of CH4.

What is the amount of the leftover reactant?

0.74 grams of methane
0.89 grams of methane
1.22 grams of oxygen
1.45 grams of oxygen

Answers

Answer:d

Explanation:

What is the freezing point (in °C) of a 0.743 m
aqueous solution of KCI?
Enter your rounded answer with
3 decimal places.
K; for water = 1.86 °C/m

Answers

Answer: The freezing point (in °C) of a 0.743 m aqueous solution of KCI is [tex]2.763^{o}C[/tex].

Explanation:

Given: Molality = 0.743 m

[tex]K_{f}[/tex] for water = [tex]1.86^{o}C/m[/tex]

The equation for dissociation of KCl when dissolved in water is as follows.

[tex]KCl \rightarrow K^{+} + Cl^{-}[/tex]

As it is giving 2 ions. Therefore, Van't Hoff factor for it is equal to 2.

Formula used to calculate the freezing point is as follows.

[tex]\Delta T_{f} = i \times K_{f} \times m[/tex]

where,

i = Van't Hoff factor

[tex]K_{f}[/tex] = molal depression constant

m = molality

Substitute the values into above formula as follows.

[tex]\Delta T_{f} = i \times K_{f} \times m\\= 2 \times 1.86^{o}C/m \times 0.743 m\\= 2.763^{o}C[/tex]

Thus, we can conclude that the freezing point (in °C) of a 0.743 m aqueous solution of KCI is [tex]2.763^{o}C[/tex].

Which of the first four radioisotopes in the decay series has the longest half-life? Pa-234 Th-234 U-234 U-238

Answers

Answer:

can u explain a little more then i will help like what are the four

Explanation:

Answer:

d) U-238

Explanation:

edg 2021

Which statement describes the atoms in an element

Answers

Answer:

Atoms are kind of like building blocks.

Explanation:

Think of atoms as kind of like a mix between paint pigments and legos. The more legos that you have, the bigger the molecule but keep in mind that there are many different kinds of legos that all can come together to build numerous things. I hope that I answered your question and i apoligize if I didn't.

_____ the irregular break of a mineral.
a. Habit
b. arrangement
c. cleavage
d. Fracture.​

Answers

Answer:

D Fracture

Explanation:

jus took the test

D. Fracture, it means an irregular break.

The rate of reaction was measured during a chemical reaction. After the first 3 seconds, the rate of reaction was 1.8 x10−6 M/s. Which of the following would you expect after another 3 seconds?

Answers

The question is incomplete, the complete question is;

The rate of reaction was measured during a chemical reaction. After the first 3 seconds, the rate of reaction was 1.8 x10−6 M/s. Which of the following would you expect after another 3 seconds? a

The rate would be higher, and the concentration of reactants would be lower.

b

The rate would be higher, and the concentration of reactants would be higher.

c

The rate would be lower, and the concentration of reactants would be lower.

d

The rate would be lower, and the concentration of reactants would be higher.

Answer:

The rate would be lower, and the concentration of reactants would be lower.

Explanation:

The rate of reaction refers to how quickly or slowly the reactants disappear or the products appear in a given reaction. The rate of reaction depends on the concentration of the reactants. Thus, as concentration decreases with time, the rate of reaction decreases accordingly.

Therefore, reaction rates tend to decrease with time since the concentration of  the reactants decrease with time as the reactants are being converted into products. Thus after three seconds, the rate would be lower, and the concentration of reactants would be lower. Hence the answer above.

Answer:

The rate would be lower, and the concentration of reactants would be higher.

Explanation:

I took the test and i think i got it right

For the following reaction conditions select the correct statement regarding the reaction below.
OH Cl OTs OTs N TsCl W X Y Z N
a. W is the correct product.
b. X is the correct product.
c. Y is the correct product.
d. Z is the correct product since pyridine acts as a nucleophile.
e. Both X and Y are both formed in this reaction as a racemic mixture

Answers

Answer:

B

Explanation:

The appropriate diagram of the question is shown in the first image attached below.

From the diagram, we see the reaction of Cyclopentanol taking place under Tscl pyridine. We are to show the reaction mechanism and determine from the options, which appropriate product fits in.

So, from the reaction, the hydroxyl substituent reacts with Tscl where cl is being lost. This process is followed by an attack of N substituent on the pyridine with the Hydrogen atom and cleaves off for the structure to form a stable structure. The stereochemistry of the compound remains unchanged and it maintains its stick formula.

Thus, X is the appropriate and the correct product.

What is the volume of 1.00 kg of mercury?

Answers

Answer:0.074 L

Explanation:

=jskidwkjicdovfojvoeeeeeeeeeeeeeeeeeeeeeeeec

Answers

Answer:

you need a theripist or maybe just your girl if this is your question.

Explantion: you are clearly very weird but very cute and ily.

g Which of the following is TRUE for a system that is in dynamic equilibrium? Which of the following is TRUE for a system that is in dynamic equilibrium? The concentration of products is equal to the concentration of the reactants. The forward reaction goes to 100% completion. Both the forward and reverse reactions come to a halt. The reaction rate of the forward reaction approaches zero. none of the above

Answers

Answer:

none of the above

Explanation:

A system is said to have attained dynamic equilibrium when the forward and reverse reactions proceed at the same rate. That is;

Rate of forward reaction = Rate of reverse reaction

The implication of this is that the concentrations of reactants and products remain constant when dynamic equilibrium is attained in a system. This does not mean that the reactant and product concentrations become equal; it rather means that their concentrations do not significantly change once dynamic equilibrium has been attained.

What physical property describes the ability of a substance to dissolve?

Answers

Answer:

solubility

Explanation:

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