It’s due in 3 minutes please help

Answer:

false

Explanation:

A compound has the combined properties of the elements from which it is made. Atoms show the macro properties of an element.

Answer:

Energy released =  18.985 J

Explanation:

The  exponential decay of radioactive substance is given by -

N(t) = N₀ [tex]e^{-kt}[/tex]

where

N₀ = initial quantity

k = decay constant

Half life, [tex]t_{1/2} = \frac{ln 2}{k}[/tex]

⇒[tex]k = \frac{ln 2}{t_{1/2} }[/tex]

Given,

N₀ = 12.5 + 3 = 15.5 × 10⁻⁶ gm

[tex]t_{1/2}[/tex] = 32.6 + 18 = 50.6 × 10⁶ years

So,

[tex]k = \frac{ln 2}{50.6 * 10^{6} }[/tex] = 1.361 × 10⁻⁸ year⁻¹

Now,

N(1) = 15.5 × 10⁻⁶  [tex]e^{-1.361*10^{-8} *1}[/tex]

      = 15.49999978904

Now,

Substance decayed = N₀ - N(t)

                                 = 15.5 × 10⁻⁶ - 15.49999978904 × 10⁻⁶

                                 = 21.095 × 10⁻¹⁷ kg

⇒Δm = 21.095 × 10⁻¹⁷ kg

So,

Energy released = Δmc²

                           = 21.095 × 10⁻¹⁷ × 3 ×10⁸ × 3 × 10⁸

                          = 189.855 ×10⁻¹

                          = 18.985 J

⇒Energy released =  18.985 J

Answer:

Heat absorbed = mS△T

51 = ( 8.2/1000)Kg ×S (11.5)

51×1000= 8.2 (11.5)S

S = 51000/94.3

S = 540.8 J/kg K

Answer: Both males and females have sharp, curved horns extending from the sides of their heads which are used to defend themselves against predators.

Explanation:

At STP, 1 mole of any gas occupies 22.4 L of space. Since we are given STP conditions here, we can use this ratio to determine the number of moles of CO gas: (32.8 L CO)/(22.4 mol CO/L CO) = 1.51 mol CO.

So, there are 1.51 moles of CO gas.

Answer:

I would choose E

Explanation:

Chemical reactions occur when chemical bonds between atoms are formed or broken. The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products

web-

Answer:

0.95 L

Explanation:

Step 1: Given data

Concentration of the Mg(NO₃)₂ solution (C): 0.32 M (0.32 mol/L)

Mass of Mg(NO₃)₂ (solute): 45 g

Step 2: Calculate the moles corresponding to 45 g of Mg(NO₃)₂

The molar mass of Mg(NO₃)₂ is 148.33 g/mol.

45 g Mg(NO₃)₂ × 1 mol Mg(NO₃)₂ /148.33 g Mg(NO₃)₂ = 0.303 mol Mg(NO₃)₂

Step 3: Calculate the volume of solution that contains 0.303 moles of Mg(NO₃)₂

The concentration of the solution is 0.32 M, that is, there are 0.32 moles of Mg(NO₃)₂ per liter of solution.

0.303 mol Mg(NO₃)₂ × 1 L Solution / 0.32 mol Mg(NO₃)₂ = 0.95 L

Answer:

The question wants you to determine the energy that the incoming photon must have in order to allow the electron that absorbs it to jump from

n

i

=

2

to

n

f

=

6

.

A good starting point here will be to calculate the energy of the photon emitted when the electron falls from

n

i

=

6

to

n

f

=

2

by using the Rydberg equation.

1

λ

=

R

⋅

(

1

n

2

f

−

1

n

2

i

)

Here

λ

si the wavelength of the emittted photon

R

is the Rydberg constant, equal to

1.097

⋅

10

7

m

−

1

Plug in your values to find

1

λ

=

1.097

⋅

10

7

.

m

−

1

⋅

(

1

2

2

−

1

6

2

)

1

λ

=

2.4378

⋅

10

6

.

m

−

1

This means that you have

λ

=

4.10

⋅

10

−

7

.

m

So, you know that when an electron falls from

n

i

=

6

to

n

f

=

2

, a photon of wavelength

410 nm

is emitted. This implies that in order for the electron to jump from

n

i

=

2

to

n

f

=

6

, it must absorb a photon of the same wavelength.

Answer and Explanation:

The empty spaces should be completed step-by-step as follows:

First line:

Element symbol: La (it is the corresponding element for the atomic number 57)

Mass number = Atomic number + Neutrons = 57 + 82 = 139

Nuclear symbol: ¹³⁹₅₇ La because the atomic number is 57 and mass number is 139.

Protons: 57 (is equal to the atomic number for a neutral atom)

Electrons in neutral atom = Atomic number = 57

Second line:

Element symbol: La (it is the corresponding element for the atomic number 57 and mass number 138)

Atomic number: 57 (from the Periodic Table, for La)

Mass number = 138 (from the nuclear symbol)

Protons: 57 (is equal to the atomic number for a neutral atom)

Neutrons = Mass number - Atomic number = 138 - 57 = 81

Electrons in neutral atom = Atomic number = 57

Third line:

Atomic number: 26 (from the Periodic Table, for the element Fe)

Protons: 26 (is equal to the atomic number for a neutral atom)

Neutrons = Mass number - Atomic number = 59 - 26 = 33

Nuclear symbol: ⁵⁹₂₆ Fe because the atomic number is 26 and mass number is 26.

Answer:

6.12 L

Explanation:

Given that,

Initial volume, V₁ = 5 L

Initial temperature, T₁ = 7.0°C = 343 K

Final temperature, T₂ = 147°C = 420 K

We need to find its new volume. The relation between volume and temperature is given by :

[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\\\\V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{5\times 420}{343}\\\\V_2=6.12\ L[/tex]

So, the new volume is 6.12 L.

Answer:

Bicarbonate neutralizes the acidity of Lidocaine and hence reduce the pain

Explanation:

Alkalinization by addition of sodium bicarbonate causes buffering of local anesthetics and hence produce faster anesthetic effect such as pain control, pain reduction while injecting the patient and  faster onset of local anesthetics.

Lidocaine along with epinephrine results into acidic compound wit respect to subcutaneous tissue. Hence, when bicarbonate is added, it neutralizes the acidity of Lidocaine and hence decrease the pain.  

Answer:

A.

Explanation:

You should NEVER eat or drink anything in a lab area. You never know what chemicals or gases are in the lab, and they can harm you.

Wearing a drawstring hoodie won't protect you from chemicals.

Don't wait to clean up chemicals, immediately get a teacher and clean it up (follow the teachers instructions). You never know what has spilled, and if it is harmful or not, or if there is a certain procedure to clean it up.

Don't change the equipment in the middle of an experiment. This can tamper with your results, and depending on what you are working with, this can be dangerous.

Answer:

Aeration,flocculation,coagulation.

Explanation:

Answer:

.

Explanation:

A condition in which bones become weak and brittle.

The body constantly absorbs and replaces bone tissue. With osteoporosis, new bone creation doesn't keep up with old bone removal.

thus 2) is correct.

a disease in which bone tissue becomes breakable and thin.

if it helps don't forget to like and Mark me

Answer:

Explanation:

The law of multiple proportions.

Answer:

it is 0.50=0.5 M

Explanation:

Molarity definition is measure the concentration of solution.

and the rule is

molarity(M)= moles of solute/volume of solution in liters

Ex: 2.1 M MgCl2= 2.1 mole MgCl2/ L MgCl2 solution

Answer:

18 moles of O2 can be produced by letting 12.00 moles of KClO3 react

Explanation:

The balanced equation is

2KCIO3 ---> 2 KCl + 3 O2

As per the reaction,

2 mole of KClO3 produces 3 mole of O2 gas

Hence, 12 moles of KClO3 will produce [tex]12*\frac{3}{2} =18[/tex]

Hence,   18 moles of O2 can be produced by letting 12.00 moles of KClO3 react

Answer:

ok

Explanation:

1d

2c

3b

4a

Answer:

Wavelength (typically measured in nanometers) is the distance between two points in a wave.Frequency (typically measured in Hertz) is the number of waves in a specific time . Frequency and wavelength have both direct and inverse relationships. The crucial difference between frequency and wavelength is that frequency shows the total number of wave oscillations in a given time. As against wavelength specifies the distance between two specific points of a wave.

Explanation:

Frequency is how often something changes per second be it amplitude of a voltage on a wire or be it the bobbing back and forth of a bobblehead. Frequency is how often something moves up and down in a second. If a bobble head moves forward and backward in one second then it has a bobbling frequency of 1 Hertz (Hz). The unit of frequency is Hertz (Hz) or # of cycles or oscillations per second. A wavelength is measured in distance like meters (m). For photons or light or radiowaves the equation is wavelength=speed of light/frequency.

Answer:

Wavelength (typically measured in nanometers) is the distance between two points in a wave, while frequency is how often something changes per second be it amplitude of a voltage on a wire or be it the bobbing back and forth of a bobblehead.

Answer:

its number 4 D layer 4

Explanation:

just look at it look at the colors so that's how you know and plus it just old

Answer:

From what I gathered from researching, I would say that Layer 2 is the correct answer to the question you asked.

Explanation:

The reason I'd say it is Layer 2 is because the lower you look in a canyon, the farther back you look in time. Over that canyon's history, more layers are added on top of the rock and ground as erosion and weathering happen.

Layer 2 is the highest up, which means that it was added the most recent of the other layers. Although there are more things that could maybe be taken to account, the best answer I see from what information you were given in this question... Layer 2 is the correct answer.

Hope that helps!

Answer:

hydroxide ion

Explanation:

because base produce hydroxide ion when dissolved in water

Answer:

The answer is Color,atomic mass, state of matter of each element.

Explanation:

Answer:

0.0039 mol/L

The molar solubility is 0.0039 mol/L, thus the common ion effect has reduced the solubility from 0.016 mol/L for Ag2SO4 in pure water to 0.0039 mol/L in the Na2SO4 solution.

Explanation:

Answer:

4

Explanation:

From the options provided the result of the error is ( A ) ; The buffer will have a lower capacity because of the smaller number of moles of  HF and F⁻ available to react if an acid or base is added.

Considering the acid ionization equilibrium for the weak acid HF.

A buffer solution is a solution that its PH value remains unchanged when a small amount of acid or base to added to the solution, therefore when the moles of acid or base present in the buffer solution is high enough the buffer solution will have a high buffer capacity. from the mistake of the student the number of moles present is lesser which means that the buffer solution will have a lower capacity

Hence the buffer will have a lower capacity because of the smaller number of moles of HF and F⁻ available to react is an acid or base is added.

learn more : https://brainly.com/question/2131477

Answer:

956 mmHg

Explanation:

The combined gas law states that P1V1/T1 = P2V2/T2 when moles of gas are constant. We're looking for P2, so solve all of that for P2. Make sure you convert your temperatures to Kelvin by adding 273 to the Celsius temperatures.

P2 = P1V1T2/T1V2

P1 = 800.00 mmHg

V1 = 5.0 L

T2 = 100 + 273 = 373 K

T1 = -50 + 273 = 223 K

V2 = 7.0 L

P2 = (800.00 mmHg)(5.0 L)(373 K) / (223 K)(7.0 K) = 956 mmHg

Answer:

D 3.96 10-19J

Explanation:

I took the test