The validity of scientific theories and laws depends on evidence. Which of the following statements of evidence supports a law rather than a theory?
Electrons orbit the nucleus of an atom within a certain radius.
DNA analysis reveals that a modern species is related to an extinct species.
Seafloor spreading occurs at a rate of three centimeters per year in the mid-Atlantic.
The amount of matter in a closed system is the same at the start of a reaction as at the end of the reaction.

Answer:

1.048x10⁻³M/s is the rate of reaction

Explanation:

Based on the reaction:

2HBr → H₂ + Br₂

The rate of reaction is defined as:

1/2 Δ[HBr] / Δt

1/2 because the reaction is consuming 2 times HBr per mole of reaction

Where Δ[HBr] is 0.550M - 0.506M = 0.044M

And Δt is 21.0s. The average rate of reaction is:

1/2 0.044M / 21.0s =

Answer:

302 kj heat is released by lowering the temperature

302kJ is the amount of heat which is released by lowering the temperature of 825 grams of molten (liquid) lead at 800K to solid lead at 295K. Therefore, the correct option is option C.

Heat is energy that is transmitted from one object to another as a result of a temperature differential. When two bodies of differing temperatures come into contact, energy is transmitted as heat flows first from hotter to the colder.

melting point of lead= 328°C.

T₁ = 328 + 273 = 800K

T₂ = 295K

T₃ = 600.61K

latent head of fusion of lead = 4.8 kJ/mol

specific heat of solid lead= 0.13 J/g/K

specific heat of liquid lead = 0.14 J/g/K

heat= mS∆T + (m/M)Lf + mS∆T'

= 23g × 0.13 J/g/K × (601 - 297)K + 23g/207g/mol × 4.8 kJ/mol + 23g × 0.14 J/g/K × (702 - 601)K

=302kJ

Therefore, the correct option is option C.

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Answer:

C. 10 W.

Explanation:

Hello!

In this case, since the power the person uses to lift the 10-N load is computed by using the formula:

[tex]P=\frac{W}{t}[/tex]

Whereas W is the work and t the time; we can compute the work by multiplying the force applied in 1 m:

[tex]W=10N*1m=10J[/tex]

Now, we divide it by the time to obtain:

[tex]P=\frac{10J}{1s}=10W[/tex]

Since joules over seconds are watts.

Best regards!

Terri and Ernesto should both use geographic maps.

may i have brainliest? :D

Answer:

C.

Explanation:

I dunno. took the test and got it right.

Answer:The majority of chemical processes are reactions that occur in solution. Important industrial processes often utilize solution chemistry. "Life" is the sum of a series of complex processes occurring in solution. Air, tap water, tincture of iodine, beverages, and household ammonia are common examples of solutions.

A solution is a homogenous mixture of substances with variable composition. The substance present in the major proportion is called the solvent, whereas the substance present in the minor proportion is called the solute. It is possible to have solutions composed of several solutes. The process of a solute dissolving in a solute is called dissolution.

Explanation:

Answer:

a.

[tex]M_{CaBr_2}=40.08+79.9*2=199.88 g/mol[/tex]

b.

[tex]M_{BeBr_2}=9.012+79.9*2=168.81g/mol[/tex]

c.

[tex]M_{CdBr_2}=112.41+79.9*2=272.21g/mol[/tex]

d.

[tex]M_{CuBr_2}=63.55+79.9*2=223.35g/mol[/tex]

Explanation:

Hello!

In this case, since the molar mass of a compound is computed by adding the molar mass of each element composing it and multiplying it by the number of atoms in the molecule, we have:

a.

[tex]M_{CaBr_2}=40.08+79.9*2=199.88 g/mol[/tex]

b.

[tex]M_{BeBr_2}=9.012+79.9*2=168.81g/mol[/tex]

c.

[tex]M_{CdBr_2}=112.41+79.9*2=272.21g/mol[/tex]

d.

[tex]M_{CuBr_2}=63.55+79.9*2=223.35g/mol[/tex]

Best regards!

Answer:

Specific heat capacity of copper is 0.385 J/g.°C

Explanation:

Given data:

Specific heat capacity of copper = ?

Heat absorbed by copper = 57.8 J

Mass of copper = 10 g

Temperature changes = 15°C

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

by putting values

57.8 J = 10 g × c × 15°C

57.8 J = 150 g.°C × c

c = 57.8 J / 150 g.°C

c = 0.385 J/g.°C

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Specific heat capacity of copper is 0.385 J/g.°C.

Answer:

4.17e+22 atoms of tin are present in the cube

Explanation:

We don't require the size of the cube. With the mass and the molar mass of tin = 118.7 amu we can find moles of Tin. As 1 mol = 6.022x10²³ atoms we can find the number of atoms:

Moles Tin:

8.21g * (1mol / 118.7g) = 0.0692 moles Tin

Atoms Tin:

0.0692 moles Tin * (6.022x10²³ atoms / mol) =

Answer:

answer: Weight is a 'force' and in the imperial system, it is measured in pounds-force (lbf or lbf). You might hear this term used together with the term 'slug'. A slug has a mass of 32.174049 lb. Explanation:

Explanation:

The unit pound is a unit of mass which is from the British imperial units of measurements. Pound is not included in CGS or SI units of mass.

Mass of a substance is its total amount which can be expressed in any units such as g, Kg etc. Our mass is affected by the gravity and thus the total weight of a body is mass multiplied by gravity.

There are different system for units and each units of a measurement is interrelated. Units are very significant in measurements and to identify the variables.

The most commonly used unit system is international system of units called the SI system. Where the mass length and time are in Kg, m and seconds. In CGS system it is gram, meter and seconds.

Pound is unit of mass from imperial unit system of britain. One pound = 0.4533 Kg.

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Answer:

(2)

Explanation:

Answer:

7 is answer.

Explanation:

therefore, the mass number of an atom with 3 protons,4 neutrons,and 3 electrons is 7.

I hope it's helpful!

Answer: Avogrado's Constant

Explanation:

One mole of a substance is equal to 6.022 × 10²³ units of that substance (such as atoms, molecules, or ions). The number 6.022 × 10²³ is known as Avogadro's number or Avogadro's constant. The concept of the mole can be used to convert between mass and number of particles.

Answer:

potassium chloride (KCl)

Explanation:

The reaction between aqueous potassium hydroxide and aqueous iron (III) hydroxide is a double replacement reaction.

3 KOH + FeCl₃ → 3 KCl + Fe(OH)₃

Hope that helps.

Answer:

The correct answer is

[tex]Fe(OH)_{3}[/tex]

Explanation: I tried the KCI and it was incorrect but it showed the answer so here you go!

Answer:

D= 109.5 degrees, 109.5 degrees, 120 degrees

Explanation:

The bond angle observed for any bond between two chemical species depends on the hybridization of the atoms.

However, for organic compounds, single bonds normally involve sp3 hybridized atoms with a bond angle of 109.5 degrees such as in the positions marked a and b.

However, a double bond is made of atoms in sp2 hybridized state with a bond angle of 120 degrees such as in c.

Answer:

3,2,1,6

2,3,3,2

Explanation:

HOPE THIS HELPED

The balls of the Newton’s cradle eventually stop because they loose energy as they collide.

The balls of the Newton’s cradle lose energy to the air as they move through it due to friction.

These balls make sound when they collide, and consequently the balls loose energy to heat upon collision.

The balls loose energy as they collide with each other and eventually stop.

Thus, we can conclude that the balls of the Newton’s cradle eventually stop because they loose energy as they collide.

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Answer:

The new pressure is 1,135.67 torr

Explanation:

Boyle's law establishes the relationship between pressure and volume of a gas when the temperature is constant, establishing that the pressure of a gas in a closed container is inversely proportional to the volume of the container. Mathematically, this law says that the product of pressure and volume is constant:

P*V=k

Charles's law establishes the relationship between the temperature and the volume of a gas when the pressure is constant. This law states that the volume is directly proportional to the temperature of the gas. So, Charles's law says that the quotient that exists between the volume and the temperature will always have the same value:

[tex]\frac{V}{T} =k[/tex]

Finally, Gay-Lussac's Law is a gas law that relates pressure and temperature at constant volume. This law says that the pressure of the gas is directly proportional to its temperature:

[tex]\frac{P}{T} =k[/tex]

Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:

[tex]\frac{P*V}{T} =k[/tex]

Analyzing an initial state 1 and a final state 2, it is satisfied:

[tex]\frac{P1*V1}{T1} =\frac{P2*V2}{T2}[/tex]

In this case:

Replacing:

[tex]\frac{662 torr*46.7 L}{266 K} =\frac{P2*35 L}{342 K}[/tex]

Solving:

[tex]P2=\frac{342 K}{35 L} *\frac{662 torr*46.7 L}{266 K}[/tex]

P2= 1,135.67 torr

The new pressure is 1,135.67 torr

Answer:

700N

Explanation:

F=ma

mass=35

acceleration =20

Answer:

a. 0.80 m³/kg

b. 0.67 m³/kg

Explanation:

a.

Step 1: Given data

Volume of the container (V): 20 m³

Mass of methane (m): 25 kg

Step 2: Calculate the specific volume (v) of methane

Specific volume is defined as the number of cubic meters occupied by one kilogram of matter.

v = V/m

v = 20 m³/25 kg = 0.80 m³/kg

b.

Step 1: Calculate the mass of the mixture

m = m(methane) + m(ethane)

m = 25 kg + 5 kg = 30 kg

Step 2: Calculate the specific volume (v) of the mixture

v = V/m

v = 20 m³/30 kg = 0.67 m³/kg

Answer:

85 ml

Explanation:

move the decimal place over two times

Answer:

The 91.8% is present as bicarbonate ion

Explanation:

It is possible to find pH of a buffer using H-H equation:

pH = pKa + log [A⁻] / [HA]

Where pH is 7.40; pKa is 6.36, [A⁻] is concentration of bicarbonate ion and [HA] concentration of carbonic acid

7.40 = 6.35 + log [A⁻] / [HA]

1.05 = log [A⁻] / [HA]

11.22 = [A⁻] / [HA] (1)

As the question is in therms of percentage:

[A⁻] + [HA] = 100 (2)

Replacing (2) in (1):

11.22 = [A⁻] / 100 - [A⁻]

1122 - 11.22[A⁻] = [A⁻]

1122 = 12.22[A⁻]

91,8% = [A⁻]

Answer:

Empirical formula is C₄H₁₀O

Explanation:

Values for C, H and O are determined as centesimal composition.

64.80 g of C in 100g of compound

13.62g of H in 100 g of compound

21.58 g of O in 100 g of compound.

We convert the mass to moles:

64.80 g . 1mol/ 12g = 5.4 moles of C

13.62 g . 1 mol /1g = 13.62 moles of H

21.58 g . 1 mol/16g = 1.35 moles of O

We pick the lowest value and we divide:

5.4 moles of C / 1.35 = 4 C

13.62 moles of H / 1.35 = 10 H

1.35 moles of O / 1.35 = 1 O

Empirical formula is C₄H₁₀O, it can be the diethyl ether.

We confirm, the excersise is well done.

Molar mass = 74g/mol

74 g of compound we have (12 . 4)g of C

In 100 g of compound we may have (100 . 48) / 74 = 64.8 g

Answer:

[tex]m=1,182.8g[/tex]

Explanation:

Hello!

In this case, since the relationship between molecules and mass is first analyzed via the Avogadro's number to compute the moles in the given molecules:

[tex]mol=4.63x10^{24}molec*\frac{1mol}{6.022x10^{23}molec}=7.69mol[/tex]

We now use the molar mass of carbon tetrachloride (153.81 g/mol) to obtain the required grams:

[tex]m=7.69mol*\frac{153.81g}{1mol} \\\\m=1,182.8g[/tex]

Best regards!

Answer:

Mass = 21.24 g

Explanation:

Given data:

Number of moles of ammonia = 7.08 mol

Mass of hydrogen reacted = ?

Solution:

Chemical equation:

3H₂ + N₂      →    2NH₃

Now we will compare the moles of ammonia and hydrogen.

             NH₃        :         H₂  

              2           :         3

          7.08         :        3/2×7.08 = 10.62

Mass of hydrogen:

Mass = number of moles × molar mass

Mass = 10.62 mol × 2 g/mol

Mass = 21.24 g

Answer:

See explanation

Explanation:

Average heart beat = Number of heart beats/ time

7.0 years = 7.0 * 365 * 24 * 60 = 3679200 minutes

If there are 69 beats in 1 minutes

There are x beats in 3679200 minutes

x = 253865 beats

x = 254000.00 beats ( to 3 sf)

beats in 7.00 years = 254000.000 beats

beats in 7.000 years = 254000.0000 beats

Answer:

The factors are various, although there are main and accessories.

The main factor is the climate of the area, that is, if it is a rainier climate, there will be more water masses in the lands where this climate abounds (usually it is wet).

Other factors are: geographical features, flows, the path of rivers, lakes or lagoons, the presence or absence of ports, the number of trees and the distribution of rocks.

Explanation:

Another important factor is the height of the land, the higher the level of the earth, the more difficult it will be to accumulate water, this is how low areas are also flooded.

Answer:

1. B

2. A

3. E

4. D

5. C

Explanation:

Answer:

Barium chloride is represented as BaCl2.

Explanation:

so answer is a.)2

I hope it's helpful!

Answer: Fluorine

Explanation: Fluorine has an oxidation state of -1, meaning it gains 1 electron in chemical bonds, forming a negative ion. Magnesium has an oxidation state of +2, nitrogen has -3, and lithium has an oxidation state of +1.

Answer:

Fluorine.

Explanation:

I took this test not to long ago. I got this question correct. Also, the reason is because every other element is balanced.