which two quantities are used to predict gravitational force according to Newton's law of universal gravitation a. mass and speed b. mass and distance c. distance and velocity d. velocity and mass

Answer: Some examples are color, density, volume and mass

Explanation:

Physical properties are anything you can smell, touch, or hear. They can be observed without changing.

Explanation:

A number can be written in the form of scientific notation as follows :

[tex]N=x\times 10^y[/tex]

x is any real number and y is integer

(a) The distance between Pluto and the Sun is 5,913,000 km.

There are 6 digits after 5. In scientific form is given by :

[tex]N=5.91\times 10^6\ km[/tex]

(b) The density of nitrogen gas is 0.0012506 g/cm³.

There are 2 digits before 1. In scientific notation,

[tex]d=1.25\times 10^{-3}\ g/cm^3[/tex]

Answer:

The answer is

Explanation:

To find the number of moles in a substance when given the molar mass and mass we use the formula

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

where

n is the number of moles

M is the molar mass

m is the mass of the substance

Mr( Na) = 23 , Mr( CL ) = 35.5

Molar mass ( NaCl ) = 23 + 35.5

= 58.5 g/mol

Mass = 1.005 kg

It's equivalent in grams is

1.005 × 1000 = 1005 g NaCl

So the number of moles in NaCl is

[tex]n = \frac{1005}{58.5} \\ = 17.179487...[/tex]

We have the final answer as

17.2 mol to the nearest tenth

Hope this helps you

Answer:

The correct option is C

Explanation:

From the question we are told that

The reaction is

[tex]C_{16}H_{32}O_2(g) + 23O_2(g) \to 16 CO_2(g) + 16 H_2O(l)[/tex]

Generally [tex]\Delta H = \Delta U + \Delta N* RT[/tex]

Here [tex]\Delta H[/tex] is the change in enthalpy

[tex]\Delta U [/tex] is the change in the internal energy

              [tex] \Delta N[/tex]  is the difference between that number of moles of product and the number of moles of reactant

Looking at the reaction we can discover that the elements that was consumed and the element that was formed is [tex] O_2[/tex] and  [tex]CO_2[/tex] and this are both gases so the change would occur in the number of moles

So  

[tex]\Delta H = \Delta U + [16 -23]* RT[/tex]

[tex]\Delta H = \Delta U -7RT[/tex]

The  negative sign in the equation tell us that the enthalpy[tex]\Delta_r H[/tex] would be less than the Internal energy [tex]\Delta_r U[/tex]

The answer is 30.

Explanation:

The total number of protons and neutrons in a nucleus is called mass number. So 14 proton plus 16 neutron is = 30 mass number.

Answer:

it’s electron configuration is 1s^2 2s^2 2p^4. To determine valence electrons, add the outermost s and p orbitals. In an oxygen atom, 8 electrons are present. Electron present in the first shell (n=1) 2n^2=2 (1)^2=2 (1)=2.

Answer:

THE HEAT NEEDED TO CHANGE 3KG OF WATER FROM 10 C TO 80 C IS 877.8kJ OR 877,800 J.

Explanation:

Mass = 3.0 kg = 3 * 1000 = 3000 g

Initial temperature = 10 C

Final temperature = 80 C

Change in temperature = 80 - 10 = 70 C

Specific heat of water = 4.18 J/g C

Heat needed = unknown

Heat is the amount of energy in joules needed to change a gram of water by 1 C.

Heat = mass * specific heat * change in temperature

Heat = 3000 g * 4.18 J/g C * 70 C

Heat = 877 800 Joules

Heat = 877.8 kJ.

The heat needed to change 3 kg mass of water from 10 C to 80 C is 877,800 J or 877.8 kJ.

Answer:

HEPES.

Explanation:

Hello,

In this case, considering the given options, and the pH requirement of 7.5, considering the Henderson-Hasselbach equation:

[tex]pH=pKa+log(\frac{[base]}{[acid]})[/tex]

The best buffer is that having the closest pKa to the required pH, thus, for the given Ka, we obtain:

[tex]pKa_{MES}=-log(Ka_{MES})=-log(7.9x10^{-7})=6.10\\\\pKa_{HEPES}=-log(Ka_{HEPES})=-log(3.2x10^{-8})=7.49\\\\pKa_{Formic \ acid}=-log(Ka_{Formic \ acid})=-log(1.8x10^{-4})=3.74\\\\pKa_{Acetic\ acid}=-log(Ka_{Acetic\ acid})=-log(1.8x10^{-5})=4.74\\\\pKa_{Tris}=-log(Ka_{Tris})=-log(6.3x10^{-9})=8.2[/tex]

Therefore, the best buffer is the HEPES since its pKa is almost the required pH.

Regards-

Answer:

2 mL

Explanation:

Step 1: Given data

Step 2: Calculate the volume of the 10 M solution

We want to prepare a diluted solution from a concentrated one. we can calculate the volume of the initial solution using the dilution rule.

C₁ × V₁ = C₂ × V₂

V₁ = C₂ × V₂/C₁

V₁ = 0.1 M × 200 mL/10 M

V₁ = 2 mL

Answer:

Density =M/V

1500/7600

5.0666666667=Ans...

Answer:

0.31 mole

Explanation:

The following data were obtained from the question:

Mass of SF6 = 45.0 g

Number of mole of SF6 =..?

Next, we shall determine the molar mass of SF6.

This can be obtained as follow:

Molar mass of SF6 = 32 + (19×6)

Molar mass of SF6 = 32 + 114

Molar mass of SF6 = 146 g/mol

Finally, we shall determine the number of mole in 45 g of SF6 as follow:

Molar mass of SF6 = 146 g/mol

Mass of SF6 = 45.0 g

Number of mole of SF6 =..?

Number of mole = mass /Molar mass

Number of mole of SF6 = 45 /146

Number of mole of SF6 = 0.31 mol

Therefore, 0.31 mol is present in 45 g of SF6.

Answer:

See explanation

Explanation:

The slope of a graph in which mass was plotted against volume is the density of the object. Density of objects have been measured and recorded in standard handbooks for the purpose of reference. If the density of an unknown substance is measured, it can now be compared with the density of known substances recorded in standard handbooks such as the handbook of physics and chemistry. By so doing, the unknown substance can be identified.

According to standard handbooks, the density of copper is 8.96 g/ml while that of nickel is 8.908 g/ml. If the average slope obtained is around 8.96 g/ml, then the metal is copper and not nickel.

An alternative to this method is to measure the refractive index of the piece of metal and compare the average values observed with the contents of standard handbooks in order to identify the unknown metal.

Answer:

Explanation:

H ₂ S O ₄ + 2 N a O H ⟶ 2 H ₂ O + N a ₂ S O ₄

29.09 mL of 0.639 M N a O H is mixed with 213.8 mL of H ₂ S O ₄

Let the concentration of H ₂ S O ₄ be S₂ .

In terms of normal or equivalent solution is will be 2 N  solution

From the formula S₁ V₁ = S₂ V₂

= 29.09 x .639 = 213.8 x  S₂

S₂ = .087 N solution

In terms of molar solution it will be .087 / 2 M

= .0435 M

Answer:

Explanation:

The structural formula provides more information which is often used to represent a particular organic substance. A structural formula indicates how the atoms are arranged within the molecule of a substance. From the information, the structure of  4-methyl-5-oxohexanal is represented by using a stick formula where the methyl group falls into position 4 and oxygen group falls into position 5 on the hexanal compound.

The structure is provided in the image attached below for better understanding.

Answer:

Explanation: Mendeleev arranged the elements on the basis of their atomic mass. Melting and boiling point were used as the physical characteristics in deciding the position of elements. He arranged the elements and wrote the formula of their oxides and hydrides which seemed to possess same chemical formula.

Explanation:

Answer:

The limiting reactant is CH₄

26.0g of CH₂Cl₂ is the maximum amount that can be formed

4.15g CCl₄ will remain

Explanation:

The reaction of methane, CH₄, with carbon tetrachloride, CCl₄ is:

CH₄ + CCl₄ → 2CH₂Cl₂

To find the maximum mass of dichloromethane that can be determined we need to find moles of methane and carbon tetrachloride:

Moles CH₄:

2.45g * (1mol / 16.04g) = 0.153 moles

Moles CCl₄:

27.7g * (1mol / 153.82g) = 0.180 moles

That means just 0.153 moles of CCl₄ will react until CH₄ is over.

The limiting reactant is CH₄

Assuming the whole 0.153 moles will react, the moles of CH₂Cl₂ will be:

0.153 moles CH₄ * (2 moles CH₂Cl₂ / 1 mole CH₄) = 0.306 moles of CH₂Cl₂

The mass is (Molar mass dichloromethane: 84.93g/mol):

0.306 moles of CH₂Cl₂  * (84.93g / mol) = 26.0g of CH₂Cl₂

The moles of CCl₄ that remain are:

0.180 moles - 0.153 moles = 0.027 moles

In grams:

0.027 moles * (153.82g / mol) = 4.15g CCl₄

Answer:

The mass of the acetic acid is 13.5 g

Explanation:

Given;

weight percent of the acetic acid (ratio of solute to total solution), w/w = 98 %

volume of acetic acid, v = 12.83 mL

density of acetic acid, ρ = 1.05 g/mL

density is given by;

density = mass / volume

mass = density x volume

mass of the acetic acid in 12.83 mL =  1.05 g/mL x 12.83 mL

mass of the acetic acid in 12.83 mL = 13.5 g

Therefore, the mass of the acetic acid is 13.5 g

≈ 0,27 g/cm³

36.5 l = 36.5 dm³ = 36500 cm³

10 kg = 10000 g

d = m/V

= 10000g/36500cm³

≈ 0,27 g/cm³

Given :

2.5 mole of Sulfuric acid [tex]( H_2SO_4 )[/tex] .

To Find :

Mass of sodium hydroxide will completely neutralize 2.5 mol of sulfuric acid

Solution :

Let us assume volume of water be 1 L .

Now , we know , to neutralize 1 mole of sulfuric acid we need 2 moles of NaOH .

So , for 2.5 mole sulfuric acid required 5 mole of NaOH .

Moles of NaOH ,

[tex]n=M\times Volume \\\\n=5\times 1=5\ moles[/tex]  

Molecular mass of NaOH , M.M = 58.44 g/mol .

Mass of 5 moles of NaOH :

[tex]m=5\times 58.44\ g\\\\m=292.2\ g[/tex]

Hence , this is the required solution .

Answer:

A. When a liquid is first placed in a closed container, the evaporation rate is higher than it is in an open container under the same conditions.

Explanation:

Evaporation refers to the process by which a liquid changes to gas or vapor. It usually occurs at the surface of a liquid.

Factors that affects evaporation include; nature of the liquid, surface area of liquid exposed, temperature and wind.

Considering the options given:

A. When a liquid is first placed in a closed container, the evaporation rate is higher than it is in an open container under the same conditions. = False

This is false because, the more the surface of the liquid exposed, the higher the rate of evaporation.

B. When a liquid is first placed in a closed container, the evaporation rate is higher than the condensation rate. = True

This is true because when a liquid is first placed in a container, the equilibrium position favors evaporation initially than condensation as saturation of the space above the liquid with vapor has not been achieved.

C. When the rates of evaporation and condensation are equal, the system has reached dynamic equilibrium.= True

Dynamic equilibrium is achieved when the rate of forward and backward reaction, in this case, evaporation and condensation are equal.

D. Vapor pressure refers to the pressure of a gas at a given temperature in equilibrium with its liquid phase. = True

E. Stronger intermolecular forces within the liquid typically result in a lower vapor pressure under a given set of conditions.  = True

Strong intermolecular forces between the molecules of the liquid causes the liquid to remain in the liquid state rather than turning to vapor, thereby lowering vapor pressure

Answer:

7. Why is the d-block one energy level behind the s-block? Also, why would the f-block be so far behind?

me to

Explanation:

Answer:

142 ft² (Approx)

Given:

Use feet as measurement device( Approx a foot long)

10.5’ × 13.5’ = 141.75 ft²

Find:

Best area for room

Explanation:

We know that Philip uses his feet to measures the area of the room which is not a proper unit of measurement, so we will take Philip's measurement to the maximum absolute unit

So,

Area of the room = 142 ft² (Approx)

The correct answer is From different social and ethnic backgrounds.

Explanation:

The purpose of science studies is to gain an understanding of specific phenomena and use this in the benefit of the world or humanity. Moreover, science is guided by objective methods and these are applied all around the world. This feature allows scientists from all kinds of social and ethnic backgrounds to study the same phenomena and obtain similar results, which is essential for the progress of scientific knowledge. This is exemplified by two different labs in two different countries studying drug absorption because the results of these two studies can be analyzed together to understand drug absorption.

In this context, one factor that contributes to the progress of scientific knowledge is the effort of scientists "from different social and ethnic backgrounds".

Answer:

The correct answer is From different social and ethnic backgrounds.

Explanation:

right on EDGE 2021

Answer:

All of these are true.

Explanation:

Copper lies below iron in the activity series, this implies that copper is more easily reduced than iron as its electrode potential is positive.

Also, copper is extracted easily from its sulphide ore by oxidation with oxygen. Similarly, the reduction of iron in a blast furnace requires toxic CO, hence the answer above.

Answer:

obtain something from (a specified source).

Explanation:

Answer:

It is like the orgins of something

Answer:

The concentration of dye in solution C is 3.02 M.

Explanation:

To find the concentration of dye in solution C we need to use the following equation:

[tex] V_{1}C_{1} = V_{2}C_{2} [/tex]

Where V is for volume and C is for concentration

In the first dilution we have:

[tex] V_{A}C_{A} = V_{T}C_{B} [/tex]

[tex] 2 mL*23.5 M = (2 mL + 12 mL)*C_{B} [/tex]                              

[tex] C_{B} = 3.36 M [/tex]

Now, in the second dilution:

[tex] V_{B}C_{B} = V_{T}C_{C} [/tex]

[tex] 9 mL*3.36 M = (9 mL + 1 mL)*C_{C} [/tex]  

[tex] C_{C} = 3.02 M [/tex]                        

Therefore, the concentration of dye in solution C is 3.02 M.

I hope it helps you!