what variables effect whether or not the fishing weight floats

Answer:

The necklace is fake.

The necklace is made up of copper.

Explanation:

The following data were obtained from the question:

Mass of the necklace = 21.3 g

Volume of water = 5 mL

Volume of water + Necklace = 7.4 mL

To identify the composition of the necklace, we shall determine the density of the necklace.

This can be obtained as follow:

We'll begin by calculating the volume of the necklace. This can be obtained as shown below:

Volume of water = 5 mL

Volume of water + Necklace = 7.4 mL

Volume of Necklace =.?

Volume of Necklace = (Volume of water + Necklace) – (Volume of water)

Volume of Necklace = 7.4 – 5

Volume of Necklace = 2.4 mL

NOTE:

1 mL = 1 cm³

Therefore,

Volume of Necklace = 2.4 mL = 2.4 cm³

Finally, we shall determine the density of the necklace as follow:

Mass of the Necklace = 21.3 g

Volume of Necklace = 2.4 cm³

Density of Necklace =?

Density = mass /volume

Density = 21.3 / 2.4

Density = 8.87 g/cm³

Therefore, the density of the necklace is 8.87 g/cm³.

From the question given above, we were told Jacy bought a gold necklace.

But comparing the density of necklace to the densities given above the necklace is obviously made of copper material.

Therefore, Jacy bought a fake gold necklace.

Answer:

1.  31.25 mL

2.  1.98 g/L

3.  0.45 g/mL

Explanation:

For each of the problems, you need to perform unit conversions.  You need to use the information given to you to convert to a specific unit.

1.  You need volume (mL).  You have density (g/mL) and mass (g).  Divide mass by density.  You will cancel out mL and be left with g.

(50.0 g)/(1.60 g/mL) = 31.25 mL

2.  You are given grams and liters.  You need to find density with units g/L.  This means that you have to divide grams by liters.

(0.891 g)/(0.450 L) = 1.98 g/L

3.  You have to find density again but this time with units g/mL.  Divide the given mass by the volume.

(10.0 g)/(22.0 mL) = 0.45 g/mL

Answer:

Density of 40 mL of liquid that has a mass of 20 g = 20 / 40 = 0.5 g / cc

Answer:

Density= mass/volume

Density= 20/40

Density= 0.5g/mL

A description of an exothermic reaction is it releases heat. The correct option is A.

An exothermic reaction is a reaction in which heat is released into the atmosphere. In these reactions, less energy is needed to start the reaction and the energy is released when bonds are made in the products. Delta H is always negative in these reactions.

Energy is always given off when the reaction happened, in the form of heat and light. Examples are burning of wood, melting of ice, combustion, corrosion, etc.

Thus, the correct option is A. releases heat regarding a description of an exothermic reaction.

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Answer:

This question appears to be incomplete

Explanation:

However, we know that one of the kinetic theories of gases is that gas molecules collide with one another and against the walls of the container (in which they are stored); hence exerting there pressure on the walls of this container.

Ideal gases are the most suitable for this theory because it's molecules are far apart and do not exert any attractive forces towards one another; hence it's molecules move "undisturbed" or "freely". For ideal gases, the average pressure exerted by by the gas molecules on the walls of the container can be calculated as

PV = nRT

Where P = pressure (in atmosphere, atm or kilopascal, KPa or millimeter mercury, mmHg)

V = volume (in liters)

n = number of molecules

R = ideal gas constant (8.3145 J·mol⁻¹·K⁻¹)

T = temperature (in kelvin)

Answer:

a. the kinetic energy will be the same.

b. [tex]\mathbf{\overline v = 407.65 \ m/s}[/tex]

Explanation:

The kinetic theory deals with how the arrangement of particles of a substance determines the properties that substance will possess and the state in which it is likely to be found under a given set of conditions. From the postulates of the kinetic theory of gases, The average kinetic energy of the gas molecules is a measure of the temperature of the gas molecules, This implies that the kinetic energy is dependent on the temperature.

i.e

[tex]K.E = \dfrac{3}{2} \ KT[/tex]

where ;

K = Boltzmann Constant

Since the given gases are in thermal equilibrium, therefore, the kinetic energy will be the same.

b).

The root mean square velocity of CO2 molecule is represented by the equation :

[tex]\overline v = \sqrt{\dfrac{3RT}{M_m}}[/tex]

[tex]\overline v = \sqrt{\dfrac{3\times 8.314 \ J/K /mole \times (293.15 \ K ) }{44 \times 10^{-3} \ kg / mol}}[/tex]

[tex]\overline v = \sqrt{\dfrac{7311.7473 }{44 \times 10^{-3} }}[/tex]

[tex]\overline v = \sqrt{166176.075 \ m/s}[/tex]

[tex]\mathbf{\overline v = 407.65 \ m/s}[/tex]

Answer:

The total mass of the reactants equals the total mass of the products.

Explanation:

The true statement for all chemical reactions is that the total mass of the reactants equals the total mass of the products.

Chemical reactions are those reactions in which reactants react with each other and converted into products for the completion of the reaction.

Let us assume a chemical reaction:

A + B → C + D

Where, A & B are reactants which are converted into products C & D. Means mass of reactants will convert into the mass of products as it follows the law of conservation of mass.

So, total mass of the reactants equals the total mass of the products.

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Answer:

A ; 20g of water has the least number of molecules

Explanation:

Here, we want to know which of the options represent the least number of molecules;

To calculate this, we are going to first calculate the number of moles using the formula below;

Number of moles = mass/molar mass

Then from the number of moles, we can calculate the number of molecules by multiplying the number of moles by 6.02 * 10^23 molecules

Let’s proceed;

a. That will be 20/18.02 = 1.1099 moles

1.1099 * 6.02 * 10^23 = 6.68 * 10^23 molecules

b. That will be 77/16.06 = 4.8 moles

4.8 * 6.02 * 10^23 = 2.89 * 10*24 molecules

c. That will be 68/42.09 = 1.62 moles

1.62 * 6.02 * 10^23 = 9.73 * 10^23 molecules

d. That will be 100/44.02 = 2.27 moles

2.27 * 6.02 * 10^23 = 1.37 * 10^24 molecules

e. That will be = 84/20.01 = 4.2 moles

4.2 * 6.02 * 10^23 = 2.53 * 10^24 molecules

From all the values obtained, the lowest is 20g of water

Answer:

Because both CaCl2 and CaBr2 both contain elements (Chlorine and Bromine) from the same group (group 7)

Explanation:

Elements are placed into different groups in the periodic table. Elements in the same group are those that have the same number of valence electrons in their outermost shell and as a result will behave similar chemically i.e. will react with other elements in the same manner.

Chlorine and Bromine are two elements belonging to group 7 of the periodic table. They are called HALOGENS and they have seven valence electrons in their outermost shell. Hence, when they form a compound with Calcium, a group two element, these compounds (CaCl2 and CaBr2) will possess similar properties because they have elements that are from the same group (halogen group).

The compounds of [tex]\rm CaCl_2[/tex] and [tex]\rm CaBr_2[/tex] have similar chemical properties as they are constituted of elements belonging to the same group.

The compounds with the elements belonging to the same group have similar chemical properties. It has been given that the chemical properties of elements have been dependent on the number of valence electrons.

The given compounds have been calcium chloride and calcium bromide. The calcium has been the same cation in the compounds however, the anions are different.

The anion Cl and Br both belongs to group 17 and have 7 valence electrons. Thus, the compounds have been possessing similar chemical properties.

Thus, calcium chloride and calcium bromide are more likely to have similar chemical properties as they have elements belonging to the same group.

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Complete Question

Which is most reactive toward electrophilic aromatic substitution?

A  Phenol

B  Anisole

C  Nitro-benzene

D  Benzene

Answer:

The correct option is  A

Explanation:

Generally the rate at which electrophilic aromatic substitution reaction occur is dependent on the nucleophilicity(nucleophile strength  ) of Benzene ring.Now a functional group  which increase the electron density in the benzene ring when attached to it increases its  nucleophilicity and this in-turn will increase the rate at which electrophilic aromatic substitution reaction occur

Now   Phenol is a compound that is made up of  OH functional group and then the benzene ring

    Anisole is a compound that is made up of  [tex]OCH_3[/tex] functional group and then the benzene ring

    Nitro-benzene is a compound that is made up of  [tex]NO_2[/tex] functional group and then the benzene ring  

Now since OH is the highest In series of activating group compared to the activation groups we are considering (i.e  [tex]OCH_3[/tex]  and [tex]NO_2[/tex] )

Then  Phenol is the answer

Answer:

0.024951344877489 mole.

Explanation:

y

Answer:

750g of Aluminum

Assuming 8.6 cm lenth is the height of the cylinder. The volume of a cylinder is: V = [tex]\pi[/tex]*r^2*h

V = 3.14cm x 10.24cm x 3.6cm

V = 280cm^3

Now density = mass/volume

2.7g/cm^3 = mass/280cm^3

2.7g/cm^3 x 280cm^3 = mass/280cm^3 x 280cm^3

= 750g of Aluminum

Answer:

2.6 kJ/mol

Explanation:

Step 1: Given data

Step 2: Calculate ΔG°

We can calculate ΔG° using the following expression.

ΔG° = ΔH° - T × ΔS°

ΔG° = 40.7 kJ/mol - 350 K × 0.109 kJ/mol.K

ΔG° = 2.6 kJ/mol

The change in Gibbs free energy, ΔG for the water is 2.55 KJ/mol

From the question given above, the following data were obtained:

The Gibbs free energy, ΔG° can be obtained as illustrated below:

ΔG° = ΔH° – TΔS°

ΔG° = 40.7 – (350 × 0.109)

ΔG° = 40.7 – 38.15

ΔG° = 2.55 KJ/mol

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