Which statement is true?

1. Heat refers to a process.
2. Thermal energy refers to a process.
3. Thermal energy refers to a single particle.
4. Heat refers to a quantity.

Answer:

0.017g/mol

Explanation:

according to the mole concept to calculate the number of moles of a substance you use the formula

number of moles= mass/molecular mass

=4.5g/254g/mole

=0.017moles

I hope this helps and sorry if it's wrong

Answer:

C

Explanation:

This is because matter is anything that has mass and occupies space.Therefore the space occupied by matter is volume

Answer:

irregular galaxy

pls give brainliest :)

Answer:

irregular galaxy

it is undefined shape

1. Cl2 + H2O → HOCl + HCl

2. Tooth decay starts when when the pH of the mouth is lower than 5.5. Tooth enamel is made up of calcium phosphate and it is one of the hardest substances of the body. But it is corroded when the pH is less than 5.5. The bacteria of our mouth produce acids by degradation of sugar and food particles remaining in our mouth after eating food.

3. Fluorine salts are added in toothpaste to protect our teeth from tooth decay. Fluorine salts are mildly basic, so they neutrelise the acid in our mouth that leads to tooth decay.

4. Tincture of iodine is iodine, pottasium iodide and sodium iodide dissolved in ethanol. Iodine acts in an antiseptic manner by destroying microbial proteins and DNA.

5. Tincture of iodine is clear and reddish brown liquid.

Answer:

C is the correct answer

Explanation:

most probably

Answer:

the activation energy is 65-30

35

The activation energy of this reaction is 35 kJ.

Activation energy, in chemistry, the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo chemical transformation or physical transport.

The activation energy is equal to the difference between the threshold energy needed for the reaction and the average kinetic energy of all the reacting molecules.

The activation energy of a reaction is the difference in energy between the threshold energy and energy of the reactants.

Given,

The highest energy for a reaction to happen = Threshold energy = 65 kJ

Energy of the reactants = 30 kJ

Therefore, The activation energy of this reaction is 35 kJ.

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both electronegativity and ionization energy increase from bottom to top and from left to right

on the periodic table.

Answer:

A

Explanation:

Hydrogen bonds are intermolecular forces of interaction that exist between molecules of a substance in which hydrogen is bonded to a highly electronegative atom. Hydrogen bonds are strong intermolecular forces and account for high melting and boiling points of small molecules such as water. They stem from dipole-dipole interaction between molecules of a substance.

Metallic bonds are bond forces which exist in a metal. Metal cations are held together by a sea of electrons via electrostatic interaction.

The ionic bond is formed by transfer of electrons from one atom to another leading to the formation of an ion pair held together by electrostatic attraction.

Metallic bonds and hydrogen bonds are much weaker than ionic bonds. Ionic compounds are known to have high melting and boiling points.

Answer:

∆H0 = -222kJ/mol

Explanation:

Using Hess's law, we can find the ΔH of a reaction from the sum of another related reactions as follows:

Using the reactions:

(1) C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol

(2) CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol

Twice (1):

2C(s) + 2O2(g) → 2CO2(g) ∆H0= 2*-394 KJ/mol = -788kJ/mol

The inverse reaction of (2):

-(2) CO2(g) → CO(g) + 1/2 O2(g) ∆H0= 283 KJ/mol

Twice this reaction:

2*-(2) 2CO2(g) → 2CO(s) + O2(g) ∆H0= 2*283 KJ/mol= 566kJ/mol

Now, the sum of 2*(1) - 2*(2) produce:

2C(s) + 2O2(g) + 2CO2(g)→ 2CO2(g) + 2CO(g) + O2(g) ∆H0= -788kJ/mol +  566kJ/mol

Subtracting the molecules that ar in both sides of the reaction:

2C(s) + O2(g) → 2CO(g) ∆H0 = -222kJ/mol

Answer:

If you're indoors, stay inside. If you're outside, stay outside. If you're indoors, stand against a wall near the center of the building, stand in a doorway, or crawl under heavy furniture (a desk or table). Stay away from windows and outside doors.

Answer

Answer:

Explanation:

Ammonia = NH3

Oxygen = O2

When these two (2) chemical elements react together, they form two chemical compound which are nitrogen oxide and water.

NH3 + O2 -----> NO + H2O

We would balance the chemical equation like this;

NH3 + 3O2 -----> 4NO + 2H2O

Answer: The volume of 9.7 tons of given ethylene glycol is 0.0079 [tex]m^{3}[/tex].

Explanation:

Given: Density = 1.11 [tex]g/cm^{3}[/tex]

Mass = 9.7 tons

Convert tons into lb as follows.

[tex]1 ton = 2 \times 10^{3} lb\\9.7 ton = 9.7 ton \times 2 \times 10^{3} \frac{lb}{1 ton}\\= 19.4 \times 10^{3} lb[/tex]

Now, lb is converted into kg as follows.

[tex]1 kg = 2.2046 lb\\1 lb = 0.453592 kg\\19.4 \times 10^{3} lb = 19.4 \times 10^{3} lb \times 0.453592 \frac{kg}{1 lb}\\= 8.79 kg[/tex]

1 kg = 1000 g

So, 8.79 kg = 8790 g

Density is the mass of a substance divided by its volume. Hence, volume of ethylene glycol is calculated as follows.

[tex]Density = \frac{mass}{volume}\\1.11 g/cm^{3} = \frac{8790 g}{volume}\\volume = 7918.92 cm^{3} (1 cm^{3} = 10^{-6} m^{3})\\= 0.0079 m^{3}[/tex]

Thus, we can conclude that the volume of 9.7 tons of given ethylene glycol is 0.0079 [tex]m^{3}[/tex].

Answer:

2, 2, 2, 2, 3, 2, 3

Explanation:

The coefficient of the equation (i) CH₄ + O₂ → CO₂ + H₂O are 2, 2 the coefficient of equation (ii) CaCl₂ + AgNO₃ → Ca(NO₃)₂ + AgCl are 2, 2  and the coefficient of equation (iii) C₂H₆O + O₂ → CO₂ + H₂O are 3, 2, 3.

The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.

Here the given equations are

(i) CH₄ + O₂ → CO₂ + H₂O

(ii) CaCl₂ + AgNO₃ → Ca(NO₃)₂ + AgCl

(iii) C₂H₆O + O₂ → CO₂ + H₂O

Now balance the equation (i)

CH₄ + O₂ → CO₂ + H₂O

Reactant side             Product Side

C = 1                              C = 1

H = 4                             H = 2

O = 2                             O = 3

In the reactant side there are 4 H atoms and in product side there are 2 H atoms are present. So multiply by 2 in the product side to balance the H atoms.

CH₄ + O₂ → CO₂ + 2H₂O

Reactant side             Product Side

C = 1                              C = 1

H = 4                             H = 4

O = 2                             O = 4

In the reactant side there are 2 O atoms and in product side there are 4 H atoms are present. So multiply by 2 in the reactant side to balance the O atoms.

CH₄ + 2O₂ → CO₂ + 2H₂O

Reactant side             Product Side

C = 1                              C = 1

H = 4                             H = 4

O = 4                             O = 4

Here we can see that the equation is balanced. The coefficient are 2, 2.

Now balance the equation (ii)

CaCl₂ + AgNO₃ → Ca(NO₃)₂ + AgCl

Reactant side             Product Side

Ca = 1                             Ca = 1

Cl = 2                              Cl = 1

Ag = 1                              Ag = 1

N = 1                                N = 2

O = 3                               O = 6

In the reactant side there are 2 Cl atoms and in product side there is 1 Cl atom is present. So multiply by 2 in the product side to balance the Cl atoms.

CaCl₂ + AgNO₃ → Ca(NO₃)₂ + 2AgCl

Reactant side             Product Side

Ca = 1                             Ca = 1

Cl = 2                              Cl = 2

Ag = 1                              Ag = 2

N = 1                                N = 2

O = 3                               O = 6

In the reactant side there is 1 Ag atom and in product side there are 2 Ag atoms are present. So multiply by 2 in the reactant side to balance the Ag atoms.

CaCl₂ + 2AgNO₃ → Ca(NO₃)₂ + 2AgCl

Reactant side             Product Side

Ca = 1                             Ca = 1

Cl = 2                              Cl = 2

Ag = 2                             Ag = 2

N = 2                               N = 2

O = 6                               O = 6

Here we can see that the equation is balanced. The coefficient are 2, 2.

Now balance the equation (iii)

C₂H₆O + O₂ → CO₂ + H₂O

Reactant side             Product Side

C = 2                              C = 1

H = 6                              H = 2

O = 3                              O = 3

In the reactant side there are 2 C atoms and in product side there is 1 C atom is present. So multiply by 2 in the product side to balance the C atoms.

C₂H₆O + O₂ → 2CO₂ + H₂O

Reactant side             Product Side

C = 2                              C = 2

H = 6                              H = 2

O = 3                              O = 5

In the reactant side there are 6 H atoms and in product side there are 2 H atoms are present. So multiply by 3 in the product side to balance the H atoms.

C₂H₆O + O₂ → 2CO₂ + 3H₂O

Reactant side             Product Side

C = 2                              C = 2

H = 6                              H = 6

O = 3                              O = 7    

In the reactant side there are 3 O atoms and in product side there are 7 H atoms are present. So multiply by 3 in the reactant side to balance the O atoms.

C₂H₆O + 3O₂ → 2CO₂ + 3H₂O

Reactant side             Product Side

C = 2                              C = 2

H = 6                              H = 6

O = 7                              O = 7        

Here we can see that the equation is balanced. The coefficient are 3, 2, 3.

Thus, we can say that the coefficient of the equation (i) CH₄ + O₂ → CO₂ + H₂O are 2, 2 the coefficient of (ii) CaCl₂ + AgNO₃ → Ca(NO₃)₂ + AgCl are 2, 2  and the coefficient of equation (iii) C₂H₆O + O₂ → CO₂ + H₂O are 3, 2, 3.

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D

Explanation:

Particles of the same charge repel each other

Answer:

its D

Explanation:

Took the test

The specie whose concentration is plotted is D. The rate of reaction is how quickly or slowly hat a reaction proceeds.

The term rate of reaction refers to how quickly or slowly hat a reaction proceeds. A reaction rate plot involves the concentration of the species plotted against time.

Now we can see from the plot that concentration is increasing with time. Since the concentration of products increases with time, then the specie whose concentration is plotted is D.

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Answer:

I would

Explanation:

I would support the change to the metric system only because it allows children to understand smaller forms of units and measurements. Also, it will allow people in the math and science fields to broaden their knowledge of equations and formulas. Meaning that the scientist and mathematicians will be able to solve more problems in the world right now.  Overall, the education system for the children of the United States would benefit from the change in the measurement system.

Answer:

1

Explanation:

Ferric Hydroxide

3. 1

Fe. (OH)

Fe(OH)3

Answer:

iron(III) hydroxide

Explanation:

I just took the quiz!

Answer:

15g

Explanation:

First, you need to correct the answer to the previous question. The percentage by mass of Mg in MgO =

Mg = 24.3 amu

O = 16.0 amu

The total mass of MgO = 40.3 amu

To calculate the percent composition of Mg:

% = 24.3/40.3 x 100

% = 60

To calculate the mass of Mg needed to make 25g of MgO:

x/25g = 60%/100%

100x = (25)(60)

100x = 1500

x = 15g

Answer:

The answer is "Auger".

Explanation:

The Auger effect is an effect size when the vacancy of even an atom throughout the inner shell was complemented by the release of even an electron from the same atom. Whenever a central electron is lost, a higher energy level electron can drop into the void and release energy, which can be the result.

Answer:

By using the criss cross method,the -1 charge of nitrate ion is shifted to ammonium ion and +1 charge of ammonium ion is shifted to nitrate ion. In this way, the final formula NH4NO3 is formed for the ammonium nitrate.

Answer:

Although a single organism can survive without reproducing, organisms must reproduce in order to ensure the survival of the species.

Answer:

Answer: They are attracted to each other due to their electrostatic attraction. All that means is the hydrogen atom is positively charged, while the oxygen atom is negatively charged. ... The hydrogen of one water molecule will bond to the oxygen atom of another molecule.

Answer:

They are attracted to each other due to their electrostatic attraction. All that means is the hydrogen atom is positively charged, while the oxygen atom is negatively charged. ... The hydrogen of one water molecule will bond to the oxygen atom of another molecule.

Explanation:

Answer:

A

Explanation:

The instrument in which the washer works as a valve is  A ; syringe

Each instrument listed have a washer and a valve, but of all the instruments listed above the instrument that its washer works also as a valve is the syringe.

A syringe is composed of a thin tube and a thinner hollow needle attached to the end of the thin tube. the needle is used and take in liquids and also expel liquids from the syringe ( i.e. washer and valve )

hence the instrument that its washer also functions as a valve is the syringe.

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Answer:

The Cavendish experiment, performed in 1797–1798 by English scientist Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory and the first to yield accurate values for the gravitational constant

Explanation:

I think that's correct

[tex]option(a)[/tex]

Explanation:

You answer is correct as you move from left to right across a period. But, the question is asked regarding to the right to left across a period. So, as you move from right to left across a period, you can find firstly Non-metals, secondly Metalloids, and lastly Metals.