Which situation describes a chemical change?
A. Clay pressed into a mold takes on the shape of the mold.
B. Baking soda added to vinegar gives off carbon dioxide gas.
C. Chocolate changes from a solid to a liquid when heated.
D. Rubbing pencil lead onto paper changes the color of the paper.

Answers

Answer 1

Answer:

C

Explanation:

I just took the test

Answer 2

Answer:

B

Explanation:


Related Questions


1. Define matter.
2. Compare and contrast length, mass, and volume.
3. What are the three states of matter? Name at least three phase changes.
4. What are the base metric units for:
a. Length
b. Volume
c. Mass
d. Temperature
5. What is the equation used to find density?
6. List the different groups on the periodic table
7. Contrast metals and nonmetals.
8. Draw and label a picture of an atom which includes:
a. Neutrons
b. Protons
c. Electrons
9. Where are the protons and neutrons found in an atom?
10. What represents the number of protons?

Answers

Answer:

its 10

Explanation:

i took the test

What is an Atomic Model

Answers

Answer:

the structure of an atom, theoretically consisting of a positively charged nucleus surrounded and neutralized by negatively charged electrons revolving in orbits at varying distances from the nucleus, the constitution of the nucleus and the arrangement of the electrons differing with various chemical elements.

Explanation:

How many molecules of SO₃ can be formed from 0.35 moles of O₂ (assuming excess SO₂) from the following UNBALANCED equation?
SO₂(g) + O₂(g) → SO₃(g)

Answers

Molecules of SO₃  : 4.214 x 10²³

Further explanation

The reaction equation is the chemical formula of reagents and product substances  

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products  

Reaction(balanced)

2SO₂(g) + O₂(g) → 2SO₃(g)

mol SO₃ :

[tex]\tt mol~SO_3=\dfrac{2}{1}\times mol~O_2[/tex]

[tex]\tt 2\times 0.35=0.7[/tex]

number of molecules :

1 mol = 6.02 x 10²³ particles(atoms, molecules,ions)

[tex]\tt 0.7\times 6.02\times 10^{23}=4.214\times 10^{23}[/tex]

The number of molecules of SO₃ that could be formed is 4.2 × 10²³ molecules

From the question,

We are to determine the number of molecules of SO₃ that could be formed.

The given chemical equation for the reaction is

SO₂(g) + O₂(g) → SO₃(g)

First, we will balance the chemical equation

The balanced chemical equation for the reaction is

2SO₂(g) + O₂(g) → 2SO₃(g)

This means

2 moles of SO₂ reacts with 1 mole of O₂ to produce 2 moles of SO₃

From the given information

Number of moles of O₂ present = 0.35 moles

Since,

2 moles of SO₂ reacts with 1 mole of O₂ to produce 2 moles of SO₃

Then,

2×0.35 mole of SO₂ will react with the 0.35 mole of O₂ to produce 2×0.35 mole of SO₃

That is,

0.70 mole of SO₂ will react with the 0.35 mole of O₂ to produce 0.70 mole of SO₃

0.70 mole of SO₃ could be produced

Now, for the number of molecules of SO₃ that could be produced,

Using the formula

Number of molecules = Number of moles × Avogadro's constant

∴ Number of molecules of SO₃ that could be formed = 0.70 × 6.022 × 10²³

Number of molecules of SO₃ that could be formed = 4.2154 × 10²³  

Number of molecules of SO₃ that could be formed ≅ 4.2 × 10²³ molecules

Hence, the number of molecules of SO₃ that could be formed is 4.2 × 10²³ molecules

Learn more here: https://brainly.com/question/12823498

2. Determine the heat of reaction (AH,xn) for the process by which hydrazine (N2H4)
is formed from its elements:
N2 (g) +
2 H2 (g) →
N2H4 (g)
by using the following thermochemical data:
N H. (g)
+
O2 (g) →
N2 (g)
-
2 H2O(g)
AH - - 622.2 kJ
H2(g) +
1/2 O2 (g)
H2O (g)
AH = - 285.8 kJ
IN

Answers

The heat of reaction : 50.6 kJ

Further explanation

Based on the principle of Hess's Law, the change in enthalpy of a reaction will be the same even though it is through several stages or ways

Reaction

N₂(g) + 2H₂(g) ⇒N₂H₄(l)

thermochemical data:

1. N₂H₄(l)+O₂(g)⇒N₂(g)+2H₂O(l)   ΔH=-622.2 kJ

2. H₂(g)+1/2O₂(g)⇒H₂O(l)  ΔH=-285.8 kJ

We arrange the position of the elements / compounds so that they correspond to the main reaction, and the enthalpy sign will also change

1. N₂(g)+H₂O(l) ⇒  N₂H₄(l)+O₂(g) ΔH=+622.2 kJ

2. H₂(g)+1/2O₂(g)⇒H₂O(l)  ΔH=-285.8 kJ x 2

2H₂(g)+O₂(g)⇒2H₂O(l)  ΔH=-571.6 kJ

Add reaction 1 and reaction 2, and remove the same compound from different sides

1. N₂(g)+2H₂O(l) ⇒  N₂H₄(l)+O₂(g) ΔH=+622.2 kJ

2.2H₂(g)+O₂(g)⇒2H₂O(l)            ΔH=-571.6 kJ

-------------------------------------------------------------------- +

N₂(g) + 2H₂(g) ⇒N₂H₄(l)   ΔH=50.6 kJ

A 500 mL sample of gas at 960 kpa is compressed to 100 mL. What is the new pressure of the gas?
Please I really need help.

Answers

Answer:

The answer is 4800 kPa

Explanation:

The new pressure can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

Since we are finding the new pressure

[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]

From the question we have

[tex]P_2 = \frac{500 \times 960000}{100} = \frac{480000000}{100} \\ = 4800000[/tex]

We have the final answer as

4800 kPa

Hope this helps you

Which of the following correctly identifies and explains the charge on an atom of
sodium?

Answers

Answer:

The best and most correct answer among the choices provided by your question is the fourth choice.

The data explains that sodium atoms hardly ever form 2+ ions.

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

Explanation:

an 11.5g sample of ethonal 6.00g of Carbon 1.51g of hydrogen what is the percent composition of each element

Answers

C : 52.2%, H : 13.1%, O:34.7%

Further explanation  

The empirical formula is the smallest comparison of atoms of compound forming elements.  

A molecular formula is a formula that shows the number of atomic elements that make up a compound.  

(empirical formula) n = molecular formula  

11.5 g of Ethanol-C₂H₅OH contains 6.00 g of Carbon and 1.51 g of Hydrogen.

mass of Oxygen :

[tex]\tt 11.5-(6+1.51)=4~g[/tex]

Percent composition :

C

[tex]\tt \dfrac{6}{11.5}\times 100\%=52.2\%[/tex]

H

[tex]\tt \dfrac{1.51}{11.5}\times 100\%=13.1\%[/tex]

O

[tex]\tt \dfrac{4}{11.5}\times 100\5=34.7\%[/tex]

(Question) : What is the specific gravity of liquid sample with a mass
of 35.0 g and a volume of. 14.00 mL ?

Answers

Answer:

48.0g is the specific gravity of liquid sample with a mass of 35.0g and a volume of 14.00 mL

Spell out the full name of this compound:
There is a diagram of a seven-membered carbon chain, with a –CH3 group attached to the second and fourth carbons.

Answers

Answer:

nomenclature of alkanes

Explination:

Substituent Formula Number of C Atoms Name of Substituent

CH3                                   1                                         methyl–

CH3CH2                                  2                              ethyl–

CH3CH2CH2                           3                    propyl–

CH3CH2CH2CH2                       4               butyl–

CH3CH2CH2CH2CH2                     5                  pentyl–

and so forth                      and so forth     and so forth

Try this it helped me allot,

Alkenes and alkynes are named in a similar fashion. The biggest difference is that when identifying the longest carbon chain, it must contain the C–C double or triple bond. Furthermore, when numbering the main chain, the double or triple bond gets the lowest possible number. This means that there may be longer or higher-numbered substituents than would be allowed if the molecule were an alkane. For example, this molecule is 2,4-dimethylhept-3-ene (note the number and the hyphens that indicate the position of the double bond).

2,4-dimethylhept-3-ene

or two one carbonsubstituents on the second and third C atoms

its not 3-methylheptane.

PLS HELP!!!
What does it mean when there is a physical change?


A new substance has been formed.


Matter has changed on the molecular level.


Matter has changed from one substance into another.


Matter has changed size, shape or form.

Answers

Answer:

Physical Change. Physical changes are changes in which no bonds are broken or formed. This means that the same types of compounds or elements that were there at the beginning of the change are there at the end of the change.

Fossil fuels are clean-burning fuels. true or false

Answers

Answer:

Energy cannot be converted from one form to another.

Answer:

false

Explanation:

Fossils fuels are actually polluting the atmosphere therefore, it can not be a clean-burning fuel.

if the reactant solution is used to write on a piece of paper and the paper is allowed to partially dry, what can be done to bring out the colored writing

Answers

Answer:

Expose the paper to the atmosphere or moisture

Explanation:

An interesting experiment that demonstrates the equilibrium of complexes is that of the invisible ink.

The invisible ink is pink colored [Co(H2O)6]Cl2 which is essentially colorless and pale when it is used to write on paper. This complex is almost colorless when dilute. Therefore, when it is used in writing, the writing can not be seen.

However, if the paper is left to stand or allowed to absorb moisture; the following equilibrium is set up:

[Co(H2O)6]Cl2 ⇄ [CoCl2(H2O)2] + 4H2O

The formation of blue [CoCl2(H2O)2] on standing or exposure to moisture enables the colored writing to be easily read.

I need it now pleasee help

Answers

Answer:

Their energes can have any values

Explanation:

What is the formula for Mercury ii monohydrogen phosphate?​

Answers

Answer:

CaHPO4 i think

Explanation:

The smallest possible particle of an element is a(n) .

Answers

Answer: Atoms are the smallest particles of an element.

Nose color is an inherited trait in dogs. Two puppies from the same set of parents have different color noses. One puppy has a pink nose and one puppy has a black nose. How can puppies from the same set of parents have different color noses?

A.
The pink-nosed puppy and the black nosed puppy must not actually be related.

B.
The pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents.

C.
The pink-nosed puppy has a different number of chromosomes than the black nosed puppy.

D.
The pink nosed puppy and the black nosed puppy have different chromosomes for the two nose colors.

Answers

Answer:

I thin its B im not sure though

Explanation:

The puppies from the same set of parents have different color noses because the pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents. Thus, the correct option is B.

What is a gene?

A gene is the unit of inheritance which is made up of DNA (deoxyribonucleic acid). Every person receives two copies or alleles of each gene which is inherited from each of the two parent.

Genes are made up of DNA, so each of the chromosome contains many different genes. Genes carry the information which determines the traits or characteristics that are passed on to their offspring or inherited from the parents.

The puppies from the same set of parents have different colored noses because pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents.

Therefore, the correct option is B.

Learn more about Inheritance here:

https://brainly.com/question/14930526

#SPJ2

Define oxidation and reduction.Balance the following redox reaction by ` oxidation number method or ion electrons method.` I_(2)+OH^(-)rarr I^(-)+10_(3)^(-)+H_(2)O

Answers

Answer:

HNO₃ + H₃AsO₃(aq) → NO(g) + H₃AsO₄(aq) + H₂O(l)

Identify the oxidation number of every atom.

Left hand side: H= +1; N= +5; O = -2; As = +3

Right hand side: N = +2; O = -2; H = +1; As = +5

Determine the change in oxidation number for each atom that changes.

N: +5 → +2; Change = -3

As: +3 → +5; Change = +2

Make the total increase in oxidation number equal to the total decrease in oxidation number.

We need 2 atoms of N for every 3 atoms of As. This gives us total changes of -6 and +6.

Place these numbers as coefficients in front of the formulas containing those atoms.

2HNO₃ + 3H₃AsO₃(aq) → 2NO(g) + 3H₃AsO₄(aq) + H₂O(l)

Balance all remaining atoms other than H and O.

Done.

Balance O.

Done.

Balance H.

Done.

Explanation:

Weathering refers to the effects of exposure to A) insults B)pressure C)weather​

Answers

Answer:

c. Weather

Explanation:

Weathering process in genealogically long periods when the surface area has exposed, depends mainly on the climate of the region.

In order for radiation to transfer heat, A electromagnetic waves must be transmitted
B objects must be in direct physical contact C particles must circulate and move in a liquid or gas D thermal energy must move from cold to hot objects.

Answers

Answer : A

Explanation

B- conduction

c - convection

D heat transfer

Answer:

d

Explanation:

The formation of ammonia is represented by the equation N2(g) + 3H2(g) ⇌ 2NH3(g). Determine the enthalpy of formation of ammonia given the following mean bond enthalpies (kJmol-1): N≡N 942; H-H 436; N-H 386

Answers

Answer:

[tex]\Delta _fH_{NH_3}=-66\frac{kJ}{mol}[/tex]

Explanation:

Hello!

In this case, since the study of the bond energy allows us to compute the enthalpies of some reactions, for this combination reaction by which ammonia is yielded, we understand the enthalpy of reaction equals the enthalpy of formation of ammonia, and, in terms of the bonds energy we can write:

[tex]\Delta _fH_{NH_3}=Delta _rH=\Sigma \Delta H(bonds \ broken)-\Sigma \Delta H(bonds \ formed)[/tex]

Whereas the bonds enthalpy of those bonds that get broken cover the N≡N and the three H-H bonds at the reactants side and the enthalpy of those bonds that are formed cover the six N-H bonds at the products; which means we obtain:

[tex]\Delta _fH_{NH_3}=942\frac{kJ}{mol} +3*436\frac{kJ}{mol}-6*386\frac{kJ}{mol}\\\\\Delta _fH_{NH_3}=-66\frac{kJ}{mol}[/tex]

Which differs from the theoretical value that is -46 kJ/mol.

Best regards!

How did you organize the tiles in part A? Describe the method that you used.
Periodic table of numbers tiles

Answers

I need to know part A before I am able to answer this

Answer:

I ordered the tiles from left to right and top to bottom as the numbers kept increasing. The tiles were also organized based on the color and shape that they were. The tiles with the same color and shape were arranged in the same column.

Explanation:

In the modern periodic table, the elements are listed in order of increasing atomic number and elements having similar chemical properties naturally line up in the same column (group).

If one of the reactants in a reaction is Na20, what is known about the products?
A. The products will have no more than 2 Na atoms and 1 0 atom.
B. There is not enough information to say anything about the products.
C. The products will contain exactly 2 Na atoms and 1 O atom.
D. The products will have at least 2 Na atoms and 1 0 atom.​

Answers

Answer:D

Explanation:

A P E X

Googleumbrella umbrella umbrella ​

Answers

oh wow, that truly astonished me in ways words cannot explain!

Answer:

Oh wow!

Explanation:

Cyclopropane, C3H6, is used as a general anesthetic. If a sample of cyclopropane stored in a 2.36-L container at 10.0 atm and 25.0°C is transferred to a 7.79-L container at 5.56 atm, what is the resulting temperature

Answers

The resulting temperature : 546.91 K = 273.91 °C

Further explanation

Boyle's law and Gay Lussac's law  

[tex]\tt \dfrac{P_1.V_1}{T_1}=\dfrac{P_2.V_2}{T_2}[/tex]

P1 = initial gas pressure (N/m² or Pa)  

V1 = initial gas volume (m³)  

P2 = final gas pressure  

V2 = the final volume of gas  

T1 = initial gas temperature (K)  

T2 = final gas temperature  

P₁=10 atm

V₁=2.36 L

T₁=25+273=298 K

P₂=5.56 atm

V₂=7.79 L

[tex]\tt T_2=\dfrac{P_2.V_2.T_1}{P_1.V_1}\\\\T_2=\dfrac{5.56.\times 7.79\times 298}{10\times 2.36}\\\\T_2=546.91~K=273.91^oC[/tex]

How much force is needed to cause a 15 kilogram bicycle to accelerate at a rate of 10 meters per second per second?

Answers

Answer:

F = 150 N

Explanation:

Given data:

Mass of bicycle = 15 kg

Acceleration = 10 m/s²

Force needed = ?

Solution:

Formula:

F = ma

F = force

m = mass

a = acceleration

now we will put the values in formula.

F = 15 Kg × 10 m/s²

F = 150 Kg.m/s²

      Kg.m/s² = N

F = 150 N

How many moles is 4.98x1028 molecules of NaBr?

Answers

Answer:

The answer is 82,724.25 moles

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\ [/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{4.98 \times {10}^{28} }{6.02 \times {10}^{23} } \\ = 82724.2524...[/tex]

We have the final answer as

82,724.25 moles

Hope this helps you

what are the properties of elements??​

Answers

Answer:

Chemical properties

Atomic number. The atomic number indicates the number of protons within the core of an atom.

Atomic mass. The name indicates the mass of an atom, expressed in atomic mass units (AMU).

Electronegativity according to Pauling.

Density.

Melting point.

Boiling point.

Vanderwaal's radius.

Ionic radius.

And many more.

Explanation:

Answer:

Atomic number. The atomic number indicates the number of protons within the core of an atom. ...

. Atomic mass. The name indicates the mass of an atom, expressed in atomic mass units (amu). ...

. Electronegativity according to Pauling. ...

. Density. ...

. Melting point. ...

. Boiling point. ...

. Vanderwaals radius. ...

. Ionic radius.

How many grams are in 3.20 mol of sodium chloride (NaCl)?

Answers

Answer:

5.52 nac

Explanation:

Ground glass is a/an _______ material.
a) soft
b) opaque
c) translucent
d) transparent​

Answers

Answer:

Opaque Material

Answer:

A ground glass is translucent as it allows only partial light to pass through it and forms light shadows

Determine the volume (mL) of 15.0 M sulfuric acid needed to react with 45.0 g of
aluminum to produce aluminum sulfate.

Answers

Answer:

167 mL.

Explanation:

We'll begin by calculating the number of moles in 45 g of aluminum (Al). This can be obtained as follow:

Mass of Al = 45 g

Molar mass of Al = 27 g/mol

Mole of Al =?

Mole = mass /Molar mass

Mole of Al = 45/27

Mole of Al = 1.67 moles

Next, the balanced equation for the reaction. This is given below:

2Al + 3H2SO4 → Al2(SO4)3 + 3H2

From the balanced equation above,

2 moles of Al reacted with 3 moles of H2SO4.

Next, we shall determine the number of mole of H2SO4 needed to react with 45 g (i.e 1.67 moles) of Al. This can be obtained as:

From the balanced equation above,

2 moles of Al reacted with 3 moles of H2SO4.

Therefore, 1.67 moles of Al will react with = (1.67 × 3)/2 = 2.505 moles of H2SO4.

Thus 2.505 moles of H2SO4 is needed for the reaction.

Next, we shall determine the volume of H2SO4 needed for the reaction. This can be obtained as follow:

Molarity of H2SO4 = 15.0 M

Mole of H2SO4 = 2.505 moles

Volume =?

Molarity = mole /Volume

15 = 2.505 / volume

Cross multiply

15 × volume = 2.505

Divide both side by 15

Volume = 2.505/15

Volume = 0.167 L

Finally, we shall convert 0.167 L to mL. This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.167 L = 0.167 L × 1000 mL / 1 L

0.167 L = 167 mL

Thus, 0.167 L is equivalent to 167 mL.

Therefore, 167 mL H2SO4 is needed for the reaction.

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