Which of the following is a chemical change?
A. Boiling water using fire
B. Breathing in oxygen and breathing out carbon dioxide
C. Ripping a piece of paper in half
D. Melting gold to make jewelry

Answers

Answer 1
B is a physical change, A involves no chemical change, C is a physical change. So your answer is D.

Related Questions

A duck migrates South for the winter about 3000 miles each year. It takes them about 65 hours to travel this distance. What is the velocity of the duck?

Answers

Answer:

46.15

Explanation:

Their was a watch and learn assignment and I wasn’t paying attention and we had questions so if you guys have ever done this before please help me out. You can’t answer if you haven’t your teacher conduct this experiment or if you have answers from a friend or something

Answers

The man rushes through your door with his fists in the air, all of the sudden your vision went black, and he had stolen your points.

Calcium metal reacts with hydrochloric acid (HCl) to form aq calcium chloride and hydrogen gas.
Ca(s)+2HCl(aq) -----------> CaCl2(aq)+H2(g)
0.401 g of calcium metal is reacted with 0.350L of 0.0400M hydrochloric acid.
(a) Write the complete ionic equation of the reaction.
(b) Calculate the moles of calcium and hydrochloric acid.
(c) Identify the limiting reagent.
(d) Assuming complete reation, determine the moels of excess reagent that reamains in the reaction.

Answers

Answer:

a. Ca(s) + 2H⁺ → Ca²⁺ + H₂(g)

b. 0.0100 moles Ca; 0.0140 moles HCl.

c. HCl is limiting reactant.

d. 0.0030 moles of Ca

Explanation:

a. In water, HCl dissociates in H⁺ and Cl⁻ and CaCl₂ in Ca²⁺ and 2 Cl⁻. The ionic equation is:

Ca(s) + 2H⁺ + 2Cl⁻ → Ca²⁺ + 2Cl⁻ + H₂(g)

Ca(s) + 2H⁺ → Ca²⁺ + H₂(g)

b. Moles Ca -Molar mass 40.1g/mol-:

0.401g * (1mol / 40.1g) = 0.0100 moles Ca

Moles HCl:

0.350L * (0.0400mol / L) = 0.0140 moles HCl

c. In the reaction, 1 mole of Calcium reacts with 2 moles of HCl.

For a complete reaction of 0.0100 moles of Calcium there are necessaries:

0.0100mol Ca * (2 mol HCl / 1 mol Ca) = 0.0200 moles HCl

As there are just 0.0140 moles of HCl,

HCl is limiting reactant

d. For a complete reaction of 0.0140 moles of HCl, the moles of Ca that react are:

0.0140 moles HCl * (1 mol Ca / 2 mol HCl) = 0.0070 moles Ca

That means will remain:

0.0100 moles - 0.0070 moles:

0.0030 moles of Ca

What’s the full electronic configuration for lead

Answers

Answer:

1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2, 4f14, 5d10, 6p2.

Explanation:

mark as brainliest

HELP!!!
IF YOU DONT KNOW THE ANSWER THEN PLEASE DONT ANSWER!!

Answers

Answer:

1. melting

2. freezing

5. condensation

6. evaporation

A sample of gas contains 0.1200 mol of NH3(g) and 0.1500 mol of O2(g) and occupies a volume of 13.0 L. The following reaction takes place: 4NH3(g) + 5O2(g)4NO(g) + 6H2O(g) Calculate the volume of the sample after the reaction takes place, assuming that the temperature and the pressure remain constant.

Answers

Answer:

14.44 Liters

Explanation:

4NH3(g) + 5O2(g) -----> 4NO(g) + 6H2O(g)

From the equation of the reaction, the mole ratio of NH3 to NO2 = 1:1

Therefore 0.12 moles of NH# produces 0.12 moles of NO

Also from the equation of reaction, mole ratio of NH3 to H20 is 4:6

Therefore, 0.12 moles of NH3 will produce  0.12 * 6/ 4 moles of H2O =0 0.18 moles of H2O

Total moles of gases produced = 0.30 mole

From Avogadro's law:

v1/n1 = v2/n2

v1 = 13.0 L

n1 = 0.12 + 0.15= 0.27 moles

v2 = ? =

n2 = 0.30

V2 = v1n2/n1

v2 = 13.0 * 0.30/0.27

V2 = 14.44 Liters

Determine the mass of CaCl2·2H2O(MW 147.02g/mole) to weigh out using a four-place analytical balance to prepare 100mL of a 0.1005M solution of Ca2+.

Answers

Answer:

1.4776 g

Explanation:

First, let us determine the number of moles present in  100 mL of 0.1005 M solution of Ca2+.

mole = molarity x volume in Liter

mole of Ca2+ = 0.1005 x 0.1 = 0.01005

Also,

mole = mass/molar mass

mass of 0.01005 mole Ca2+ = mole x molar mass

                 = 0.01005 x 147.02 = 1.4776 g

Since 1 mole of Ca2+ is present is 1 mole of CaCl2·2H2O, 1.4776 g of CaCl2·2H2O would be weighed out in order to prepare 00mL of a 0.1005M solution of Ca2+.

To prepare a 100 mL solution of 0.1005 M [tex]Ca^2^+[/tex], we would need to weigh out approximately 14.737 grams of [tex]CaCl_2.2H_2O[/tex].

We must use the molar mass and molarity formula to calculate the mass of [tex]CaCl_2.2H_2O[/tex] needed to make a 0.1005 M solution of [tex]Ca^2^+[/tex].

Let's start by figuring out how many moles of [tex]Ca^2^+[/tex]are needed for the solution:

Molarity (M) = moles/volume (L)

0.1005 M = x moles/0.1 L (100 mL converted to liters)

x = 0.1005 moles of [tex]Ca^2^+[/tex]

So, the molar mass of [tex]CaCl_2.2H_2O[/tex]:

Ca (40.08 g/mol) + 2Cl (35.45 g/mol) + 2([tex]H_2O[/tex]) (2 * 18.02 g/mol) = 147.02 g/mol

Then, we calculate the mass

Mass = moles * molar mass

Mass = 0.1005 moles * 147.02 g/mol

Mass = 14.737 grams

Therefore, to prepare a 100 mL solution of 0.1005 M [tex]Ca^2^+[/tex], we would need to weigh out approximately 14.737 grams of [tex]CaCl_2.2H_2O[/tex].

Learn more about Molar mass, here

https://brainly.com/question/31545539

#SPJ6

A 30.0 mL sample of 0.200 M Ba(OH)2 is titrated with 0.100 M HCl.
a) Determine the pH of the solution before the addition of HCl.
b) Determine the pH of the solution after the addition of 25.0 mL HCl.

Answers

Answer:

what's the question? is it A

A 30.0 ml sample of 0.200 M Ba(OH)2 is titrated with 0.100 M HCl. teh pH will be:

a) The pH of the solution before the addition of HCl is 13.301.

b) The pH of the solution after the addition of 25.0 mL HCl is 13.494.

What is pH?

pH is potential hydrogen. It is the measurement of the acidity and basicity of any solution.

a)

[tex]\rm Ba(OH)_2 = Ba_2+ + 2OH^-Ba(OH)_2[/tex]

Given, [OH¯] = 0.200 M

pOH = -log 0.200 = 0.699

pH = 14.000 - pOH = 14.000 - 0.699 = 13.301

b)

Now 25 ml HCl is added

0.025 × 0.100 = 0.0025

Moles of OH = 0.02 × 0.0025 = 0.0005

Remaining OH =   0.0025 – 0.0005  = 0.00245

Now calculate the pH

0.055 is divided by 0.200 = 0.275

pOH = -log 0.275 = 0.5606

pH = 14.000 - 0.5606 = 13.4394

Thus, a) 13.301.

b) 13.4394.

Learn more about pH

https://brainly.com/question/15289741

A child and his mother both have blue eyes. They both have blue eyes because inherited traits of an organism are governed by the -


A. chromosomes found in the genes

B. nucleus found in the chromosomes

C. genetic material found in the nucleus

D. genes found in the cytoplasm

Answers

the answer would probably be c.

Answer: the answer is C hope it helps

Explanation:

The molar mass of an imaginary molecule is is 93.89 g/mol. Determine its density at STP.

Answers

Answer:

Density = 4.191 gm/L

Explanation:

Given:

Molar mass = 93.89 g/mol

Volume(Missing) = 22.4 L (Approx)

Find:

Density at STP

Computation:

Density = Mass/Volume  

Density = 93.89 / 22.4  

Density = 4.191 gm/L

What is the mass number of an atom that has six protons , six electrons and eight neutrons

Answers

Answer:

14

Explanation:

Given parameters:

Number of protons  = 6

Number of electrons  = 6

Number of neutrons = 8

Unknown:

Mass number  = ?

Solution:

The mass number of an atom is the sum of protons and neutrons in an atom;

 Mass number  = number of protons + number of neutrons

 Mass number  = 6 + 8  = 14

9.78 cm equals how many
mm

Answers

The Formula for cm to mm is cm x 10 = mm so to replace it it would be, cm=9.78, so
9.78 x 10 = 97.8 mm hope this helped :) plz mark brainliest ʕ•ᴥ•ʔ

Answer:

97.8

Explanation:

What force works against friction

Answers

Answer:

work done

Explanation:

i think

work done

this is answer

Which is the best example for genetic diversity?

Answers

Answer:

Genetic Diversity Examples

Different breeds of dogs. ...Different varieties of rose flower, wheat, etc.There are more than 50,000 varieties of rice and more than a thousand varieties of mangoes found in India.

Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species.

Explanation:

i hope this helps u.

HELPPP!!!
Empty chemical containers may be re-used for storing food or water after thorough washing.
False
True

Answers

Answer:

False

Explanation:

That would still be very unsafe

Answer:

False

Explanation:

even thought it may be washed completely certain chemicals can still remain and be harmful when you consume the food that is put into. Especially if you add heat or cold to the container.

PLEASE PLEASE ANSERR THIS PLEASEEEE

Answers

Answer:

I think it is c

Explanation:

Which of the following is true about wind and water changing the size of mountains over many millions of years? A: The continuous movement of wind and water changes the size of mountains over many millions of years B: Nothing can change the size of mountains over many millions of years not even the continuous movement of wind and water. C: The continuous movement of wind and water changes the size of some mountains, but not all mountains D: Even though mountains change in size over many millions of years, the changes are not due to the continuous movement of wind and water​

Answers

Answer:

I would say A

Explanation:

normally wind and water will work together to erode or brake away a cliff or mountain.

There is an example of this in Illinois (There are eroded away cliffs located next to the Mississippi River, they stretch from around Grafton to Alton).

What statement best describes what a circle graph shows?
A. The average of a data set
B. A frequency distribution
ООО
C. The relationship between two variables
D. Data as proportions of a whole

Answers

I think it’s B I’m not sure
Pretty sure it’s D

-the arcs of acs of a circle graph are proportional to how many percent of population gave a certain answer. they are used to separate peoples opinions so it’s like a data thing-

3
Select the correct answer.
Which form of light can a human eye see?
O A infrared light
OB.
near-infrared light
-
O c. ultraviolet light
OD
visible light

Answers

Answer:

human can see visible light

Answer:

i beleive it is D. visible light

Explanation:

if im wrong sorry this subject isnt my forte

What type of cells are gametes?

Answers

Answer:

Reproductive cells(also known as sex cells) are gametes.

Explanation:

Have a great day :)

Answer:

Gametes are an organism's reproductive cells

Explanation:

Calculate the mass of 5.3 moles of chloric acid (hcl03)

Answers

If I did the math right .. it would be 84.46grams

Explain how the petrol and bitumen fractions differ in their properties and uses. (6 marks)

Answers

Explanation:

petrol or bitumen and at least one use of petrol and at least one use of bitumen eg petrol has a lower boiling point and is used as a fuel in cars, bitumen is more viscous and is used to surface roads.Aug 19, 2015

Petrol and bitumen fractions differ in their properties and uses in a number of ways with regard to melting point, viscosity, ignition ,combustion .

What is the difference between petrol and bitumen fractions?

Petrol has less number of carbon chains while bitumen has large number of carbon chains.Bitumen has higher melting and boiling point as compared to petrol.

Petrol has higher viscosity as compared to bitumen.It combusts easily while bitumen does not combust completely ,it produces large number of carbon monoxide or soot.

Petrol fractions are used in cars,motorbikes,etc. while bitumen fractions are used in road surfaces and roofing. Boiling point of petrol is 35-70°C while that of bitumen is 700°C.Bitumen is more viscous as compared to petrol.

Learn more about petrol&bitumen fractions,here:

https://brainly.com/question/14307804

#SPJ2

What evidence was used in the investigation of the Gaetane Bouchard's murder? Was it considered class evidence or individual evidence?

Answers

Answer:

class i believe

Explanation:

β-Myrcene, a key intermediate in the production of several fragrances, is 7-methyl-3-methylene-1,6-octadiene.Draw the structure of this triene.

Answers

Answer:

this is the structure of beta myrcene but im notsure which structure you were looking for

Dry ice is carbon dioxide in the solid state. 1.28 grams of dry ice is placed in a 5.00 L chamber that is maintained at 35.1°C. What is the pressure in the chamber after all of the dry ice has sublimed? Assume ideal gas behavior.

Answers

Answer:

0.15atm

Explanation:

Given parameters:

Mass of dry ice = 1.28g

Volume of chamber  = 5L

Temperature  = 35.1°C = 35.1 + 273  = 308.1K

Unknown:

Pressure in the chamber  = ?

Solution:

As we assume ideality for the gases in the cylinder, we use the equation below to solve the problem;

             PV  = nRT

P is the pressure

V  is the volume

n is the number of moles

R is the gas constant  = 0.082atmdm³mol⁻¹k⁻¹

T is the temperature

 

 Let us find the number of moles;

       Molar mass of CO₂  = 12 + 2(16) = 44g/mol

  Number of moles of  CO₂ = [tex]\frac{mass}{molar mass}[/tex]

  Number of moles of CO₂  = [tex]\frac{1.28}{44}[/tex]   = 0.03moles

 So;

Input the parameters and solve;

        P x 5  = 0.03 x 0.082 x 308.1

         5P  = 0.73

           P = [tex]\frac{0.73}{5}[/tex]   = 0.15atm

A
map shows the physical properties or characteristics of a region.
highway
topographical
population
computer
compound

Answers

Answer:

Topographical is the correct ans

Sal drew the electron dot diagram as shown.
How should Sal correct diagram?

Answers

Answer:

Answer: He should add a single dot below the symbol to correct the electron dot diagram of an aluminium atom.

Explanation: Electron dot structures are the structures in which valence electrons around an atom are shown. The electrons are represented as dots in these structures.

Aluminium is the 13th element of the periodic table.

Electronic configuration of Aluminium is given by:

Valence electrons of aluminium = 3

In the given image, 2 valence electrons are shown and total number of valence electrons are 3. So, in order to correct the diagram, he should add a single electron below the symbol.

Explanation:

yes giuve me brainliest

Which of these is given away or accepted by an atom when it reacts with other atoms?

Electron
Neutron
Nucleus
Proton

Answers

A; Electron is your answer.

Answer:

Electron

Explanation:

An atom can either gain, share, transfer, and/or lose electron(s)

When you consume food, it goes through mechanical and chemical digestion in the mouth and is then transported to the
stomach. It then mixes with stomach acid and other enzymes. What type of digestion is taking place within the stomach?
Physical change
Absorption
Mechanical digestion
Chemical digestion

Answers

Answer:

Chemical digestion

Explanation:

The type of digestion taking place within the stomach is chemical digestion. When food reacts with stomach acids and other enzymes, a reaction takes place which reduces the food into simpler bits.

The stomach contains strong digestive acids. Cells in the stomach secrete hydrochloric acid to further aid the digestion of the food. This way, complex organic molecules becomes broken down into simpler units.

Which of the following is a pure substance?​

Answers

Answer:

Examples of pure substances include tin, sulfur, diamond, water, pure sugar (sucrose), table salt (sodium chloride) and baking soda (sodium bicarbonate). Crystals, in general, are pure substances. Tin, sulfur, and diamond are examples of pure substances that are chemical elements. All elements are pure substances

Explanation:

Other Questions
model the relationship between gravity and altitude On the coordinate plane below, quadrilaterals TRAP and HELP are similar to each other.The existing dimensions of TRAP are increased and as a result, the original area of the quadrilateral is doubled. Consider the changes in the area of TRAP and determine the new ratio of the areas of TRAP to HELP.A. 4:1B. 32:1C. 16:1C. 8:1 Jonathan looked at the picture frame below and computed the following sum: 8 3/4 + (-4) what value did he find?a. xb. 2xc. yd. 2y an someone explain Costas Levels of Questioning?1,2,and 3 i have a lot more coming it's just me giving away all my points every time i reach 1000.i can only give 50 at a time tho, these are all back to back btw. Have a blessed day. 100 POINTS !!URGENT!!After the reading and watching of the wedding, do you believe that Romeo and Juliet truly love each other? Helppppppppppppppppppppp 46.875 in a fraction Jim borrows $790 for 4 months. He pays a simple interest rate of 6%. How much interest must he pay? Round your answer to the nearest cent if necessary. PLEASE HELP!! NEED ANSWERS ASAP Why would a Roth 401(k) investment plan allow you to invest the most amount of money? a. The federal government subsidizes a portion of a Roth 401(k) to help people in lower tax brackets save for retirement. b. Roth 401(k) plans are reserved for administrators and executives, who have a higher income which would allow them to invest more. c. A Roth 401(k) plan takes money after tax has been removed from gross income, and has a contribution limit, but withdrawal is tax free. d. The contribution limit of a Roth 401(k) plan is more than double the limit of the traditional 401(k). Please select the best answer from the choices provided A B C D Duffy completed a 50-meter dash in 36 seconds. That was 90 percent of the time it took Paul to complete it. What was Paul's time?A. 36 secondsB. 42 secondsC. 40 seconds 20 pts, try to find short story and novel pages, A novel has 13 times as many pages as a short story. The combined number of pages in the books is 448 pages. How many pages are in each book?Short Story:Novel: The location of any electron in an atom can be described byunique quantum numbers. i'll give brainliest.please put the answers by the question numbers :D what is an example of an unclear question related to polling how many soldiers does Salem appear prepared to equip? what is the answer??5x - (y + 2z) A machine used to shred cardboard boxes for composting has a first cost of $10,000, an AOC of $7000 per year, a 3-year life, and no appreciable salvage value. Assume you were told that the service provided by the machine will be needed for only 5 years, which entails a repurchase and retention for only 2 years. What salvage value, S, is required after 2 years in order to make the 2-year AW value the same as it is for its 3-year life cycle AW? Assume i = 10% per year. Solve using factors and, if assigned, using a spread- sheet and Goal Seek. 2( z + 1 ) - 4(z - 4) 2(z + 5)please help