You forgot to dry the bread knife when you washed it and reddish brown spots appeared on it. is it chemistry or physical change?

Answers

Answer 1

Answer:

Chemical because water + metal = rust.

Explanation:

A new substance was formed.


Related Questions

What is the shortest day of the year known as? A.vernal B.equinox C.winter D.solstice summer solstice E.autumnal equinox

Answers

Answer:

summer solstice

Explanation:

on june solstice the northen hemisphere leans more toward the sun giving us longer days and more strong sunlight and It's the opposite in the Southern Hemisphere where june marks the start of winter thus its the shortest day of the year

Your grandmother wants to build a small garden in her backyard.She lives near a city and doesn't have a large budget for this.Should she use an organic or inorganic fertilizer?​

Answers

Answer:

So if you are buying, Inorganic is cheaper but at the cost of it's quality, organic fertilizer is better quality that's why it is more expensive, both work so if you want the cheaper option that's fine it still works

Explanation:

if the reactants of a reaction have ab initial mass of 25 grams what is the mass of the product?

Answers

Answer:

It remains the same

Explanation:

The law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. For example, the mass of sodium plus the mass of chlorine that reacts with the sodium equals the mass of the product sodium chloride.

what can you do to see what season another planet experiences?

Answers

Answer:

Observe the other planet throughout the year. Look at the environment when the season changes to see what changes in the environment.

Answer:

Every planet in the solar system has seasons. Extraterrestrial seasons are hardly noticeable on some planets (Venus), mindbogglingly extreme on others (Uranus) and in some cases simply impossible to define (Mercury).


Hydrochloric acid reacts with sodium hydroxide according to the equation:
NaOH + HCl 2 NaCl + H2O
25 cm of NaOH was neutralized by 26 25 cm of 0 1 mol/dm HCI
a
Calculate how many moles of HCI was neutralized
b
Calculate how many moles of NaOH was neutralized.
Calculate the concentration of the NaOH used​

Answers

Answer:

Explanation:

Hydrochloric acid reacts with sodium hydroxide according to the equation:

NaOH + HCl ------> NaCl + H2O

25 cm of NaOH was neutralized by 26. 25 cm^3 of a 0.1 M solution of HCl.

Calculate how many moles of HCI was neutralized

if 1 liter of the HCl has 0.1 moles, 100 ml has 0.01 moles  

so 26.25 ml has 0.01 X26.25/100 moles or 0.002625 moles

b

Calculate how many moles of NaOH was neutralized.  the reaction is 1:1

so 0.002625 moles of NaOH were reacted.

Calculate the concentration of the NaOH used​

25 ml of NaOH were used so the concentration was

(0.002625/25) x 10^3=0.000101X1000 =0.105 MOLES/LITER

Knowing how electrons behave in metallic materials, describe why metals make great conductors of heat

Answers

Answer:

Below

Explanation:

Metallic compounds are excellent conductors of heat due to the fact that their electrons, instead of orbiting their respective atoms, form a sea of electrons around the positively charged nuclei of the interacting metal ions. These electrons are able to move freely around and bond, allowing them to conduct heat well.

Hope this helps! :)

how many calories are required to boil 75 grams of water not in sig figs

Answers

Well, each ml of water requires one calorie to go up 1 degree Celsius, so this liter of water takes 1000 calories to go up 1 degree Celsius. (There are 1000 ml, each of which needs to have its temperature raised.)

13. Acid-catalyzed dehydration-condensation reactions of carboxylic acids and alcohols produce chemicals called
esters.
i. Using carbon skeletal notation, write the dehydration-condensation reaction that occurs between ethanol
and butanoic acid.
ii. What is the name of this ester?

Answers

Answer:

A condensation reaction joins two larger molecules by splitting out a smaller molecule — usually water or ammonia — between them.

In an esterification reaction, an OH  from the acid and an H from the alcohol form a molecule of water.

The larger parts join to form the ester.

Ethanol and butanoic acid react to form ethyl butanoate.

Acid-catalyzed dehydration-condensation reactions of carboxylic acids and alcohols produce chemicals called "esters". The dehydration-condensation reaction occurs between 'ethanol' and 'butanoic acid' giving an ester called as "ethyl butanoate".

What is an ester and how it is formed?Esters are produced when carboxylic acids are heated with alcohols in the presence of an acid catalyst. The catalyst is usually concentrated sulphuric acid. Dry hydrogen chloride gas is used in some cases, but these tend to involve aromatic esters (ones containing a benzene ring).Esters are represented by the formula RCOOR', where R and R' are hydrocarbon groups. The chemical reaction occurring in the formation of the ester is known as an esterification reaction.

The reaction that occurs between ethanol and butanoic acid:

Ethanol reacts with butanoic acid in the presence of an acid-catalyst and gives ethyl butanoate as ester and water as products. If an acid reacts with a base, salt and water are the products. But ester is not a salt.

i) The carbon skeletal notation for the given reaction is shown below.

ii) The ester is named "ethyl butanoate".

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Đối với nguyên tử của các nguyên tố trong cùng một nhóm (trừ 2 cột cuối của nhóm VIIIB), mối quan hệ giữa số thứ tự của nhóm và electron hóa trị như thế nào?

Answers

Answer:

For atoms of elements in the same group (except the last 2 columns of group VIIIB), what is the relationship between the group number and the valence electron?

What are the 4 properties of hydrogen bonds?

Answers

Answer:

Solubility, Volatility, Viscosity and Surface Tension.

I need help with these questions.

Answers

Answer:

descritive advective also know as qualitative

describe the composition and structure of the compound fluoride

Answers

Answer: sodium (Na +) cation and fluoride (F -) anion

Explanation:

Formula and structure: The chemical formula of sodium fluoride is NaF and its molar mass is 41.99 g/mol. It is a simple ionic compound, made of the sodium (Na +) cation and fluoride (F -) anion. The solid salt exists as cubic crystals similar to the crystal structure of sodium chloride (NaCl).

WILL MARK AS BRAINLIEST IF CORRECT

Answers

Answer:

I don't know what is the actual answer

What is the difference between primary scale and extension scale?

Answers

Answer:

8txirzrz8rzrirzriz£=,£=,,-8/-9/-¥/

Explanation:

otcitxfi

The least dense gas is

neon
fluorine
krypton
chlorine

Answers

Answer:

Out of the options provided Neon is the least dense gas

Explanation:

The correct answer is neon

what is the atomic number of this atom?​

Answers

Answer:

4

I think so

have a great day

Answer:

I think it is option one (3)

Qué tipo de energía tiene un sacapuntas

Answers

Answer:

creo q es electrico

Explanation:

12. Using the two equations E = hv and c= lv, derive an
equation expressing E in terms of h, c, and \.

Answers

[tex]\\ \sf\longmapsto c=\lambda v[/tex]

[tex]\\ \sf\longmapsto v=\dfrac{c}{\lambda}[/tex]

Now

[tex]\\ \sf\longmapsto E=hv[/tex]

Put value of v found before

[tex]\\ \sf\longmapsto E=\dfrac{hc}{\lambda}[/tex]

define isotope
hello​

Answers

Answer:

Isotope is one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behaviour but with different atomic masses and physical properties.

Hello Sis!!!!!!

Answer:

Isotopes are atoms of the same element that have the same atomic number but different in mass number.

HELPPP PLEASE ITS ABOUT MOLARITY

Answers

Answer:  0.178 mol

Explanation:

We can use the formula M₁V₁ = M₂V₂ to determine the moles remaining after the volume is decreased due to evaporation..  

Since M₁V₁ = M₂V₂    (starting mole × starting volume = end mole × end volume)

⇒  (0.125 mol)(265 mL) =  M₂ (186 mL)

         33.125 mol/mL =  186 mL × M₂

⇒                      M₂ = 33.125 mol/mL ÷ 186 mL

                              = 0.178 mol

a. What type of elements are found in each group?

Answers

Answer:

Groups are numbered 1–18 from left to right. The elements in group 1 are known as the alkali metals; those in group 2 are the alkaline earth metals; those in 15 are the pnictogens; those in 16 are the chalcogens; those in 17 are the halogens; and those in 18 are the noble gases.

HOPE IT'S HELP

FOLLØW ME PLEASE THANKS IN ADVANCE

Heart my answer if it's helpful

BRAINLIEST MY ANSWER IF you want

WILL GIVE BRAINLIEST TO THE CORRECT ANSWER along with the points


6. A food supply company produces Yellow-42 (from previous example) in 200-gram wholesale bottles. How many grams of FeCl3 would be needed to produce one bottle of Yellow 42?


7. How much NaOH would be needed to produce one bottle of Yellow 42?


8. Iron (III) chloride is fairly expensive, and the company does not want to waste any during the reaction process. How could the company set up this reaction in a way that ensures no iron (III) chloride is wasted in the reaction?

Answers

A food supply company produces Yellow-42 (from previous example) in 200-gram wholesale bottles. The grams of FeCl3 needed to produce one bottle of Yellow 42 is 303.638 grams.  The amount of NaOH needed to produce one bottle of Yellow 42 is 226.32 grams.

The mass amount of Yellow 42 = 200 gramsThe molar mass of Fe(OH)3 needed to produce 1 bottle of Yellow 42 = 106.845 g/mol

Using the relation for the number of moles which is:

[tex]\mathbf{number \ of \ moles = \dfrac{mass }{molar \ mass}}[/tex]

[tex]\mathbf{number \ of \ moles \ of \ Yellow \ 42 = \dfrac{200 g }{106.867 \ g/mol}}[/tex]

[tex]\mathbf{number \ of \ moles \ of \ Yellow \ 42 =1.872 \ moles}[/tex]

Now,

If 1 mole of Fe(OH)₃ requires 1 mole of FeCl₃1.872 moles of Fe(OH)₃ will require 1.872 moles of FeCl₃

Mass of FeCl₃ required = number of moles of  FeCl₃ × molar mass of FeCl₃

Mass of FeCl₃ required = 1.872 moles × 162.2 g/mol

Mass of FeCl₃ required = 303.638 grams

7.

Recall that:

1 bottle of the yellow requires 1.872 moles of the Fe(OH)₃Thus, 1 mole of Fe(OH)requires 3 moles of NaOH

Now, 1.872 moles of Fe(OH)will require (3 × 1.872 moles of NaOH)

= 5.616 moles of NaOH

Thus, the amount of NaOH in grams, that will be needed to produce one bottle of Yellow 42 is:

= 5.616 moles × 40.3 g/mol (molar mass of NaOH)

= 226.32 grams of NaOH

8.

The company could set up this reaction in a way that ensures no iron (III) chloride is wasted in the reaction by using the concept of the stoichiometry of the reaction involved in the system and he should feed the reactant within the ratio of 1:3 for FeCl₃ and NaOH respectively.

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Hello! please help :(

Answers

i can only answer b) ii.

convert 2.5 X 10^24 atoms of copper to grams of copper

Answers

2.5 X 10²⁴ atoms of copper is equivalent to 266.7g of Cu.

HOW TO CALCULATE MASS:

The mass of a substance can be calculated by multiplying the number of moles of the substance by its molar mass. That is;

mass of substance (g) = no. of moles (mol) × molar mass (g/mol)

However, the number of moles of copper must first be calculated by dividing the number of atoms by Avogadro's number as follows:

no. of moles of Cu = 2.5 X 10²⁴ ÷ 6.02 × 10²³

no. of moles = 2.5/6.02 × 10²⁴-²³

no. of moles = 0.42 × 10¹

no. of moles = 4.2moles of copper.

Molar mass of copper = 63.5g/mol

Mass of copper = 4.2mol × 63.5g/mol

Mass of copper = 266.7g

Therefore, 2.5 X 10²⁴ atoms of copper is equivalent to 266.7g of Cu.

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An atom of beryllium can be represented as 9/4Be.
Describe the structure of the beryllium atom.
in your answer make reference to the number of subatomic
particles and where they are found in the atom

Answers

9 nucleons, including, 4 protons found with 5 neutrons in the nucleus at the center, along with 4 elections in too energy levels surrounding it.

The heat of solution of KI is 20.3 kJ/mol.
This means that when one mole of KI dissolves in water the process will be
PLEASE EXPLAIN ANSWER

a. Exothermic, ΔH is positive
b. Exothermic, ΔH is negative
c. Endothermic, ΔH is negative
d. Endothermic, ΔH is positive

Answers

Since the heat of solution of KI is 20.3 kJ/mol, the answer to the question is a. Exothermic, ΔH is positive

There are two types of chemical reactions namely exothermic and endothermic reaction.

For exothermic reactions, heat is released. So, ΔH is positiveFor endothermic reactions, heat is absorbed. So, ΔH is negative

Given the heat of solution of KI as 20.3 kJ/mol.

Since it is positive, the reaction is exothermic and  ΔH is positive

Since the heat of solution of KI is 20.3 kJ/mol, the answer to the question is a. Exothermic, ΔH is positive

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A model of Nuclear Fusion?

Answers

Answer:

a proton turns into an atom that goes kabloey into fission products and other neutrons.

Explanation:

Help!! Need it asap thankyou!

Answers

Answer:

ano gagawin dyan? HAAHAHA

Which statements about nuclear fission and nuclear fusion are true? Select the two correct answers. (1 point)
They both occur in the nucleus of an atom
They both involve two atoms fusing into one atom
They both reloase large amounts of energy
They both involve one atom splitting into two atorns

Answers

Statements that describes nuclear fission and nuclear fusion as regards this question are:

C: They both release large amounts of energy

D:They both involve one atom splitting into two atoms.

Both fission and fusion can be regarded as nuclear reactions that brings about production of  energy. However they have different applications.

Fission can be explained as the splitting of a heavy as well as unstable nucleus into two nuclei , but this nuclei are lighter compare to the mother nucleus.

Fusion on the other hand can be regarded as a  process involving  two light nuclei coming together to form one and then  release vast amounts of energy

For instance,  uranium will undergo  fission to produce strontium and krypton nuclei

Therefore, option C, D are right.

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Answer:

C: They both release large amounts of energy

D: They both involve one atom splitting into two atoms

How much heat is needed to vaporize 10.0 grams of water?

Answers

10*2260=22600j=22.6kJ
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