Dentists use a soft, clay-like material to make a filling for a cavity. The filling stays soft under the light of the dentist’s lamp, but it hardens when the dentist shines an ultraviolet flashlight on it. Why does light from the ultraviolet flashlight harden the filling when light from the lamp does not?

Answers

Answer 1

Answer:

the clay will be melted by the light

Explanation:

because UV rays are hot but in a way, human skin can not feal pain


Related Questions

non-protein amino acid (A) orithine (B) homocysteine

Answers

Answer:

Homocysteine is though to be a non-protein animo acid. however in vintro studies suggest that Homocysteine is likely to be incorporated by inderict

Which method is used to obtain common salt from rock salt? Why?​

Answers

Rock salt or halite is a mineral the contains sodium chloride (table salt) as well as other minerals and impurities. You can remove most of these contaminants using two simple purification techniques: filtration and evaporation.


Materials
Rock salt
Water
Spatula
Filter paper
Funnel
Evaporating dish
Beaker or graduated cylinder
Tripod
Bunsen burner
Filtration
If the rock salt is one large chunk, grind it into a powder using a mortar and pestle or a coffee grinder.
Add 30-50 milliliters of water to six heaping spatula scoops of rock salt.
Stir to dissolve the salt.
Place the filter paper in the mouth of the funnel.
Place the evaporating dish under the funnel to collect the liquid.
Slowly pour the rock salt solution into the funnel. Make sure you don't over-fill the funnel. You don't want the liquid to flow around the top of the filter paper because then it isn't getting filtered.

Answer the following question attached!!

Answers

Answer:

I think It is Covalent. Not 100% sure but like 90% sure.

how many grams are in 1.35 moles of NH3

Answers

n=m(g)/Mwt (3(1)+1(14))
1.35=m/17
m=17*1.35=22.95 g

please help me!! DUE TOMORROW :(

Answers

Answer:

It’s in the photo, sorry if it’s really messy!

Explanation:

Please ask if you have any questions!

11) What volume will 0.75 mol of Oxygen gas (O2) occupy at 298 K and a pressure of 52.7 kPa?

Answers

Answer:

Volume = 35.3L

Explanation:

Use Ideal Gas Law (PV=nRT) and isolate for V (volume) by dividing both sides by P (pressure). You will then get the eqaution listed below and you can solve by using the method I used below.

V = nRT/P

V = (0.75kPa)(8.314)(298K)/(52.7kPa)

V = 1858.179/52.7

V = 35.3L

How many grams of CaSO4 form when
50.0 mL of 0.20 M Ca(NO3)2 react with
excess potassium sulfate solution?
Ca(NO3)2 + K2SO4 → CaSO4 + 2KNO3
-
?] g CaSO4

Answers

Answer:

1.36g CaSO4 (FIXED THIS)

Explanation:

.01 mol CaSO4 is the conversion factor between these values and now you just need to multiply it by the molar mass of .01 x 136.14=1.36g CaSO4

Apologies for having the wrong answer before this, it's been a long day.

What is the formula unit for an ionic compound?

Answers

Answer:

empirical formula

Which of the following materials can conduct electricity?

Plastic pencil case
Rubber band
Steel necklace
Wood ruler

Answers

Answer:

plastics, Styrofoam, paper, rubber, glass and dry air.

Explanation:

Answer:

c

Explanation:

steel is a good conductor therefore,a steel necklace is your answer

mark my brainliest if i make sense enjoy the rest of your day!

How can a redox reaction be identified?
O A. Atoms have rearranged.
O B. Protons have been transferred.
.
O
C. lons are present in solution.
D. Oxidation states have changed.

Answers

Answer:

'Oxidation states have changed.'

Explanation:

Redox Reactions can be identifiable by a change in oxidation number/states of two of the atoms in the reaction. Any reaction in which no oxidation numbers/state change is not a redox reaction.

I want a pharmacist technician to help me with a question please

Answers

I'm a pharmacy dispenser which is the same thing. what's your question?

need help with question please ..
-20 points

Answers

Answer:

B oklolol

[tex][tex]\purple{\rule{45pt}{7pt}}\purple{\rule{45pt}{999999pt}}[tex][/tex]

how many compounds can I make with sodium, hydrogen, oxygen?

will give brainliest and 100 points to the correct answer

Answers

Answer:

маны

Explanation:

Answer:

2H2 + O2 → 2H2O

Explanation:

describe the components of a molecule whose atoms are joined by covalent bonds.

Answers

Answer:

nonmetal

Explanation:

In a covalent bond, the atoms bond by sharing electrons. Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom.

Which of the following expresses the value 300,000,000 in correct scientific notation?
Group of answer choices

3 x 108

0.3 x 10-9

3 x 10-8

0.3 x 109

Answers

Answer:

3 x 10^8

Explanation:

Which of the following is not part of an amino acid?
A. ammonium group
B. carboxylate group
C. ether group
D. unique "R" group

Answers

Answer:

C

Explanation:

Ether group does not exist in amino acids

Ammonium group is on one side

the carboxylate group is opposite to the ammonium group

the R group defines what amino acid it is.

What is the mass of an aluminum block if the density of aluminum is 2.70
g/cm and the volume of that block is 4.8 cm?

Answers

Answer: 50 M

Explanation:

Mass

Density×Volume2.7(4.8)11.6111.6g

Formula used

Density=Mass/Volume

How many grams of O2 are reacted when 3.5
mols of P203 are formed?

Answers

1.45 moles of P2O3 contains 1.45 moles of O3 which means 4.35 moles of O:

1.45 × 3 = 4.35 moles of O

Then you can calculate moles of O2 by dividing it by 2:

4.35 moles ÷ 2 = 2.175 moles of O2 needed

Polyvalent ions are

1) Anions with variable charges
2) Cations from columns 3 to 12
3) Ions that can be positive or negative

Answers

Answer:
3) Ions that can be positive or negative

Hope this helps!

what is the name of CrO2?

Answers

The name is chromium oxide!

Consider the reaction where barium sulfate can be prepared from 2.76 mol of sodium sulfate and excess barium acetate. Sodium acetate is the other product
1.write the balanced MOLECULAR reaction.
2.write the balanced total ionic equation.
3.write the balanced net ionic equation.

Answers

Answer:

1. Na2SO4(aq)+C4H6BaO4(aq) --> BaSO4(s) + 2C2H3NaO2(aq)

2. 2Na^+1(aq) + SO4^-2(aq) + 4C^+4(aq) + 6H^+1(aq) + Ba^-2(aq) + 4O^-2(aq) --> BaSO4(s) + 2C^-4(aq) + 2H^+1(aq) + 3Na^+1(aq) + 2O^-2(aq)

3. Ba^+2(aq) + SO4^-2(aq) --> BaSO4(s)

Explanation:


why compounds with weak molecular forces are usually gases.

Answers

Molecular substances tend to be gases because the intermolecular forces of attraction are comparatively weak. You don't have to break any covalent bonds in order to melt or boil a molecular substance.

The longest intermolecular separation and hence the strongest intermolecular pressure of attraction can be found in the gaseous state of matter.

Although solids' intermolecular interactions were sufficient to maintain themselves in locked places, gases often have weak intermolecular forces that cause them to remain considerably separated. The gases possess greater intermolecular space than solids as a result of these weak forces.

To know more about molecular forces:

https://brainly.com/question/21826959

#SPJ1

Can someone please help. I have no idea how to do this

Answers

Explanation:

c-o number if electrons shared: 4. doubke bond. non polar

c-cl 2 electrons sharde single bond non polar

I know this cause one dash equals 2 electrons chemistry teachers use them when two compounds are sharing electrons rather then using two dots so people know the difference

Giúp mình 2 câu này với ạ
1, Pha 500ml dung dịch HCl 10% (w/v) từ dung dịch 37% (w/w) d=1.19 g/ml
2, Cách pha như thế nào để nhận được 200g dung dịch HCl 25% (w/w) từ dung dịch HCL 37% (d=1.19 g/ml)

Answers

Answer:it is wrong answer

Explanation:estro man

How do the terms genotype and phenotype relate?
O Both are sets of alleles that define traits.
O An organism's phenotype leads to its genotype.
O An organism's genotype leads to its phenotype.
Both are terms for observable traits

Answers

Answer:

c is the

Explanation:

what is the name of the compound N2O5​

Answers

Answer:

Dinitrogen pentoxide also known as Nitrogen pentoxide or nitric anhydride (these are all the same thing just different names people call them)

It’s Dinitrogen pentoxide

What volume of 0.100 M AgNO3 is
needed to react completely with
45.0 mL of 0.230 M Na2S?
2AgNO3 + Na2S → Ag2S + 2NaNO3
[?] mL AgNO3

Answers

Answer:

448mL AgNO3

Explanation:

M x V

n = 0.230 x .045 = 0.01

2AgNO3 + Na2S --> Ag2S+2NaNO3

1 mol Ag2S --> 2 moles AgNO3

.01 mol Ag2S --> ? moles AgNO3

.01x2/1=.02 moles AgNO3

Moles to L conversion is multiplying by 22.4L so we do .02 x 22.4=0.448L

Then we convert to mL so we multiply by 1000 (1000 x 0.448)

448mL AgNO3

There you go friend, good luck with chemistry :)

(Please someone help me!) (No links!)
Please ignore the blue dot, I accidentally pressed it and won't get rid of it!

Answers

Answer:

you picked the right one the net worth of force would be 10

Explanation:

how cuz you got 1 team with 6 force then aother 1 with 4 add em up u get 10

Calculate the vapor pressure in torr of a solution containng 24.5 g of glycerin (C3H8O3) in 135 mL water at 30.0* C; the vapor pressure of water at this temperature is 31.8 torr. Assume that glycerin dissolves molecularly (does not dissociate).

Answers

Psolution = X · PH_20
= 0.966 · 31.8 torr
= 30.7 torr

Which branch of Earth science focuses more specifically on Earth's atmosphere?

Answers

Answer:

Meteorology

Explanation:

Meteorology focuses on Earth's atmosphere and, especially, how changes in the atmosphere affect weather and climate on Earth's surface.

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