What does purified water and fluorine make?
Answer:
Adding fluoride to the water supply reduces the incidence of tooth decay. Fluoride protects teeth from decay by demineralization and remineralization. Too much fluoride can lead to dental fluorosis or skeletal fluorosis, which can damage bones and joints.
Explanation:
N/A
You have a container which has the capacity to hold 3 L water. If it already has 2.25 L water in it, how much more water in mL can you still add to fill it completely?
* Urgent Bet no one knows this *
Answer: The name of the super continent that existed millions of years ago.
Explanation:
Our continents as they exist today were once joined together into a super continent known as Pangea. Over the millennia, the land masses broke off and drifted away creating the location of the continents we know today.
(つ ^‿^ )つ Hey there!
Answer → Is the second answer, The name of the super continent that existed millions of years ago.
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What is climate? What are three things that cause the earths climate?
Answer:
The climate has been caused by many natural factors including changes in the sun emissions from volcanoes variations in Earth's orbit and levels of carbon dioxide. Global climate change has typically occured very slowly over thousands or millions of years .The three causes of the Earth's climate are
Industrial activitiesAgricultural activitiesDeforestationthese are the causes of the Earth's climate.
Climate is a average weather in a given area for a long period of time is called a climate
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A barometer is used to measure air pressure.
Please select the best answer from the choices provided
Т
F
name this structure
Answer:
The fourth one- bromo trifluoro methane
Explanation:
Answer:
D
Explanation:
I believe the answer is the 4th option, bromo-trifluoro-methane
What is the composition of a universal indicator?
Answer:
The main universal indicator is in the form of a solution and are thymol blue , methyl red , bromothymol blue and phenolphthalein this mixture is important because each component loses or gains protons depending upon the acidity of the solution being tested .
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Which of these items is made up of one or more molecules?
Gold
Hydrogen
Salt
Neon
The item that is significantly made up of one or more molecules is hydrogen. Thus, the correct option for this question is B.
What is a Molecule?A molecule may be defined as a group of one or more atoms that are held together by numerous chemical bonds. It is the smallest particle of a substance that has all sorts of physical and chemical properties of that substance.
Among the given options, gold and neon are the elements, while salt is a compound. Hydrogen is a gas of diatomic molecules bearing the formula H2. It is colorless, tasteless, odorless, non-toxic, and highly combustible. Hydrogen in its molecular form is more common.
A hydrogen molecule is one of the simplest possible molecules which significantly consists of two protons and two electrons. These protons and electrons are remarkably held together by electrostatic forces.
Therefore, the item that is significantly made up of one or more molecules is hydrogen. Thus, the correct option for this question is B.
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B) Which of these is NEVER an example of freshwater? A) Pacific Ocean B) Okefenokee Swamp Mississippi River Lake Pontchartrain.
Answer:
Lake pontchartrain
Explanation:
How many grams of phosphorous is in the human skeleton if its average
weight is 11 kg and contains 58% of calcium phosphate (Ca3(PO4)2)?
A 0.00215-g sample of polystyrene, a polymer composed of carbon and hydrogen, produced 0.00726 g of CO2 and 0.00148 g of H2O in a combustion analysis. What is the empirical formula for polystyrene?
Answer:
CH
Explanation:
Polystyrene is composed only by C and H.
We can calculate the number of C moles contained in the original sample mass (0.00215 g), using the produced mass of CO₂:
0.00726 g CO₂ ÷ 44 g/mol = 1.65x10⁻⁴ mol CO₂As 1.65x10⁻⁴ moles of CO₂ were produced, in the polystyrene sample there were 1.65x10⁻⁴ moles of C.
Now we calculate how many moles of H₂O were produced:
0.00148 g H₂O ÷ 18 g/mol = 8.22x10⁻⁵ mol H₂OThe number of H moles produced is double the amount of H₂O moles, so in the polystyrene sample there were 1.64x10⁻⁴ moles of H.
The number of C and H moles are the same, this means the empirical formula is CH.
Which gas will have the least collisions between its particles?
A. Helium at 20 C
B. Oxygen at -45 C
C. Carbon dioxide at 80 C
D. Argon at 265 K
The gas that has the least collisions between its particle is helium at 20° C. The correct option is A.
What is collision?Collision is a term used when two particles or object collides or clash and there is an exchange or transformation of energy between them. When a collision happens, the force is exerted on each other.
Helium is the second most abundant element present in the atmosphere. It is the lightest gas and its particle collides when there is an increase in the temperature.
Thus, the correct option is A. Helium at 20° C., regarding the collision of particles between its particles.
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HELP NEED THIS BADLLLLY !!!!!!!!!
Answer:
2 is correct
Explanation:
My friend for you this answer
In which atmospheric layer is the ozone layer? O stratosphere o thermosphere O mesosphere troposphere
Answer:
The stratosphere
Explanation:
A hot piece of copper was dropped into 155 g of water at 23.6 °C and 2,100 J of energy was transferred to the water. What is the final temperature of the water?
Answer:
26.8 °C
Explanation:
Step 1: Given and required data
Mass of water (m): 155 gEnergy transferred to the water (Q): 2100 JInitial temperature of the water (T₂): 23.6 °CFinal temperature of the water (T₁): ? Specific heat of water (c): 4.184 J/g.°CStep 2: Calculate the final temperature of the water
We will use the following expression.
Q = c × m × (T₂ - T₁)
T₂ = 2100 J/(4.184 J/g.°C) × 155 g + 23.6 °C = 26.8 °C
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CuCl2(aq) + Na3PO4(aq) =>?
Net ionic equation
0.254g lead(ii)ethanoate, on adding excess K2CrO4 solution, gave 0.130g of lead(ii)chromate precipitate. what is the percentage composition of Pb in the organic salt? (O = 16, Cr = 52, Pb = 207).
Answer:
32.8%
Explanation:
All of the Pb⁺² species precipitated as lead(II) cromate, PbCrO₄ (we know this as excess K₂CrO₄ was used).
First we convert 0.130 g of PbCrO₄ into moles, using its molar mass:
0.130 g ÷ 323 g/mol = 4.02x10⁻⁴ mol PbCrO₄There's 1 Pb⁺² mol per PbCrO₄ mol, so in total 4.02x10⁻⁴ moles of Pb⁺² were in the ethanoate sample.
We convert those 4.02x10⁻⁴ moles of Pb into grams:
4.02x10⁻⁴ mol * 207 g/mol = 0.083 g PbFinally we calculate the percentage composition of Pb:
0.083 g Pb / 0.254 g salt * 100% = 32.8%What are two things that interact that determine if there is a phase change or not HELP
Answer:
phase change always has two phases in contact during the change. melting => solid & liquid; evaporation (boiling) => liquid & vapor. If only one phase is present, then phase change is not occurring. Also, when two phases are in contact, no temperature changes occur. Only the pure phase demonstrates temperature change when measured. Example, when ice is added to water, at thermal equilibrium (temp = 0°C) the water temp will not continue to change. Only when all the ice has melted will the water temperature demonstrate a measured temperature change.
Explanation:
What is the first step in this
experiment?
Answer: Cut the card borad
Explanation: