Answer:
Observes and measure
Explanation:
Answer:
they use tests
Explanation:
they search for evidence using experiments,an experiment is a test to see if their explanation is right or wrong. evidence is made up of observations a scientist makes during an experiment
how many moles are there in a 3.00M solution when you have 1.78L
Adam is doing a science project. He wants to find out how the height of the Sun affects the length of shadows. He will measure the shadow of his house at different times. He will see when the shadow is the longest.
Which is a scientific prediction Adam could make about his project?
A.
The Sun is highest at noon.
B.
The shadow will be longest in the morning.
C.
My shadow is shorter than the shadow of my house.
D.
I found out that the shadow is shortest at noon.
Answer:
d I think there's two answer
Explanation:
or c
So I’m doing 1) which can support more weight : paper or plastic bags? And 2) what paper airplane design flies to furthers
Just give me the CER IF U CAN DO THESE PLEASE ITS DUE SOON !!!
Answer:
Plastic bag.
Explanation:
Plastic bag can hold more weight as compared to paper bag because the plastic bag has more strength which holds more weight. Th paper bag can be tear easily when it physically contact with the water while on the other hand, plastic bag will not tear down and save from it. So due to these features people use plastic bags for carrying materials as compared to other bags.
wht is this called
N which chain does it belong
Answer:
national
Explanation:
I don't understand, I'm sorry
Which equation is an expression of the rate law?
A. PV = nRT
B.
* = AR
C. Rate = K[A]”[B]"
D. Keg
C D
[Al"B
Answer:
The answer to the question is C
The equation which is an expression of the rate law is: Rate = K[A]”[B]". Thus, the correct option will be C.
What is the rate law?A rate law of a chemical equation shows how the rate of a chemical reaction depends on the concentration of reactant molecules. For a chemical reaction such as aA → products, the rate law of the reaction generally has the form rate = k[A]ⁿ, where k is a proportionality constant which is called as the rate constant and n is the order of the reaction with respect to A reactant.
The rate law of a chemical reaction contains only one concentration term which is raised to the first power. Hence the rate constant of a reaction must have units of reciprocal seconds (s⁻¹) to have units of moles per liter per second for the reaction rate: M·s⁻¹ = M/s.
Therefore, the correct option will be C.
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where is reverse osmosis used
Answer:
Reverse osmosis systems find frequent use in the following: Boiler feed-water treatment: used to reduce solids content of waters prior to feeding into boilers for power generation or otherwise.
Explanation:
Can someone please solve this?
Answer:
Indirect (B)
Explanation:
When one facter increases the other decreases.
Answer:
INDIRECT- when one factor increases, the other decreases
A sample of a certain isotope has an initial activity of 40,000 cpm. After 24.8 days, the activity is 2500 cpm. What is the half life of the isotope?
Answer:
6.2 days
Explanation:
initial activity = 40,000 cpm
one half-life = 20,000 cpm
two half-lives = 10,000 cpm
three half-lives= 5,000 cpm
four half-lives = 2500 cpm
24.8 days/4 half-lives = 6.2 days/ half-life
Substance D - It has a high melting and boiling point. The arrangement of its particles are closely packed. It cannot conduct electricity unless molten or dissolved in water. What type of element is substance D?
Answer:
ionic
Explanation:
because when in molten or dissolved in water ions are free to move and carry a charge however when in solid the ions are fixed in position so can't carry a charge.
if 1 mole of Zn reacts xompletely with 1 mole of I2, how many moles of ZnI2 will result?
Answer:
Zn + I₂ ⇒ ZnI₂Explanation:
The result of this reaction is only one mole of ZnI₂.Mole measure the number of elementary entities of a given substance that are present in a given sample. 1 mole of ZnI[tex]_2[/tex] will result by the reaction of 1 mole of Zn with 1 mole of I[tex]_2[/tex].
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number. The stoichiometry represents the number of moles.
The balanced equation is
[tex]Zn+ I_2\rightarrow ZnI2[/tex]
To see the mole of zinc iodide we need to have the knowledge of stoichiometry chemistry. So, the mole ratio among Zn, I[tex]_2[/tex] and [tex]ZnI_2[/tex] are 1:1:1 that means to produce 1 mole of ZnI[tex]_2[/tex], one of each Zn and I[tex]_2[/tex] are required.
Therefore 1 mole of ZnI[tex]_2[/tex] will result by the reaction of 1 mole of Zn with 1 mole of I[tex]_2[/tex].
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What change would increase the amount of solid solute able to be dissolved in liquid water?
The rise in kinetic energy with temperatures allows the solvent molecules to break apart the solute molecules that are held by intermolecular attractions.
What factors affect the solubility of solids in a liquid substance?There are two direct elements that influence solubility are
Temperature and Pressure.Temperature stimulates the solubility of both solids and gases, but the pressure is only concerned with the solubility of gases.
Thus, solids are dissolved in liquid water, the solubility increases with temperature.
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a chemist dissolves 0.564 moles of manganese (IV) oxide (MnO2) in water, and adds enough water to make 0.510 L of solution. Calculate the molarity of the solution.
Answer:
The molarity of the solution is 1.1 [tex]\frac{moles}{liter}[/tex]
Explanation:
Molarity is a measure of the concentration of that substance that is defined as the number of moles of solute divided by the volume of the solution.
The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:
[tex]molarity=\frac{number of moles of solute}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex]
In this case
number of moles of solute= 0.564 molesvolume= 0.510 LReplacing:
[tex]molarity=\frac{0.564 moles}{0.510 L}[/tex]
Solving:
molarity= 1.1 [tex]\frac{moles}{liter}[/tex]
The molarity of the solution is 1.1 [tex]\frac{moles}{liter}[/tex]
-
2
Solid potassium chlorate decomposes to produce solid
potassium chloride and oxygen gas according to the balanced
equation: 2 KCIO
2 KCl + 3 O
What volume of oxygen gas, measured at 40.0°C and 85.4 kPa,
will be produced when 13.5 g of potassium chlorate is
decomposed?
Answer:
5 × 10^-4 L
Explanation:
The equation of the reaction is;
2KClO3 = 2KCl + 3O2
Number of moles of KClO3 = 13.5g/122.5 g / mol = 0.11 moles
From the stoichiometry of the reaction;
2 moles of KClO3 yields 3 moles of O2
0.11 moles of KClO3 yields 0.11 × 3/2 = 0.165 moles of oxygen gas
From the ideal gas equation;
PV= nRT
P= 85.4 × 10^4 KPa
V=?
n= 0.165
R= 8.314 J K-1 mol-1
T= 40+273 = 313K
V= 0.165 ×8.134 × 313/85.4 × 10^4
V=429.4/85.4 × 10^4
V= 5 × 10^-4 L
A mixture of gases with a pressure of 900 mm Hg contains 20% of oxygen and 80% of nitrogen by volumeWhat is the partial pressure of the oxygen gas in the mixture?
A-45mmHg
B-180mmHg
C-210 mmHg
D-320 mmHg
Answer:
180 mmHg
Explanation:
Total volume of gases = 20% + 80%= 100%
Total pressure of gases = 900 mm Hg
Note that partial pressure of a gas = mole fraction × total pressure
Mole fraction of oxygen = 20/100
Hence partial pressure of oxygen= 20/100 × 900 mm Hg
partial pressure of oxygen= 180 mmHg
Which would have a stronger attraction to the nucleus, the outer electrons of a carbon atom, or the outer electrons of an oxygen atom? Why?
Answer: Outer electrons because they revolve around the nucleus and can be multiple more than one
Explanation:
Hope it helps you you
Passive prosthetics came about to meet what need?
A. The need for implanted materials to be biocompatible
B. The need for stronger devices
C. The need for devices to function without an external power source
D. The need for smaller devices
Answer:
c.............. ......
According to the context, passive prosthetics came about to meet the need for devices to function without an external power source.
What are passive prosthetics?They are a group of prosthetics aimed mainly at promoting postural balance and body image.
These external devices can be used to replace the missing or deficient upper limb segment without an external power source.
Therefore, we can conclude that according to the context, passive prosthetics came about to meet the need for devices to function without an external power source.
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What is ppm?
A. Concentration of a solute in grams/106 grams solution
B. Concentration of a solute in mol/L solution
C. Concentration of a solute in mol/kg solvent
D. Concentration of a solute in mol/mol solution
SUBMIT
HURRY!!!!
Answer:
This is an abbreviation for "parts per million" and it also can be expressed as milligrams per liter (mg/L). This measurement is the mass of a chemical or contaminate per unit volume of water. Seeing ppm or mg/L on a lab report means the same thing.
2.98 moles of H2 at 35°C and 2.3 atm are in a 32.8 L container. How many moles of H2 are in a 45.3 L container under the same conditions?
Answer:
4.12 moles
Explanation:
We can solve this problem with the Ideal Gases Law.
P . V = n . R . T
In our first case we have:
P = 2.3 atm
V = 32.8 L
n = 2.98 moles
T → 35°C + 273 = 308K
Let's replace data for the second case:
2.3 atm . 45.3L = n . 0.082 . 308K
n = (2.3 atm . 45.3L) / (0.082 L.atm/mol.K . 308K)
n = 4.12 moles
Answer:
4.11 moles of H₂ are in a 45.3 L container under the same conditions.
Explanation:
Avogadro's law establishes the relationship between the amount of gas and its volume when the temperature and pressure are held constant.
This law says that the volume of a gas under conditions of constant temperature and pressure is directly proportional to the number of moles of gas. That is, if the amount of gas is increased, the volume will increase; whereas if the amount of gas is decreased, the volume decreases.
Avogadro's law is expressed mathematically as the quotient between the volume and the amount of gas equal to a constant:
[tex]\frac{V}{n} =k[/tex]
Being 1 the initial conditions and 2 the final conditions, the following is satisfied:
[tex]\frac{V1}{n1} =\frac{V2}{n2}[/tex]
In this case:
V1= 32.8 Ln1= 2.98 molesV2= 45.3 Ln2= ?Replacing:
[tex]\frac{32.8 L}{2.98 moles} =\frac{45.3 L}{n2}[/tex]
Solving:
[tex]n2*\frac{32.8 L}{2.98 moles} =45.3 L[/tex]
[tex]n2=45.3 L*\frac{2.98 moles}{32.8 L}[/tex]
n2= 4.11 moles
4.11 moles of H₂ are in a 45.3 L container under the same conditions.
Why does water appear blue?
Answer:
Explanation:
Water is blue because water absorbs colors in the red part of the light spectrum. Like a filter, this leaves behind colors in the blue part of the light spectrum for us to see.
Which of the following best describes the bonding found within Al2O3?
Answer:
C). Electrostatic attractions between + and - charged ions.
Explanation:
They're electrostatic attractions because it is electrovalent bonding.
The bond type in alumina Al₂O₃ is described by the option C. Strong strong electrostatic force between positive and negative ions make this ionic compound.
What is alumina ?Alumina is one of the significant mineral of aluminum metal. Aluminum is 13th element in periodic table. Even though it is classified among the nonmetals Al shows metallic properties.
Al is an electropositive element with three valence electrons. Hence, it forms ionic compounds with highly electronegative elements such as oxygen.
Al easily reacts with oxygen to form the compound Al₂O₃. Al donates its two electrons with an oxygen atom at the end and one electron to the intermediate oxygen. The same for the second Al atom. Hence Al acquires +3 charge and O acquires -2 charge which binds them together.
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Which cell part is responsible for energy release?
A. nucleus
B. ribosome
C. mitochondrion
D. Golgi apparatus E. endoplasmic reticulum
Answer:
mitochondria is responsible for energy
A molecule
B compound
C atom
D element
Answer:
D. Element.
Explanation:
Atoms form elements. Elements form molecules. Molecules form compounds.
what happens to an ionic compound when it is dissolved in water?
a: the electrons are combined with the water molecules
b: the ions combine and conduct electricity
c: the ions separate and conduct electricity
d:liquid crystals are formed
Answer:
c
Explanation:
because the ion are Mobil which mean they are free not combined and carry a charge but when they are combined/ fixed in position they can't carry a charge so therefore can't conduct electricity :)
HELP ME WITH THIS CHEMISTRY ILL MARK U THE BRAINLYEST
Answer:
pv=nrt solution re solve it
Help! Pls tell me the meanings of all of these words and please try to make them short as possible!!! tysm have a great day! <3
Answer:
Biofuel: Fuel from living matter
Conservertion of energy: It's a law where energy, when bodies/particles touch in a close system stays constant.
Conduction: Where via touch heat/electricity travels to a diffrent thing.
Which of the following could be predicted using Dmitri Mendeleev's periodic
table?
A. Number of neutrons
B. Atomic number
C. Atomic mass
D. Isotope number
The atomic mass of elements could be predicted using Dmitri Mendeleev's periodic table.
What is the Periodic Table?The Periodic Table of elements is an arrangement of elements in groups and periods based on increasing atomic number.
The first periodic table of elements was designed by Mendeleev.
The arrangement was based on increasing atomic mass of elements.
Therefore, atomic mass of elements could be predicted using Dmitri Mendeleev's periodic table.
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How does the uneven hearing of earth cause convection currents to form?
PLEASE ANSWER:)
Answer:
Because of the tilt of Earth on its axis, Earth's surface and atmosphere are unevenly heated by the Sun. Convection currents form in the atmosphere as warmer air rises and cooler air sinks.
Uneven hearing of earth cause convention currents to form because the Earth's surface and atmosphere are unevenly heated by the Sun
A solution contains 2.38 g of magnesium
chloride, MgCl2, in 500 cm3 of solution.
(a) Calculate the number of moles of
magnesium chloride in 500 cm3 of the
solution.
(b) What is the concentration of
(i) magnesium chloride in mol/dm3;
(ii) chloride ions in g/dm3?
Answer:
a. 0.0250 moles MgCl2
b. i. 0.0500mol MgCl2 / dm3
ii. 3.54g Cl-/dm3
Explanation:
a. In 500cm3, the mass of MgCl2 (Molar mass: 95.211g/mol) is 2.38g. The moles are:
2.38g * (1mol / 95.211g) = 0.0250 moles MgCl2
b. The dm3 are (1000cm3 = 1dm3):
500cm3 * (1dm3 / 1000cm3) = 0.500dm3
Concentration is:
0.0250 moles MgCl2 / 0.500dm3
i. 0.0500mol MgCl2 / dm3
ii. Moles Cl-:
0.0250 moles MgCl2 * (2mol Cl- / 1mol MgCl2) = 0.0500 moles Cl-
Mass Cl- -Molar mass: 35.45g/mol-:
0.0500 moles Cl- * (35.45g / mol) = 1.77g of chloride ions
1.77g Cl- / 0.500dm3:
3.54g Cl-/dm3
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