a student walks 3.0 hours and travels 6.0km what is the averge speed
Answer:
2.0 km/hr
Explanation:
6.0 km/3.0 hrs
= 2.0 km/hr
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true or false: u find soil rich in humus in horizon c
Answer:
True
Explanation:
What is the energy of a photon with a 6 micrometer wavelength (1 m = 10^6micrometers)?
O 3 x 10-34 )
O 3 x 10-32
O 3 x 10-20 ]
O 3 x 10-20 j
The energy of a photon : 3 x 10⁺²⁰
Further explanationRadiation energy is absorbed by photons
The energy in one photon can be formulated as
[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]
Where
h = Planck's constant (6,626.10⁻³⁴ Js)
f = Frequency of electromagnetic waves
f = c / λ
c = speed of light
= 3.10⁸
λ = wavelength
Wavelength of photon=λ=6 μm = 6.10⁻⁶ m
[tex]\tt E=h\times \dfrac{c}{\lambda}\\\\E=6,626.10^{-34}\times \dfrac{3.10^8}{6.10^{-6}}\\\\E=3.3\times 10^{-20}~J[/tex]
How many grams of solid lithium hydroxide must be used to prepare 450
mL of 0.55M LiOH solution?
Answer:
Mass = 6.706 g
Explanation:
Given data:
Mass of lithium hydroxide = ?
Volume of lithium hydroxide = 450 mL (450/1000 = 0.450 L)
Molarity of lithium hydroxide = 0.55 M
Solution:
Formula:
Molarity = number of moles / volume in L
0.55 M = number of moles / 0.450 L
Number of moles = 0.55 M × 0.450 L
Number of moles = 0.25 mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 0.25 mol × 23.95 g/mol
Mass = 6.706 g
Once the food reaches the esophagus in the digestive system, the biggest difference between the frog and the human digestive system is that after the large intestine, waste is eliminated through the
Answer:
The rectum
Explanation:
what is the chloride anion
Answer:
Cl-
Explanation:
When chlorine reacts with other substances, it usually forms the chloride ion (Cl-). This is because it has seven valence electrons, and in order to gain a full octet, it has to gain one electron (which has a negative charge). For example, when it reacts with Sodium (Na), the product is table salt (NaCl) because chlorine takes one electron from sodium and becomes Cl-. Sodium also becomes Na+, because it loses one electron.
The solubility of potassium chloride is 34 g KCl
100 g H2O
at 20C. What is the maximum amount of KCl that can
dissolve in 200 g of water at 20C?
Answer: When 20 grams of potassium chlorate, KClO3, is dissolved in 100 grams of water at 80 ºC, the solution can be correctly described as:, unsaturated
At approximately what temperature does the solubility of sodium chloride, NaCl, match the solubility of potassium dichromate, K2Cr2O7?, 60 ºC
Explanation:
Which of the following elements has the largest atomic radius (brainliest for right answer)
Aluminum
Silicon
Phosphorus
Sulfer
Chlorine
Complete Symbols
Find each of these:
a) number of protons
b) number of neutrons
c) number of electrons
d) atomic number
e) mass Number
80Br35
Answer: a) 35 , b) 45 , c) 35 , d) 35 , e) 80
Explanation:
a) - protons equal to atomic number of element , b) - subtract atomic number by number of protons to get neutrons (80 - 35 = 45) , c) - protons same as electrons unless its an ion , d) - atomic number is equal to protons , e) - protons plus neutrons equal mass number (35 + 45 = 80). :)
Why did it take 2,000 years for scientists to confirm some of Democritus's ideas about?
Answer:
Explanation:
because it took that long for them to think of one.
Which layer will be the ether layer in a separatory funnel containing diethyl ether and a saturated aqueous solution of nacl?.
The bottom layer will be the ether layer
a mixture in which the solute dissolves until it is no longer able to do so, leaving the undissolved components at the bottom. Solution without saturation. a solution that totally dissolves and leaves nothing behind (but has less solute than the saturated solution) A saturated solution is one that has as much of the solute present as is capable of dissolving. A solution is said to be unsaturated if it doesn't contain all of the solute that can dissolve in it. A saturated solution is one that has as much solute in it as can be dissolved under the circumstances under which it is present.
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which two sentences taken together provide the best evidence to support the ideas that both physical and chemical change can significantly change the appearance of a substance ?
A. in a physical change the material involved is structurally the same before and after the change
B. a piece of metal may be heated in a fire until it glows but the metal is the same material before Heating and after Cooling
C. chemical changes require the breaking and forming of chemical bonds during a chemical reaction
D. the creation of a new ,solid substance from to liquid substance into the kids that a reaction has taken place that has alerted the original substance
Answer:
A ithink
Explanation:
The chemical changes require the breaking and forming of chemical bonds during a chemical reaction. The correct option is C.
What is chemical bond?Chemical Bonding refers to the formation of a chemical bond between two or more atoms, molecules, or ions to give rise to a chemical compound.
These chemical bonds are what hold the atoms in the resulting compound together.
A chemical bond is a bond formed when the atoms in a compound's molecule combine and are held together by a strong combining force.
Chemical bonds are classified into two types namely ionic bonds and covalent bonds.
Chemical bonding enables scientists to combine the elements of the periodic table in a variety of ways to create chemical compounds and materials.
Thus, the correct option is C.
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Another element, Z, in the same period of the Periodic Table as A, reacts with chlorine to
form a compound with empirical formula ZCl 2. The percentage composition by mass of ZCl 2
is Z, 31.13; Cl , 68.87.
Calculate the relative atomic mass, Ar, of Z.
The relative atomic mass, Ar, of the element Z is 32.1.
What is the relative atomic mass of the element Z?The relative atomic mass of the element Z is determined as follows:
compound formed between Z and Cl is ZCl₂
This implies that Z is an element in group 2A of the periodic table
percentage composition by mass of the elements in ZCl₂ are given as follows: Z = 31.13; Cl = 68.87
atomic mass of Cl = 35.5
mass of Cl in the compound = 35.5 * 2 = 71.0
68.87% of the compound has a mass = 71.0 g
mass of the compound (100%) ZCl₂ = 71.0 * 100/68.87
mass of the compound ZCl₂ = 103.1
Relative atomic mass, Ar, of Z = 103.1 - 71
Relative atomic mass, Ar, of Z = 32.1
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Which object has unbalanced forces acting on it?
A leaf falling to the ground
A sweater on a store shelf
A fence around a garden
A letter in a mailbox
Answer:
A leaf falling to the ground.
Explanation:
The leaf is the only object in motion and is falling therefore the force of gravity is the unbalanced force.
what is the mass of 3.01 x 10^21 atoms of Co
Answer:
0.295 g Co
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
3.01 × 10²¹ atoms Co
Step 2: Identify Conversions
Avogadro's Number
Molar Mass of Co - 58.93 g/mol
Step 3: Convert
[tex]3.01 \cdot 10^{21} \ atoms \ Co(\frac{1 \ mol \ Co}{6.022 \cdot 10^{23} \ atoms \ Co} )(\frac{58.93 \ g \ Co}{1 \ mol \ Co} )[/tex] = 0.294552 g Co
Step 4: Check
We are given 3 sig figs. Follow sig fig rules and round.
0.294552 g Co ≈ 0.295 g Co
Write an expression that evaluates to true if and only if the string variable s equals the string end.
Answer:
Declare a variable populationChange, suitable for holding numbers like -593142 and 8930522.
int populationChange
whoever answers this first gets brainly
Answer:
A option
Explanation:
water gets split in photosynthesis
1 Volume of certain amount of a gas at 25°C and
100 cm Hg pressure is 80 mL. The gas is
expanded to 160 mL keeping the temperature
constant. Calculate the pressure of the expanded
Numericals based on Boyle's law
Answer:
P₂ = 50 mmHg
Explanation:
Given data:
Initial volume of gas = 80 mL
Initial pressure of gas = 100 mmHg
Final volume = 160 mL
Final pressure = ?
Temperature = constant
Solution:
The given problem will be solved through the Boyle's law,
"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"
Mathematical expression:
P₁V₁ = P₂V₂
P₁ = Initial pressure
V₁ = initial volume
P₂ = final pressure
V₂ = final volume
Now we will put the values in formula,
P₁V₁ = P₂V₂
100 mmHg × 80 mL = P₂ × 160 mL
P₂ = 8000 mmHg. mL/ 160 mL
P₂ = 50 mmHg
What is an alkaline earth metal that has 5 shells?
Answer:
The elements in the alkaline earth metals group; beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra), have two electrons in their outer electronic shell.
Explanation:
The alkaline earth metals consisted of 5 shells have been beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
The alkali earth metal has been the element of group 2. The elements have consisted of the 2 valence electrons.
The electrons in the elements have been assigned the electron address based on the capacity of the shells to occupy electrons.
The electrons have been filled based on the energy level of the shells.
The order of the increasing energy level has been:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s.
The elements with the occupied 4p shells will have the 5 shells.
The elements in group 2 consisted of 5 shells have been beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
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HELP! why is the aqueous environment of a cell important?
it prevents organelles in a cell from sticking together.
it allows cells to bend and change shape as needed.
it provides a constant energy source for a cell.
it's required for all chemical reactions in a cell.
The aqueous environment of a cell is important because it allows cells to bend and change shape as needed (Option B).
What is the cell aqueous environment?The cell aqueous environment is the surrounding medium which is required for the cell to perform its metabolic activities and whose solute concentration allows the cell to change its shape depending on external stimuli such as glucose level.
In conclusion, the aqueous environment of a cell is important because it allows cells to bend and change shape as needed (Option B).
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Answer: it's required for all chemical reactions in a cell.
Explanation: took the test. please vote :-)
Chemical ____ are used to represent compounds
Answer:
Its formula :)
Explanation:
hope this helps <3
8. What is a quasar?
the mass number of an atom is 15, and its atomic number is 7. the atom probably has... the mass number of an atom is 15, and its atomic number is 7. the atom probably has... at least 15 electrons. 7 electrons in the nucleus. 7 units of negative charge in the nucleus. 8 neutrons in the nucleus. about as much mass in electrons as in protons.
The atom probably has 8 neutrons in the nucleus.
Atomic number (Z) is total number of protons and mass number (A) is total number of protons and neutrons in a nucleus.
N(p⁺) = Z = 7; number of protons in the atom
A = N(p⁺) + N(n°)
N(n°) = A - N(p⁺)
N(n°) = 15 - 7
N(n°) = 8; number of neutrons in the atom
N(e-) = N(p⁺) = 7; number of electrons in the atom
Neutron (symbol: n°) is a subatomic particle with no net electric charge.
Protons and neutrons are found in nucleus of an atom (atomic nuclei).
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FECl3+3NaOH=Fe(OH)3+NaCl
A. Synthesis
B. Decomposition
C. Combustion
D. Single Replacement
E. Double Replacement
Candi uses wires to connect a battery to a light bulb. She knows she has made a complete circuit because the light bulb lights up.
Candi's teacher gives her a wire that has a lot more resistance than the wires she used at first. Candi removes one of the original wires from her circuit and puts the high-resistance wire in its place. What effect will this most likely have on the circuit?
A.
Less current will flow, so the light bulb will be dimmer.
B.
More current will flow, so the light bulb will be brighter.
C.
The battery will have more voltage, so the light bulb will be brighter.
D.
The battery will have less voltage, so the light bulb will be dimmer.
What is needed for a wind farm to be effective
Answer:
for a effective wind farm you would need wind turbines a windy area a rotation powered generator and something to use it on
Explanation:
Which question can be used to identify a physical property of an element?
Does a magnet attract the element?
Does rust form when the element is exposed to oxygen?
Do bubbles form when the element is mixed with an acid?
Does the element burn when held over a Bunsen burner flame?
Answer:
Does a magnet attract the element?
Explanation:
This is because, the attraction of an element by a magnet is a purely physical property. It has to do with the orientation of the electrons in the element. It does not tell us of the composition of the element or how it reacts with other elements. Whereas, the other questions deal with the chemical properties of the element. That is, how it reacts with other elements or substances.
The pH of a solution is 7.0.
What is the pOH?
Enter
Answer:
4 i think
Explanation:
Wher do most living thing get the energy they need for life
Answer:
Earth
Explanation:
Which compound is covalently bonded?
Select one:
a. Al2O3 b. Fe2O3 c. SO2 d. CuCl2
Answer:
The answer is D-CuCl2
I hope this helps
Answer:
D.
CuCl2
Explanation:
May it will help you.