Answer:
electron
Explanation:
How would you prepare 250.0ml of 0.5 M solution from 6 M stock solution of NaCl?
Answer:
I would place 0.5 M solution of the 6.0 stock solution to a 250 mL volumetric flask and then add 250 mL of water.
Explanation:
Something used to represent a complex idea or process in science is a what
Answer:
a model?
Explanation:
im not sure! i think so
Answer:
Yes, It is a model
Explanation:
A complex idea or a process can be demonstarated by using a Model because you can see things easier and its basically a copy of anything from forests to volcanoes but smaller to make it easier to see.
Hope This Helps
Which of the following describes a chemical change?
A. a suspension of corn starch and water
B. formation of a precipitate
C. formation of a solution
D. filtration of a solid from a liquid
Answer:
C
Explanation:
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Enter the symbol of a sodium ion, Na+
N
a
+
, followed by the formula of a sulfate ion, SO42−
S
O
4
2
−
. Separate the ions with a comma only—spaces are not allowed.
Express your answers as ions separated by a comma.
Answer:
Na⁺,SO₄²⁻
Explanation:
Sodium sulfate is formed by the sodium and sulfate ion.
Sodium is present in group one thus it has only one valence electron. Sodium lose its one valence electron to get complete octet and thus form cation with +1 charge.
On other hand sulfate ion is an anion it carries -2 charge so when it react with sodium there are two sodium atom combine with one sulfate ion inorder to make the compound neutral.
2Na + SO₄²⁻ → Na₂SO₄
Sodium sulfate is actually form when sodium react with sulfuric acid and hydrogen gas is liberated.
Chemical equation:
Na + H₂SO₄ → Na₂SO₄ + H₂
Balance chemical equation:
2Na + H₂SO₄ → Na₂SO₄ + H₂
why is earth often referd as a blue planet ?
A-When viewed from space, the biosphere always looks blue.
B-Most people like blue.
C-The sky is blue.
D-The hydrosphere looks blue and covers three-fourths of the Earth’s surface.
NEED ANSWER ASAP
Answer:
D-The hydrosphere looks blue and covers three-fourths of the Earth’s surface.
Explanation:
How might sediment be a good thing?
Answer: Sediment is important because it often enriches the soil with nutrients. Areas rich in sediments are often also rich in biodiversity. Sedimentary soil is usually better for farming. Deltas and river banks, where much sediment is deposited, are often the most fertile agricultural areas in a region.
An atom has 9 electrons and 9 protons at the start. If it loses 2 electrons, the net charge on the atom will be
If it loses 2 electrons, the net charge on the atom will be 2. You should first see if the question is already answered next time.
how many moles of tin (II) fluoride will be produced if 22.9 grams of hydrogen fluoride react
Answer:
From 22.9 g of HF 0.575 moles of tin(II) fluoride are produced.
Explanation:
Given data:
Moles of tin(II) fluoride produced = ?
Mass of hydrogen fluoride react = 22.9 g
Solution:
Chemical equation:
SnO + 2HF → SnF₂ + H₂O
Number of moles of HF:
Number of moles = mass/ molar mass
Number of moles = 22.9 g/ 20 g/mol
Number of moles = 1.15 mol
Now we will compare the moles of SnF₂ with HF.
HF : SnF₂
2 : 1
1.15 : 1/2×1.15 = 0.575 mol
Thus, from 22.9 g of HF 0.575 moles of tin(II) fluoride are produced.
helpppp in a chemical equation, in which direction does the "yields" arrow point, and what factor does it indicate?
It points to the left, toward the reactants.
It points to the left, toward the products.
It points to the right, toward the reactants.
It points to the right, toward the products.
Answer:
It points right, towards the reactants
Explanation:
In a chemical equation, the arrow indicating the yield is to the right towards the arrow. The reactants are written in the left side and the product are written in the right side.
What is a chemical equation?A chemical equation represents the reaction between two or more elements or compound. The reaction describes the chemical combination between atoms.
A general chemical equation representing a chemical reaction is written below:
A + B ⇒ C.
Here, A and B are reactants and C be the product.
The yield of a reaction is the amount of product obtained. The theoretical yield might differ from the actual yield. Therefore, the arrow of a reaction points to the right towards products.
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If you weigh 118 lbs, how many kilograms is this
Answer:
the answer is 53.524 kg
(A) Hemoglobin is 50% saturated (P50) at 20 torr, which is approximately equal to the partial pressure of O2 in muscle. The partial pressure of O2 in the lungs is 100 torr. If the Hill coefficient nh = 3, calculate how efficient hemoglobin is at O2 delivery. Express your answer as the difference between factional O2 binding in the lungs and fractional O2 binding in muscle (qlungs – qmuscle). (B) How would the efficiency of O2 delivery change if hemoglobin were not cooperative (i.e. if nh =1)?
Answer:
Explanation:
Given that:
P₅₀ = 20 torr in muscle
The partial pressure of O2 in lungs Po₂ = 100 torr
The hill coefficient [tex]n_h[/tex] = 3
According to the Hill coefficient;
[tex]\dfrac{\Upsilon}{1-\Upsilon}= (\dfrac{PO_2}{P_{50}})^n[/tex]
here;
[tex]\Upsilon[/tex] = fraction of haemoglobin monomers
[tex]\dfrac{\Upsilon}{1-\Upsilon}= (\dfrac{100}{20})^3[/tex]
[tex]\dfrac{\Upsilon}{1-\Upsilon}[/tex] = 125 θ lungs
However for θ muscle :
[tex](\dfrac{PO_2}{P_{50}})^n=( \dfrac{20}{20})^3[/tex]
= 125 (θ lungs) - 1 (θ muscle)
= 124
B.
if nh =1
[tex]\mathtt {\theta \ lungs} = \dfrac{\Upsilon}{1-\Upsilon}= (\dfrac{100}{20})^1[/tex]
[tex]\mathtt {\theta \ lungs} =5[/tex]
[tex]\mathtt {\theta \ muscle} = \dfrac{20}{20}^1[/tex]
(θ muscle) = 1
(θ lungs) - (θ muscle) = 5 - 1
(θ lungs) - (θ muscle) = 4
A) The efficiency of hemoglobin at O₂ delivery = 124
B) Efficiency of O₂ delivery will change by : 4
Given data:
Partial pressure of O₂ in lungs ( PO₂ ) = 100 torr
Partial pressure of O₂ in muscle = ( P₅₀ ) = 20 torr
Hill coefficient nh = 3
r = fraction of hemoglobin monomers
A) Determine the efficiency of hemoglobin at O₂ delivery
Given that Hill coefficient = [tex]\frac{r}{1-r} = (\frac{PO_{2} }{P_{50} } )^{n}[/tex]
= [tex]\frac{r}{1-r} = (\frac{100}{20})^{3}[/tex] = 125 ∅ Lungs
For Muscle :
[tex](\frac{20}{20} )^{3}[/tex] = 1 ∅ muscle
Therefore the efficiency of hemoglobin at 0₂ delivery
= ( ∅ lungs - ∅ muscle )
= ( 125 - 1 ) = 124
B ) Determine the change in efficiency of O2 delivery
when hill coefficient ( nh ) = 1
for lungs :
[tex]\frac{r}{1-r} = (\frac{100}{20})^{1}[/tex] = 5
for muscle :
[tex](\frac{20}{20} )^{1}[/tex] = 1
Therefore change on efficiency = ( 5 - 1 ) = 4
Hence we can conclude that The efficiency of hemoglobin at O₂ delivery = 124 and Efficiency of O₂ delivery will change by 4
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You add 168.90 grams of NaCl to a container and then you add 616.00 grams of water to that same container What is the weight percent of NaCl in the containerI
Answer:
The weight percent of NaCl in the container is 21.5%
Explanation:
Given that,
Mass of NaCl = 168.90 gram
Mass of water = 616.00 grams
We need to calculate the weight percent of NaCl in the container
Using formula of percentage of weight
[tex]weight\ \%\ of\ component\ of\ the\ solution =\dfrac{weight\ of\ the\ component\ in\ the\ solution}{total\ weight\ of\ the\ solution}\times100[/tex]
Put the value into the formula
[tex]weight\ \%\ of\ component\ of\ the\ solution =\dfrac{168.90}{168.90+616.00}\times100[/tex]
[tex]weight\ \%\ of\ component\ of\ the\ solution=21.5\%[/tex]
Hence, The weight percent of NaCl in the container is 21.5%
7. Baking soda is a common household chemical compound. The chemical formula
NaHCO3 represents the matter needed to produce baking soda. Baking soda is
considered a compound because. WILL GIVE BRAINLIST
What are two ways nitrogen fixation occurs
Explanation:
natural process
biological fixation
Define energy transformation.
Answer:
Enery transformation is when a forn of energy changes into another.
Explanation:
An example of this would be a lamp. The lamp gets its energy through electricity. This electricity is later turned into light energy. Electrical energy to light evegy.
What makes metals, in particular, good conductors of electricity?
A.
the ability of electrons to flow throughout the metal
OB.
the absence of charged particles
O c.
the high temperatures required to break metallic bonds
D.
the presence of positive and negative ions
Answer: I believe the answer is A
Be sure to answer all parts. Consider the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g)ΔH = −198.2 kJ/mol How would the concentrations of SO2, O2, and SO3 at equilibrium change if we were to (a) increase the temperature? [SO2]: The concentration increases. The concentration decreases. There is no change. [O2]: The concentration increases. The concentration decreases. There is no change. [SO3]: The concentration increases. The concentration decreases. There is no change. (b) increase the pressure and decrease the volume? [SO2]: The concentration increases. The concentration decreases. There is no change. [O2]: The concentration increases. The concentration decreases. There is no change. [SO3]: The concentration increases. The concentration decreases. There is no change. (c) add a catalyst? [SO2]: The concentration increases. The concentration decreases. There is no change. [O2]: The concentration increases. The concentration decreases. There is no change. [SO3]: The concentration increases. The concentration decreases. There is no change.
Answer:
a)
[SO2]: The concentration increases
[O2]: The concentration increases.
[SO3]: The concentration decreases.
b)
[SO2]: The concentration decreases.
[O2]: The concentration decreases.
[SO3]: The concentration increases.
c)
[SO2]:There is no change.
[O2]: There is no change.
[SO3]: There is no change
Explanation:
For an exothermic reaction, increase in temperature decreases the concentration of products and increases the concentration of reactants since increase in temperature shifts the equilibrium position to the left hand side.
Increase in pressure and decrease in volume will shift the equilibrium position towards the right hand side which means more SO3 in the system.
Catalyst increases the rate of forward and reverse reaction simultaneously hence at equilibrium, the concentration of reactants and products remain unchanged.
What are the physical properties of chlorine?
Answer:
The Physical Properties of Chlorine are as follows:
Color: Greenish-yellow.
Phase: Gas.
Odor: Disagreeable, suffocating smell.
Density: About two and one-half times as dense as air.
Solubility: Is soluble in water. ...
Boiling Point: The boiling point of chlorine is –34.05°C.
Melting Point: The melting point is –101°C.
Explanation:
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Question 3 of 8
Which two characteristics are needed to describe a force?
A. Direction
B. Speed
C. Resistance
D. Size
SUBT
Answer:A. Direction
C. Resistance
Explanation:
Forces are due to an interaction of at least two objects. It may change the state of motion of an object. It may change the shape of an object. Forces applied on an object in the same direction add to one another and the resultant is in the same direction.
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the valency of nitrogen is 3 . Give reason
Answer:
The nitrogen atom has 5 electrons in the outermost shell, so it can accept 3 electrons to fulfil the octet structure. Therefore the valency of nitrogen is 3.
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Which statement best describes how nearly all rock is formed?
A. Soil gradually hardens beneath Earth's surface
B. A different type of rock is broken down or changes in
in some way
C. Fire, water, or air cools into layers of rock
D. A mixture of minerals separates into several pure minerals.
Answer:
B
Explanation:
The rock cycle is a series of processes that create and transform the types of rocks in Earth’s crust. A different type of rock is broken down or changes in some way. The correct option is B.
What are types of rocks?Sedimentary, igneous, and metamorphic rocks are the three main categories of rocks. Each of these rocks is the result of physical processes that are a part of the rock cycle, such as melting, cooling, eroding, compacting, or deforming.
Rock fragments from other types of existing rocks or organic material are used to create sedimentary rocks. Clastic, organic (biological), and chemical sedimentary rocks are the three different types of sedimentary rocks.
Rocks that have undergone extreme heat or pressure and changed from their initial state are known as metamorphic rocks. When molten, heated material cools and solidifies, igneous rocks are created (their name is derived from the Latin word for fire).
Thus the correct option is B.
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three students measured the volume of water with three different devices they report the volumes
large cylinder 164 ml
small cylinder 39.7 ml
calibrated buret 18.16 ml
if they pour it into a single container what is the volume
Answer:
The total volume of water is 222 ml.
Explanation:
Given that,
Volume of water by different devices are,
First large cylinder =164 ml
Second small cylinder = 39.7 ml
Third calibrated burette = 18.16 ml
We need to calculate the total volume of water
Using given data
volume of total water=volume by large cylinder+volume by small cylinder+volume by calibrated burette
Put the value into the formula
[tex]V_{w}=164+39.7+18.16[/tex]
[tex]V_{w}=221.8\approx 222\ ml[/tex]
Hence, The total volume of water is 222 ml.
adding hot water to your cold bath water is
conduction
convection
radiation
Answer:convection
Explanation:
Answer: B. Convection
Explanation: I hope this helps! :)
Which of the following terms best reflects the process by which humans store memories ?
Answer:
there are no term
Explanation:
what are the term
the object in question 1 has a mass of 21.535g. what metal is the cylinder most likely made of? why? pls help asap!!
Answer:
Aluminium
Explanation:
From the question given above, the following data were obtained:
Diameter (d) = 1.25 cm
Height (h) = 6.48 cm
Volume (V) of cylindrical=.?
Mass (m) of cylindrical object = 21.535 g
Density of the cylindrical object =..?
Next, we shall determine the radius of the cylindrical object. This is illustrated below:
Diameter (d) = 1.25 cm
Radius (r) =?
r = d/2
r = 1.25/2
Radius (r) = 0.625 cm
Next, we shall determine the volume of the cylindrical object. This can be obtained as follow:
Height (h) = 6.48 cm
Radius (r) = 0.625 cm
Pi (π) = 3.14
Volume (V) of cylindrical=.?
V = πr²h
V = 3.14 × 0.625² × 6.48
V = 7.948 cm³
Recall:
1 cm³ = 1 mL
Therefore
7.948 cm³ = 7.948 mL
Thus, the volume of the cylindrical object is 7.948 mL
Finally, we shall determine the metal in which the cylindrical object is made up of by calculating the density of the cylindrical object. This can be obtained as follow:
Mass (m) of cylindrical object = 21.535 g
Volume of the cylindrical object = 7.948 mL
Density of cylindrical object =?
Density = mass /volume
Density = 21.535 / 7.948
Density of cylindrical object = 2.7 g/mL
Comparing the density of the cylindrical object (i.e 2.7 g/mL) with those given in the table in the question, the cylindrical object is made of aluminium since they have the same density.
A protein was previously determined to contain 16.2 wt% nitrogen. A 691 μL aliquot of a solution containing the protein was digested in boiling sulfuric acid. The solution was made basic and the liberated NH3 was collected in 10.00 mL of 0.0390 M HCl . A volume of 4.16 mL of 0.0155 M NaOH was required to react with the excess, unreacted HCl . Calculate the protein concentration of the solution in units of milligrams per milliliter.
Answer:
6.60mg N / mL
Explanation:
All nitrogen is converted in NH₃ that react with the HCl, thus:
NH₃ + HCl → NH₄⁺ + Cl⁻
In the problem, the excess of HCl reacts with NaOH, thus:
HCl + NaOH → NaCl + H₂O
The moles of NaOH = Moles of HCl in excess is:
4.16mL = 4.16x10⁻³L * (0.0155mol / L) = 6.448x10⁻⁵mol HCl in excess
Initial moles of HCl are:
10x10⁻³L * (0.0390mol / L) = 3.9x10⁻⁴moles HCl
That means the moles of HCl that reacts = Moles of NH3 = Moles of N are:
3.9x10⁻⁴ moles - 6.448x10⁻⁵moles = 3.2552x10⁻⁴ moles N.
To convert these moles to grams we need to use molar mass of N = 14.01g/mol:
3.2552x10⁻⁴ moles N * (14.01g/mol) = 4.56x10⁻³g * (1000mg / g) =
4.56mg of N
And volume in mL is:
691 μL * (1mL / 1000μL) = 0.691mL
Concentration in milligrams per mililiter is:
4.56mg N / 0.691mL =
6.60mg N / mL3. True or False. A compound is formed when two or more elements are
False
True
We can see water change state, from ice to steam. This is a ———-
change in matter.
A)
chemical
B)
combustion
C)
physical
D)
solubility
Answer:
C
Explanation:
its physical change.
Students want to gather evidence for the claim that the number of atoms present before a chemical reaction is equal to the number of atoms present after the chemical reaction. They decide to react vinegar and baking soda in a sealed plastic bag. Which of the following would provide evidence the students need
Answer:
The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.
Explanation:
The two main postulates that was given by Antoine Lavoisier are, oxygen play an important role in combustion and the other is mass of the reactant and product is conserved. Therefore, the reaction shows the law of conservation of mass.
What is law of conservation of mass?According to Law of conservation of mass, mass can neither be created nor be destroyed. Mass can only be transformed from one form to another. The law of conservation of mass was given by Antoine Lavoisier.
Every reaction in nature follow the law given by Antoine Lavoisier that is mass is always conserved. The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.
Therefore, the reaction shows the law of conservation of mass.
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Which of the following could result from a substance that undergoes a physical change
Answer:
B. It undergoes phase change.
Explanation: