Answer:
a scientific question
Procedure
Conclusion.
Explanation:
Scientific investigation is usually carried out to explain and give answers to natural phenomenon. Now, this scientific investigation is performed through the three main types as described in the question.
With that being said, the most common parts of all types of investigation are :
1. Scientific question: In this stage, questions are usually asked on the basis of observation made which could be answered.
2. Procedure: In this stage, the dimension of the steps are followed to answer and test the scientific question.
3. Conclusion: This is the primary aim that we check when done with our sample values
You are a chemist working in your laboratory. In your storage closet you have a
cabinet that holds only samples of pure elements, no compounds. While looking for a
sample of lithium (LI), you notice that the label on one bottle has worn off. The room is
at normal temperature. The contents of the bottle are liquid and do not look metallic.
What element should you relabel the bottle as?
A.Helium
B.Bromine
C.Arsenic
D.Chlorine
Un medicamento corresponde a una disolución de "nafazolina" (sustancia activa) en agua purificada, en una concentración de 12% V/V. - EXPLICA cuánto soluto hay por cada 100mL del medicamento.
Answer:
12 mL
Explanation:
Según la pregunta;
V / V% concentración del fármaco = 12%
volumen de la solución = 100 ml
De;
V / V% = volumen de fármaco / volumen de solución
volumen de fármaco = V / V% × volumen de solución
volumen de fármaco = 12/100 × 100
= 12 mL
In the SI system of units, the mole is one of seven base units. It is frequently used in chemical calculations. However, a mole of something is just a particular quantity of it. It is not a unit of measure in the way that meters, seconds, and kilograms are. Calculations performed with the number of moles of a substance could also be performed with the number of particles of a substance. Based on this information, do you think that the mole should be considered a base unit in the SI system? Explain why or why not.
The international system of units is known as SI and is a metric system. Mostly used as a system of measurement. It is used in science, technology, and nearly in every part of the country. The system includes coherent units known as derived units.
A mole is not a base unit or any property of the units. It can be used for physical and chemical comparison and hence the mole of substance can be performed with the number of particles of the substance.Hence the option B is correct.
Learn more about the frequently used in chemical calculations.
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Can anyone answer these 4 questions?
Answer:
1. Na2CO3 + 2HCl --> 2NaCl + CO2 + H2O
2. 2NaOH + H2SO4 --> Na2SO4 + H2O
3. CaCO3 + 2HCl --> CaCl2 + CO2 + H2O
4. 4Na + O2 --> 2Na2O
What would you need to do to calculate the molality of 10 mol of NaCl in 200
mol of water?
A. Convert the 10 mol of NaCl to kilograms of NaCl.
O B. Convert the 200 mol of water to liters of water.
C. Convert the 200 mol of water to kilograms of water.
D. Convert the 10 mol of NaCl to grams of NaCl.
Calculate the volume (in L) occupied by 3.40 g of NH3 at STP. (STP: 0 degree Celsius and 1 atmosphere of pressure).
Answer:
Calculate the volume (in L) occupied by 3.40 g of NH3 at STP. (STP: 0 degree Celsius and 1 atmosphere of pressure).
Explanation:
To get the volume of ammonia gas at STP, calculate the number of moles of [tex]NH_3[/tex] in the given amount.
Number of moles of [tex]NH_3[/tex] gas is:
[tex]number of moles of NH_3 gas&=\frac{given mass of the gas}{its molecular mass} \\ &=\frac{3.40g}{17.0g/mol} \\&=0.2 mol.[/tex]
Since,
1 mol of any gas at STP occupies ------- 22.4 L of volume.
then,
0.2 mol of [tex]NH_3[/tex] occupies how much volume?
[tex]=>0.2 mol x \frac{22.4 L}{ 1.0 mol} \\=4.48 L[/tex]
Hence, the volume occupied by 3.40 g of ammonia at STP is --- 4.48 L.
HELPPPPPPPP i accidentally pressed on c
Answer:
a
Explanation:
I'm not completely sure tho veary sorry if it's wrong
Answer:
the answer is C
Explanation:
as the yeast feeds on sugar and yields the ATP per glucose molecule and Carbon dioxide
ASAAPPP NEED HELP IF ANYONE IS AROUND
i. Using carbon skeletal notation, write the dehydration-condensation reaction that occurs between ethanol and butanoic acid.
ii. What is the name of this ester?
Answer:
In the esterification reaction, an OH from the molecule acid and H from the alcohol form a molecule of water.
Ethanol and butanoic acid forms ethyl butanoate
How many ATOMS of boron are present in 3.61 grams of boron trifluoride ?
Answer:
To determine the number of atoms of Boron that are present within 3.61 grams of Boron Trifluoride, it would be best to convert the grams to moles of the compound and then after that use the Avogadro's number to determine the number of molecules and then use the 1 to 3 ratio to determine the total number of Boron atoms.
explain why the boiling point of aluminum is higher than sodium
Explanation:
this is the reason why aluminium's boiling point is higher than that of sodium. sodium forms Na+ ions, therefore 1 electron is lost from each sodium atom, whereas aluminium forms Al3+ ions, so 3 electrons are lost for each Aluminum atom. The number of delocalised electrons therefore increases from sodium to aluminium, and charge density of the ions increases as the ionic charge increases and size decreases.
1) The percentage of oxygen in dry air is _______
A. 0.1
B. 1.0
C. 21
D. 79
2) The composition of the Earth’s earliest atmosphere was different to that of the present atmosphere. Which of these gases was present in large amounts in the Earth’s earliest atmosphere?
A. Oxygen
B. Carbon dioxide
C. Ammonia
D. Nitrogen
Answer:
1) The percentage of oxygen in dry air is _______
C. 21
2) The composition of the Earth’s earliest atmosphere was different to that of the present atmosphere. Which of these gases was present in large amounts in the Earth’s earliest atmosphere?
B. CARBON DIOXIDE
Hope it helps
have a nice day
Answer: The percentage of oxygen in dry air is . 21
Explanation: Ammonia gases was present in large amounts in the easth7s earliest atmosphere
Hope it will help you
How many cm3 in a L?
In this equation, what does n represent?
OA number of electrons in the cell
OB number of electrons in the reactants
OC number of moles of electrons transferred
OD number of products in the equation
OE number of reactants in the quotient
Answer:
the number of electrons in the cell
If charge on only one object is tripled, determine the new force between them:
Answer:
+3·F
Explanation:
The number of objects in the given system = 2 objects
The charge on each object are; q₁ = -Q, q₂ = -Q
The force acting between the objects = +F
The distance between the objects = 2·d
The formula for the force acting between two charged particles is given as follows;
[tex]F=K \times \dfrac{q_{1} \times q_{2}}{r^{2}}[/tex]
Therefore, we get;
[tex]F=K \times \dfrac{-Q \times -Q}{(2\cdot d)^{2}} = K \times \dfrac{Q^2}{4 \cdot d^2}[/tex]
By tripling the charge, q₁, on the first object, we get;
q₂ = 3 × (-Q)
[tex]F_2=K \times \dfrac{-3 \cdot Q \times -Q}{(2\cdot d)^{2}} = K \times \dfrac{3 \cdot Q^2}{4 \cdot d^2} = 3 \times +F = +3\cdot F[/tex]
Therefore, the new force between them, F₂ = +3·F
Help me guys ☹️please
Answer:
Coriolis Effect
Explanation:
The Coriolis Effect is caused by Earths rotation. We can not only see this affecting how winds move, but also where storms form and the movement of oceans currents.
The mass of a boy is 60 kg. Calculate his weight if the value of g is 9.8 ms2
Answer:
Weight = mass × gravitational
Weight = 60 kg × 9.8 ms²
= 588 N
Explanation:
hope it helps
Weight of the boy = Mass of the boy × g
= 60 × 9.8
= 588kgm/s²
= 588N
what is the atomic number of an atom that has 20 protons and 20 neutrons
Answer:
20
Explanation:
Hi there!
We need to find the atomic number of an atom that has 20 protons and 20 neutrons
the atomic number of an atom is equivalent to the amount of protons an atom has, as the number of protons determines what element an atom is.
Since the atom has 20 protons, the atomic number of the said atom is 20
Hope this helps!
Hematite is a naturally occurring mineral and a common form of iron ore. The following statements describe physical and chemical changes occurring to hematite. Which statement describes a chemical change?
When the hematite particles rearrange to form a new substance", this statement describes chemical change.
What is chemical change ?A chemical change is a change of materials into another, new materials with different properties and one or more than one new substances are formed.
As a chemical changes is usually a change where a substance undergoes a chemical change and forms a new substance; which cannot be easily reversed into reactants by any simple physical methods.
In this example the hematite ore forms a new substance by an irreversible chemical change.
Hence, "The hematite particles rearrange to form a new substance", this statement describes chemical change.
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Glycerin, , is a nonvolatile liquid. What is the vapor pressure of a solution made by adding glycerin to at
Complete question is;
Glycerin, C3H8O3, is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 164 g glycerin to 338 mL H2O at 39.8°C?
The vapor pressure of pure water at 39.8°C is 54.74 torr and its density is 0.0992 g/cm³
Answer:
28 torr
Explanation:
Let's first find the number of moles of water in 338 mL.
Molar mass of water = 18 g/mole
Formula for number of moles = mass/molar mass.
Mass = density × volume = 0.0992 × 338 = 33.5296 g
Thus;
Number of moles = 33.5296/18 = 1.863 moles.
Let's use the same procedure to find the Number of moles of glycerine.
Molar mass of glycerine from online values = 92.1 g/mol
Thus;
n_glycerine = (mass)/92.1
We have mass and density as 164 g and 0.0992 g/cm³ respectively.
n_glycerine = 164/92.1
n_glycerine = 1.78
Total moles of solution = 1.863 + 1.78 = 3.643 moles
We are told that The vapor pressure of pure water at 39.8°C is 54.74 torr
Thus, since water dominates, then vapour pressure of solution = (1.863/3.643) × 54.74 ≈ 28 torr
If 14.7 cm3 of alcohol is present in 70 cm 3 of its aqueous solution, the percentage by volume of alcohol will be?
Answer: The percentage by volume of alcohol will be 21%.
Explanation:
Given: Volume of solute = 14.7 [tex]cm^{3}[/tex]
Volume of solvent = 70 [tex]cm^{3}[/tex]
Formula used to calculate percentage by volume is as follows.
[tex]Percentage volume = \frac{volume of solute}{volume of solvent} \times 100[/tex]
Substitute the values into above formula as follows.
[tex]Percentage volume = \frac{volume of solute}{volume of solvent} \times 100\\= \frac{14.7 cm^{3}}{70 cm^{3}} \times 100\\= 21 percent[/tex]
Thus, we can conclude that the percentage by volume of alcohol will be 21%.
Which of the following correctly describes a compound?
A. The atoms are chemically bonded together, and they retain their individual physical and chemical properties.
B.The atoms are not chemically bonded, and there is no set ratio for how the atoms can combine together.
C. The atoms can only combine in fixed ratios, and they can only be separated by a chemical change.
D. The atoms do not retain their individual chemical properties, and they can be separated by physical means.
Answer:
according to me its c part which is correct
5.34x10 to the 27th power molecules of sulfur hexafluoride to moles of sulfur hexafluoride
Answer:
8.87 × 10³ moles.
Explanation:
To convert number of molecules of sulfur hexafluoride (SF6) to moles (n), we divide by Avogadro's number (6.02 × 10²³)
That is; n = N ÷ nA
According to the question, 5.34 x 10^27 molecules of SF6 was given in this question. Hence, the number of moles it contains is given as:
n = 5.34 x 10^27 ÷ 6.02 × 10²³
n = 5.34/6.02 × 10^ (27-23)
n = 0.887 × 10⁴
n = 8.87 × 10³ moles.
HELP ASAP!! PLEASE !!
Answer:
8,3, 7,7
Explanation:
.
Unlike a theory, a scientific law describes an observed pattern without attempting to _____ it.
explain
prove
test
verify
Why do strong bonds exist between water molecules?
They have nonpolar structure.
They are held together by hydrogen bonds.
The hydrogen end of a water molecule is weakly negative.
The shared electrons are more attracted to the hydrogen atom.
Answer: they are held together by hydrogen bonds I believe
Explanation:
The strong bonds exist between water molecules.Because they are held together by hydrogen bonds. Option B is correct.
What is a hydrogen bond?Hydrogen bonding is a bond between hydrogen atom, but rather a sort of dipole-dipole attraction between molecules.
The attractive force between a hydrogen atom covalently bound to a very electronegative atom such as an N, O, or F atom and another extremely electronegative atom causes it.
The strong bonds exist between water molecules.Because they are held together by hydrogen bonds. Hence,option B is correct.
Hence,option B is correct.
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For a reaction, AH = 176 kJ/mol and A SO = 0.285 kJ/(K•mol). At what
temperatures is this reaction spontaneous?
A. At no temperature
B. T< 50 K
C. T> 617 K
D. T< 617K
Help me and I'll make u Brainliest eat and follow u
19. place moth balls in the closet and observe after several days.
20. whenever wax or a candle burns it turns from solid to liquid but again at room temperature it turns to solid
21. evaporation, condensation, precipitation
22. it produces new substances
23. vinegar Bubbles when baking soda is added
24. steam
Place the steps of the action potential in order.
- a brief reversal of membrane potential that travels along the axon
- mechanism that restores the resting membrane voltage and intracellular ionic concentrations
- reversal of the resting potential due to an influx of sodium ions
- period during which potassium ions are diffusing out of the neuron because of a change in membrane permeability
Answer:
-Reversal of the resting potential due to influx of sodium ions
-Mechanism that restores the resting membrane voltage and intracellular ionic concentrations
-Period during which potassium ions are diffusing out of the neuron because of a change in membrane permeability
-A brief reversal of membrane potential that travels along the axon
Explanation:
An action potential is a situation where the membrane potential is briefly reversed from -70mV to +30 mV
There are three steps of the moving action potential, including;
1) The depolarization step, where the membrane resting potential is reversed by the rush of sodium ions into a neuron
2) The repolarization, due to the closing of the voltage-gated sodium channels and the opening of the potassium channels, which is a mechanism that restores the membrane's resting voltage and the ionic concentration in the cell
3) Hyperpolarization, where due to some open potassium channels, there is an increased potassium permeability, and excessive efflux of potassium ions take place, which results in a dip in the membrane potential
4) The above three phases describe the phase of the action potential which is the brief reversal of membrane potential that travels along the axon
Heat is most closely related to which kind of energy?
O nuclear
electrical
thermal
chemical
Answer:
C thermal
Explanation:
 Help ASAP only right answers only no spam don’t answer if you don’t know
i know the answer is a theory
