The question is incomplete, the complete question is;
A chemist is identifying an unknown solid substance that appears purple in color. Upon close inspection with a hand lens, she notices tiny grains in the substance. Some of the grains are blue; other grains are red. Based on this information, the substance is most likely a
a. Compound
b. Homogeneous Mixture
c. Pure substance
d. solution
e. heterogeneous mixture
Answer:
heterogeneous mixture
Explanation:
A heterogeneous mixture simply means a mixture of two different substances. If two substances are the same, they are expected to have the same colour or appearance.
We were told in the question that the colour of the mixture appeared purple. On close examination, the sample was found to comprise of two different substances of different colours; blue and red.
If there are two substances of different colours present in the sample, it then follows that the sample is a heterogeneous mixture.
The table shows the conditions during two trials of a reaction.
Answer:
The correct option is;
The reaction pathway for the trials is different
Explanation:
The effect of a catalyst in a chemical reaction is to increase the rate of a reaction by changing the pathway or mechanism of the reaction and/or to lower the transition state's energy thereby lowering the activation energy of the reaction
The pathway of the reaction is changed by the catalyst by the formation of intermediate compounds by the catalyst which require lower activation energy to form the products than the original non-catalyzed reactants. In the process the catalyst is regenerated, thereby, not taking part in the reaction.
The equilibrium concentrations for the reaction between SO2 and O2 to form SO3 at a certain temperature are given in the table below. Determine the equilibrium constant and whether the reaction favors reactants, products, or neither at this temperature.
Answer:
Option B. K = 1.3×10⁴, product favored
Explanation:
Data obtained from the question include:
O2(g) + 2SO2(g) <==> 2SO3(g)
Concentration of O2, [O2] = 0.024 M
Concentration of SO2, [SO2] = 0.015 M
Concentration of SO3, [SO3] = 0.26 M
Equilibrium constant, K =..?
The equilibrium constant, K is simply defined as the ratio of the concentration of products raised to their coefficient to the concentration of the reactants raised to their coefficient.
The equilibrium constant for the above reaction can be written as
K = [SO3]² / [O2] [SO2]²
Inputing the values of [SO3], [O2] and [SO2] the equilibrium constant, K is:
K = [SO3]² / [O2] [SO2]²
K = 0.26² / 0.024 × 0.015²
K = 1.3×10⁴
Therefore, the equilibrium constant K is 1.3×10⁴.
Since the value of the equilibrium constant, K is large and positive, therefore, the reaction favours the product.
Julie finds a snail on the sidewalk and wants to know whether or not the snail moves throughout the day. She places a
single mark on the sidewalk next to the snail.
What will Julie use the mark for initially?
determining how fast the snail moves
acting as a standard unit of measure
determining the displacement of the snail
O acting as a reference point for detecting motion
The single mark placed on the sidewalk by Julie has been acting as the reference point for detecting the motion of the snail. Thus, option D is correct.
The snail has been the shelled animal that has been mostly residing in the resting condition with limited movement. To evaluate the movement of the snail, there has been the consideration of a point that was the starting point from the movement.
The line that has been set across the sidewalk has been acting as the reference, and the distance traveled has been calculated from that point. Thus, option D is correct.
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What do neurons and protons have in common?
Answer:
Protons and neutrons have almost the same mass and are both located in the nucleus of the atom
Answer:
Protons and neutrons have almost the same mass and are both located in the nucleus of the atom. Protons are charged particles. Neutrons are neutral particles. ... The positive charge of the protons in the nucleus is balanced by the negative charge of the electrons.
The formula for sodium phosphate: NaPO4 Na(PO4)3 Na3PO4
Answer:
Na3 Po4
Explanation:
Na+1
Na+1
Na+1 = Na3
Po4 =
Na3Po4
Na[tex]_3[/tex]Po[tex]_4[/tex] is the formula for sodium phosphate. Sodium phosphates have a wide range of uses in food and water treatment.
What is sodium phosphate?Sodium phosphate is indeed a catch-all phrase for a number of sodium (Na+) as well as phosphate (PO43) salts. Phosphate also forms di-, tri-, tetra-, as well as polyphosphate families or condensed anions. The majority of these salts exist across both anhydrous (water-free) as well as hydrated forms. Hydrates are more prevalent than anhydrous forms.
Sodium phosphates have a wide range of uses in food and water treatment. Sodium phosphates, for example, are frequently employed particularly emulsifying agent (as in processed cheese), smoothing agents, especially leavening agents in baked products. Na[tex]_3[/tex]Po[tex]_4[/tex] is the formula for sodium phosphate.
Therefore, Na[tex]_3[/tex]Po[tex]_4[/tex] is the formula for sodium phosphate.
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Why are the oxidation and reduction half-reactions separated in an
electrochemical cell?
Answer:
It makes the current viable enough to pass through an exterior wire.Explanation:
Electrochemical cells primarily comprise of two half-cells. These half-cells assist in isolating the oxidation and reduction half-reactions. These two reactions are linked by a wire which allows the current to move from one edge to the other. The oxidation at the anode and the reduction take place at the cathode and the addition of a salt bridge helps in completing the circuit and permits the current to flow and leads to the generation of electricity.
The graph compares the kinetic energies of the molecules in four gas samples. Each graph shows a normal distribution, so the average is the center. Which sample is likely to have the lowest temperature? (1 point) A B C D
Answer:
d
Explanation:
i got it right
Gas A is likely to have the lowest temperature. Hence, option A is correct.
What are molecules?The smallest particle of a substance has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms.
In a gas, the kinetic energy is directly proportional to the temperature under constant pressure and volume.
As you can see in the problem, the average of A has low kinetic energy. But the average is increasing between B, C and D.
As gas A has the lowest average kinetic energy:
Gas A is likely to have the lowest temperature
Hence, option A is correct.
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A molecule of chlorine has atoms of the same element, and a molecule of carbon dioxide has different kinds of atoms. Based on this information, chlorine is and carbon dioxide is .
Answer:
chlorine is element and carbon dioxide is compound
Answer:
The correct answer would be that Chlorine is an Element and Dioxide is an Compound.
name all the period 2 elements in mendeleevs periodic table
Answer:
beryllium, magnesium, calcium, strontium, barium, radium
Explanation:
glad to help
Cuantos gramos de sulfato de plomo (II) se requieren para preparar 200mL una solución de esta sal a una concentración de 100 ppm. Si se toma una muestra de 30 mL de la disolución anterior y se diluye en 1000 mL de agua, ¿cuál es la concentración de la disolución?
Answer:
0.020g de sulfato de plomo se requieren
La concentración de la solución diluida es de 3ppm
Explanation:
Las partes por millón (ppm) son definidas como:
miligramos soluto / 1L solución.
Si deseas preparar una solución a 100ppm de sulfato de plomo (II) necesitas 100mg de este sulfato en 1L. En 200mL = 0.200L vas a necesitar:
0.200L × (100mg / 1L) = 20mg de sulfato de plomo (II).
Como 1000mg = 1g,
20mg × (1g / 1000mg) = 0.020g de sulfato de plomo se requieren.
Ahora, se van a tomar 30mL de esta solución y se diluirán a 1000mL. Se diluye la solución:
1000mL / 30mL = 33.33 veces.
Como la solución inicial es de 100ppm, esta dilución genera una solución de concentración:
100ppm / 33.33 = 3ppm
The intake stroke of a positive displacement compressor is most similar to that of a
A. thermostatic expansion valve.
B. auxillary electric water pump.
C. one-stroke variable displacement compressor.
D. two-stroke cylinder engine.
Answer:
D. two-stroke cylinder engine.
Explanation:
Two-stroke cylinder engine: In chemistry, the term "two-stroke cylinder engine" is described as one of the types of "internal combustion engine" that tends to complete a single "power cycle" possessing two different strokes of the "piston" during a particular "crankshaft revolution".
It generally consists of two different strokes that are being often known as power or exhaust and suction stroke.
In the question above, the given statement signifies the "two-stroke cylinder engine".
Balancing Chemical Reactions Worksheet A glow stick is a popular toy and safety device. To use a glow stick, you bend a small flexible plastic tube to break a small glass capsule inside, at which point the stick begins to glow. How do you think this works
Answer:
Concept of chemi-fluorescence
Explanation:
A glow stick usually consists of two chemicals in a larger plastic tube: , a base catalyst (mostly sodium salicylate), and a suitable dye (sensitizer, or fluorophor). This creates an exergonic reaction when mixed together.
When a glow stick is bent, the flurophor which is a chemical that easily re-emits light upon excitation in smaller capsules is released into the other substance, there by causing it to emit radiation/light in the uv-visible region. The brightness and longevity of the glow stick is determined by varying the concentration of these chemicals.
I hope this explanation clarifies things.
How did Bohr describe the arrangement of particles within an atom?
A. Protons and electrons form the nucleus, with neutrons
orbiting it.
O B. Neutrons make up the atom's nucleus, with electrons and
protons orbiting it.
c. Protons make up the atom's nucleus, with electrons and
neutrons orbiting it.
O D. Protons and neutrons form the nucleus of the atom, with
electrons orbiting it.
Bohr describe the arrangement of particles within an atom by: O D. Protons and neutrons form the nucleus of the atom, with electrons orbiting it.
Who is Niels Bohr?This hypothesis states that the atom's core is a small, compact, positively charged nucleus. Protons which have a positive charge and neutrons which are neutral are both found in the nucleus.
Specific energy levels or electron shells are where the negatively charged electrons orbit the nucleus. Due to the quantization of these energy levels, only a limited number of discrete energy states are accessible to electrons.
Therefore the correct option is D.
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Answer the following questions: On a 10-fold dilution of a weak acid, the pH will ______________ . On a 10-fold dilution of a weak base, the pH will ______________. If one adds a very small amount of strong base to a buffered solution, the pH will _______________. Can you make a buffer using a strong acid
Answer:
i) increase
ii) decrease
iii) remain the same
iv) No, because it dissociates completely.
Explanation:
On a 10-fold dilution of a weak acid, the pH will increase because the concentration of hydrogen ions will decrease thereby increasing the pH to close to that of water.
On a 10-fold dilution of a weak base, the pH will decrease due to the removal of hydroxide ions from the solution. This results in the solution having a H closer to that of water.
If one adds a very small amount of strong base to a buffered solution, the pH will remain constant because a buffer solution acts to withstand any change to its pH on the addition of small quantities of either an acid or a base.
A buffer solution cannot be made with a strong acid because thy undergo complete dissociation. Therefore, any small addition of base or acid will result in very large changes in the pH of the solution. A buffer solution is made with a weak acid and its conjugate base or a weak base and its conjugate acid.
To dissolve in water, aluminum (AI) should form a compound with
oxide (O2-).
sulfide (S2-).
nitrate (NO,-).
phosphate (POP).
Answer:
Explanation:
Nitrate of most of the elements are water soluble . Aluminium nitrate is also one of them . Aluminium nitrate is easily dissolved in water . It forms hydrated salt whose formula is as follows
Al( NO₃ )₃ . 9H₂O
It is a white crystalline salt . It is also soluble in alcohol.
In heating and melting curves, what is the name of the heat associated with the solid-liquid phase? A. Heat of formation B. Heat of fusion C. Heat of sublimation D. Heat of vaporization
Answer:
C I believe not quite sure tho
In heating and melting curves, the name of the heat associated with the solid-liquid phase is Heat of fusion.
What is the Heat of fusion ?
The standard fusion enthalpy is the amount of thermal energy required for a single mole of a substance to change states from a solid to a liquid or vice versa is known as the heat of fusion or specific melting heat. The melting point is the temperature at which it takes place, and it is also known as the latent heat of fusion or the enthalpy change of fusion.The temperature of a liquid or solid goes down when thermal energy is taken away. The temperature rises when heat and energy are added. However, additional energy—the heat of fusion—is required at the melting point—the transition point between solid and liquid. The molecules of a substance need to become more organized in order to change from liquid to solid. They require the withdrawal of additional heat in order to maintain their solid state. In the opposite direction, additional heat is required to induce the disorder from the solid crystal to the liquid.The temperature of water as it freezes can be measured to observe the heat of fusion. When you place a closed container of room temperature water in a very cold environment, say 20 °C, the temperature will gradually fall until it is just below the freezing point. After that, the temperature rises and stays the same as the water crystallizes. The temperature will again fall steadily after it has completely frozen.The heat of fusion causes the temperature to stop falling at (or just below) the freezing point. Before the temperature can continue to fall, the energy from the heat of fusion must be removed—the liquid must transform into a solid.
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A platinum resistance thermometer has resistances of 160.0 when placed in a 0°C ice bath and 243.8 when immersed in a crucible containing a melting substance. What is the melting point of this substance? (Hint: First determine the resistance of the platinum resistance thermometer at room temperature, 20°C.)
Answer:
the melting point T = 125.36°C
Explanation:
Given that:
The resistance of a platinum thermometer at 0°C is [tex]R_o[/tex] = 160.0 ohms
The resistance of a platinum thermometer when immersed in a crucible containing a melting substance [tex]R_t[/tex] = 243.8 ohms
The temperature coefficient at room temperature 20°C = ∝ = 0.00392
The objective is to determine the melting point of this substance
To do that ; at 20°C, the resistance of the platinum thermometer can be calculated as follows:
[tex]R_{20} = R_o(1 + \alpha \Delta T)[/tex]
[tex]R_{20} = 160(1 + (0.00392 \times (20-0)^0C))[/tex]
[tex]R_{20} = 160(1 + (0.00392 \times (20))[/tex]
[tex]R_{20} = 160(1 + (0.0784)[/tex]
[tex]R_{20} = 160(1.0784)[/tex]
[tex]R_{20} = 172.544 \ ohms[/tex]
The resistance of the platinum thermometer at t°C , [tex]R_t[/tex] = [tex]R_{20}(1 + \alpha \Delta T)[/tex]
[tex]243.8 = 172.544(1 + 0.00392 \times (T-20)^0C}[/tex]
[tex]\dfrac{243.8}{ 172.544 }= (1 + 0.00392 \times (T-20)^0C}[/tex]
[tex]1.413 = (1 + 0.00392 \times (T-20)^0C}[/tex]
[tex]1.413-1 = 0.00392 \times (T-20)^0C}[/tex]
[tex]0.413 = 0.00392 \times (T-20)^0C}[/tex]
[tex]\dfrac{0.413 }{0.00392} = (T-20)^0C}[/tex]
105.36°C = (T - 20) °C
T = 105.36°C + 20 °C
T = 125.36°C
What is the freezing point of a solution of 1.43 g mgcl2 in 100 g of water? Kf for water is 1.86°c/m for water.
Answer:
Change in T = i x m x kf. Where i is the number of particles the compound dissociates, m is the molality, and kf is the constant specific to water. MM of MgCl2 = 95.21 g/mol
MgCl2 will form three atoms....i = 3......1Mg + 2Cl
kf = 1.86
moles of MgCl2 = 1.43g/95.21 = 0.015
m = moles solute/ kg solvent = 0.015/.1kg = .15m
Change in T = (3)(.15)(1.86) = .838
This is the depression of the freezing point of water, it is negative because the water's new freezing point is its normal freezing point minus the change in T.
0 - .838 = -.838
Explanation:
144g of KCl dissolved in 1000cm3of water at 90oC. Calculate the solubility of KCl at this temperature. (K=39, Cl=35.5, 1dm3=1000cm3).
Answer:
The solubility of KCl is 1.93 mol/dm³
Explanation:
The information given are;
The mass of the potassium chloride, KCl = 144 g
The volume of the water solvent = 1000 cm³ = 1 dm³
The temperature of the solvent = 90 °C
The atomic mass of potassium, K = 39 u
The atomic mass of chlorine, Cl = 35.5 u
The number of moles of potassium in one mole of potassium chloride, KCl = 1 mole
The number of moles of chlorine in one mole of potassium chloride, KCl = 1 mole
The molar mass of the potassium chloride = 39 + 35.5 = 74.5 g/mol
The number of moles, n, of potassium chloride, KCl in 144 g of potassium chloride, KCl is given as follows
n = Mass/(Molar mass) = 144/74.5 = 1.93 moles
1.93 moles will dissolve in 1 dm³
Therefore, the solubility of KCl is 1.93 mol/dm³.
Which of the mechanical waves below has the greatest energy?
Answer:
Blue wave.
Explanation:
The energy of a wave depends on its amplitude. A wave having more amplitude will have greatest energy while a wave having small amplitude will have least energy. The given figure shows four waves that are shown with green, orange, blue and red color. It is very clear from the figure that the amplitude of blue wave is greatest of all the wave.Hence, blue wave will have greatest energy.calculate the mass of sodium sulphate required to prepare its 20%of solution in 100 g ofwater
Answer:
25 g
Explanation:
Mass percent implies the mass of solute dissolved in a solution
Mass percent = mass of solute/mass of solute + mass of solvent × 100/1
Since mass percent concentration= 20%
Mass of solvent = 100g
Let mass of solute = x
Hence;
20 = x/x +100 ×100/1
20/100= x/x + 100
0.2 = x/x + 100
0.2(x + 100) = x
0.2x + 20 = x
20 = x - 0.2x
20 = 0.8x
x= 20/0.8
x= 25 g
Based on the kinetic molecular theory, which of the following statements is correct about the particles in a sample of gas at a constant temperature and
volume?
They have negligible kinetic energy
They attract each other with strong forces.
There is a lot of empty space between them.
Their net kinetic energy decreases due to collisions.
Answer:
There is a lot of empty space between them.
Explanation:
The kinetic molecular theory postulates that a substance is made up of tiny particles called molecules. The molecules of a gas are in constant random motion and collide elastically with each other. They also collide with the walls of the container.
The magnitude of intermolecular forces of attraction between gas molecules is very small. Hence gas molecules are largely apart with a lot of empty space between gas molecules.
Answer:C, There is a lot of empty space between them.
Explanation:
Name a Solid, Liquid, and a Gas. Solid: Liquid: Gas:
Answer:
Gas - Steam
Solid - Rock
Liquid - Juice
Answer:
Solid: Ice
Liquid: Water
Gas: Steam or Water vapor
Explanation:
This is a common example to answer your question. Some other examples are:
-most metals(ex: iron, tin, copper, gold) These are solids
-milk, juice, hot chocalate, any soda drink These are liquids
-hydrogen, helium, carbon dioxide, oxygen These are gases
Hope this helps!
which of the following would be an appropriate situation for you to use the eye wash station
Answer:
if your eyes are exposed to a hazardous chemical you should use the eye wash station. The first few seconds after exposure to a hazardous chemical are critical.
The radioactive isotope used for carbon dating is
1. Carbon 12
2. Carbon 13
3. Carbon 15
4. Carbon 14
Carbon 14 would be your answer, however if it's more than one answer it would also be Carbon 12, so yeah. Your best bet would be Carbon 14.
The Michaelis constant, Km, refers to the __________ at which a reaction proceeds at __________ of the maximum velocity. This constant most accurately reflects __________. The Michaelis constant, Km, refers to the __________ at which a reaction proceeds at __________ of the maximum velocity. This constant most accurately reflects __________. product concentration; one-half; structure of the substrate enzyme concentration; one-half; temperature optimum of the enzyme substrate concentration; one-half; the affinity of the substrate-enzyme interaction substrate concentration; one-fourth; pH optimum of the enzyme
Answer:
substrate concentration; one-half; the affinity of the substrate-enzyme interaction
Explanation:
The Michaelis constant, Km, refers to the substrate concentration at which a reaction proceeds at one-half of the maximum velocity. This constant most accurately reflects the affinity of the substrate-enzyme interaction.
Which of the following will only affect the reaction rate of gases?
A. Concentration
B. Catalyst
C. Pressure
D. Surface area
Answer:
D. Pressure
Explanation:
The rate of a reaction is defined as the speed at which the reactants are converted into products. Factors influencing the rate of a reaction are concentration, catalyst, temperature, surface area, and pressure, etc.
In case of the reaction rate of gases, pressure will only have its affect as pressure do not have any influence on solid and liquid.
While concentration, surface area and catalyst influence all reaction rates including solid, liquids and gases.
Hence, the correct option is (d) pressure.
Which of the following is an aldehyde?
Answer: [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde functional group.
Explanation:
Functional groups are specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.
A. [tex]CH_3CH_2CH_2COCH_3[/tex] has ketone [tex]C=O[/tex] functional group .
B. [tex]CH_3CH_2CH_2COOH[/tex] has carboxylic acid [tex]COOH[/tex] functional group .
C. [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde [tex]H-C=O[/tex] functional group .
D. [tex]CH_3CH_2CH_2COOCH_3[/tex] has ester [tex]RO-C=O[/tex] functional group .
Thus [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde (CHO) group.
Define the term “Tyndall effect”. Which of the following would show Tyndall effect:- (Starch solution, sodium chloride solution, alcohol and water mixture)
Answer:
Tyndall Effect is the phenomenon of scattering of light by particles in a colloid or in a very fine suspension.
Starch solution would show Tyndall effect.
N/B: Heterogeneous mixtures show Tyndall effect.
Answer:The Tyndall effect is light scattering by particles in a colloid or in a very fine suspension. Also known as Willis–Tyndall scattering, it is similar to Rayleigh scattering, in that the intensity of the scattered light is inversely proportional to the fourth power of the wavelength, so blue light is scattered much more strongly than red light. An example in everyday life is the blue colour sometimes seen in the smoke emitted by motorcycles, in particular two-stroke machines where the burnt engine oil provides these particles.
Under the Tyndall effect, the longer wavelengths are more transmitted while the shorter wavelengths are more diffusely reflected via scattering. The Tyndall effect is seen when light-scattering particulate matter is dispersed in an otherwise light-transmitting medium, when the diameter of an individual particle is the range of roughly between 40 and 900 nm, i.e. somewhat below or near the wavelengths of visible light (400–750 nm).
It is particularly applicable to colloidal mixtures and fine suspensions; for example, the Tyndall effect is used in nephelometers to determine the size and density of particles in aerosols and other colloidal matter (see ultramicroscope and turbidimeter).
It is named after the 19th-century physicist John Tyndall.
Explanation:
Eczema is a type of skin disease that appears as rashes or swelling. Eczema causes skin irritation or itchiness. What type of tissue does eczema affect? A. nervous B. muscle C. epithelial D. connective
Answer:
epithelial
Explanation:
nervous tissue are located only on specific areas mainly in the dermis like the parcinian to detect pressure so rashes won't be seen.muscle is located deep under the sub cutaneous layer so the symptoms can't appear.connective is also located deep in the skin eg in the eyes but epithelial tissue covers the deeper latest of the skin therefore this condition's signs can be well acknowledged I guess