Answer:
116 g
Explanation:
From the question given above, the following data were obtained:
Number of mole of calcium = 2.9 moles
Mass of calcium =.?
The mole and mass of a substance are related according to the following formula:
Mole = mass / molar mass
With the above formula, we can obtain the mass of calcium. This can be obtained as follow:
Number of mole of calcium = 2.9 moles
Molar mass of calcium = 40 g/mol
Mass of calcium =.?
Mole = mass / molar mass
2.9 = mass of calcium / 40
Cross multiply
Mass of calcium = 2.9 × 40
Mass of calcium = 116 g
Therefore, the mass of 2.9 moles of calcium is 116 g.
Both the sweatshirt and the balloon are negatively charged. They are most
likely to (blank)
one another.
A-give
B-attract
C-repel
D-help
Answer:
B attract
Explanation:
There will be statication
Which factor has the greatest effect on object X remaining in its orbit?
A:The size of Earth compared to object X
B:The gravitational force between the Earth and object X
C:The gravitational force between the Sun and object X
D: The magnetic field between the Sun and object X.
Explanation:
Stop cheating and use your brains kiddos
The electron affinity of an element is positive if energy is absorbed during the process of accepting an electron and negative if energy is released during the process. Using the electron configuration of the atom or ion undergoing the addition of an electron, predict whether the electron affinity will be positive or negative for the following reactions, and classify them accordingly.
Atom or ion Electron configuration
Ne 1s22s22p6
Br 1s22s22p63s23p64s23d104p5
Na 1s22s22p63s1
Mg 1s22s22p63s2
Cl 1s22s22p63s23p6
Answer:
See explanation
Explanation:
Ne is a noble gas. It already has an octet of electrons hence, the electron affinity of neon is negative.
Br is a halogen, halogens need one electron to complete their octet. The electron affinity for bromine is negative.
Sodium is a metal that has only one electron in its outermost shell. The electron affinity of sodium is positive.
Magnesium is a metal having two electrons in its outermost shell. The electron affinity of magnesium is positive.
Chlorine is another halogen, energy is released when an electron is added to chlorine hence the electron affinity of chlorine is negative.
need this ASAP
Which of these must be FALSE, in order for evolution by natural selection to occur?
A. Variation between individuals exists in a population.
B. Particular variations of traits are passed on from one generation to the next.
C. Resources are limited, leading to competition within the population.
D. The particular traits present in one generation have no effect on traits in the next generation.
thank you :D
which type of neuron carries impulses from the brain?
Answer:
Using my searching skills, the answer is motor neurons.
Explanation:
Motor neurons carry impulses from the brain and spinal cord to muscles or glands.
A student pours 800.0 mL of a 3.000 molar solution of sodium hydroxide into a 2.00 liter volumetric flask and fills the flask up with water. What is the new molarity of the solution?
5 points
12.00 M
1.20 M
14.00 M
0.0750 M
Which of the following safety devices ensures that electricity will flow through it when flowing "downhill" instead of through people? A. Surge protectors B. Electric generators C. Ground wires D. Special plugs for high-current devices
Answer:
Ground Wires
Explanation:
Suggest two observations that would be made when rubidium is added to cold water.
Answer:
1. Rubidium metal reacts very rapidly with water to form a colorless basic solution of rubidium hydroxide (RbOH) and hydrogen gas (H2).
2. Rubidium sinks because it is less dense than water. It reacts violently and immediately, with everything leaving the container. Rubidium hydroxide solution and hydrogen are formed.
What is the total pressure of a mixture of gases, with 23 atm, 10 atm, 16 atm, and 30 atm?
How many levels are in the classification system?
A: 7
B: 2
C: 4
D: 6
Answer:
7
Explanation:
There are seven major levels of classification: Kingdom, Phylum, Class, Order, Family, Genus, and Species.
So, the answer is option A.
Match each object to its definition.
A. meteorite
B. meteoroid
C. meteor
->
1. The remains of a rock from space that strikes Earth’s surface
2. A rock that burns up in Earth’s atmosphere
3. A small piece of rock in space
Answer:
definition 1. goes with B. meteoroid
definition 2. goes with C. meteor
definition 3. goes with A. meteorite
Answer: meteoroid - a small piece of rock in space, meteor - a rock that burns up in Earths atmosphere, meteorite - The remains of a rock from space that strike Earth's surface.
Explanation:
what is the difference between crystalline and amorphous solid..???
Answer:
Crystalline solids have regular ordered arrays of components held together by uniform intermolecular forces, whereas the components of amorphous solids are not arranged in regular arrays.
Explanation:
What is the phase label on H3O+(?)
A. aq
B. s
C. e
D. g
E.
Please help. ASAP!
What most likely happens when water loses heat?
It changes into ice.
It changes into vapor.
Its temperature increases.
Its temperature remains constant.
Answer:
It changes into ice.
Explanation:
solid form of water. When water vapor in the atmosphere cools down, it will condense and change back into liquid water, forming clouds
Answer:
It changes into ice,
Explanation:
Because if it's hot it would melt or evaporate, but if it's LOSING heat it would mean the opposite, and the only one that supports this is that "it changes into ice". Hope this helped, sorry i wasn't on for some time
The molecular weight for this compound is 60.09 g/mol. What is the molecular formula for this compound?
Answer:
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Help plzz pick on the picture
14. Explain, in terms of ions, why a 10.0-milliliter sample of 0.10 M NH4Cl(aq) is a poorer conductor of
electricity than a 10.0-milliliter sample of the 0.30 M NH4Cl(aq).
Neeed now
Which simple machine is best used to split apart an object
A. A screw
B. A lever
C. A wedge
D. A pulley
Answer:
its A screw :))) your welcome
name any
three kinds of mixtures with example
Answer:
Here are a few more examples:
Smoke and fog (Smog)
Dirt and water (Mud)
Sand, water and gravel (Cement)
Water and salt (Sea water)
Potassium nitrate, sulfur, and carbon (Gunpowder)
Oxygen and water (Sea foam)
Petroleum, hydrocarbons, and fuel additives (Gasoline)
Heterogeneous mixtures possess different properties and compositions in various parts i.e. the properties are not uniform throughout the mixture.
Examples of Heterogeneous mixtures – air, oil, and water, etc.
Examples of Homogeneous mixtures – alloys, salt, and water, alcohol in water, etc.
Explanation:
Answer:
smog,mud, cement?
Explanation:
Smoke and fog (Smog)
Dirt and water (Mud)
Sand, water and gravel (Cement)
True or false, rewrite it to make it true.
To balance a chemical equation, only the subscripts of a reactant and product can be changes
Answer:
false
Explanation:
Question 7
3 pt:
N2 + 312 --> 2N13
If 81.3 grams of lodine is reacted with 4.49 grams of nitrogen what is the theoretical yield?
(Include the correct number of significant figures but no units)
Question 8
Answer:
84.3 g of nitrogen triiodide is the theoretical yield.
Explanation:
Hello there!
In this case, according to the chemical reaction:
[tex]N_2 + 3I_2 \rightarrow 2NI_3[/tex]
It is possible to compute the theoretical yield of nitrogen triiodide by each reactant via stoichiometry as shown below:
[tex]m_{NI_3}^{by\ N_2}=4.49gN_2*\frac{1molN_2}{28.01gN_2} *\frac{2molNI_3}{1molN_2}*\frac{394.72gNI_3}{1molNI_3} =126.55gNI_3\\\\m_{NI_3}^{by\ I_2}=81.3gI_2*\frac{1molI_2}{253.81gI_2} *\frac{2molNI_3}{3molI_2}*\frac{394.72gNI_3}{1molNI_3} =84.29gNI_3[/tex]
Therefore, we infer that the smallest amount is the correct theoretical yield as it comes from the limiting reactant, in this case, diatomic iodine as it yields 84.3 g (three significant figures) of nitrogen triiodide as the theoretical yield; incidentally, nitrogen acts as the excess reactant.
Best regards!
Which do all cells need in order to function?
oxygen
water
carbon dioxide
offspring
Answer:
oxygen is the correct answer
Explanation:
you need oxygen in order to breath, eat, drink, and many other stuf! hope i helped!
Compare and contrast the way energy can transfer from one object to another.
Answer:
Energy is transferred from the hotter object to the cooler one, and the difference in temperature between them decreases.Explanation
Consider the Fischer ester synthesis of methyl benzoate from benzoic acid and methanol in the presence of sulfuric acid as a catalyst. A reaction was performed in which 3.8 g of benzoic acid was reacted with excess methanol to make 2.0 g of methyl benzoate. Calculate the theoretical yield and percent yield for this reaction.
Answer:
48.8%
Explanation:
The reaction has a 1:1 mole ratio so;
Number of moles of benzoic acid reacted = mass/molar mass = 3.8 g/122.12 g/mol = 0.03 moles
So;
0.03 moles of methyl benzoate is formed in the reaction
Mass of methyl benzoate formed = 0.03 moles * 136.15 g/mol = 4.1 g
percent yield = actual yield/theoretical yield * 100/1
percent yield = 2.0 g/4.1 g * 100 = 48.8%
A 20.06-mL sample of hydrochloric acid solution requires 25.00 mL of 0.149 M sodium hydroxide for complete neutralization. What is the concentration of the original hydrochloric acid solution?
Answer:
The concentration of the original hydrochloric acid solution is - 0.1856 M
Explanation:
Lets calculate-:
Neutralization reaction follows dilute principle
[tex](N_1)(V_1)=(N_2)(V_2)[/tex] For titration between NaOH and HCl
[tex](M_1)(V_1)_H_C_l=(M_2)(V_2)_N_a_O_H[/tex]
Putting the given values ,
[tex]M_1\times 20.06ml=0.149M\times25.0ml[/tex]
[tex]M_1_H_C_l=\frac{0.149\times25.0}{20.06}[/tex]
= 0.1856 M
Hence , the concentration of hydrochloric acid solution is 0.1856 M.
How many grams of oxygen are needed to burn 10.0 moles of C3H8?
What is the pH of a 0.08 M solution of Ca(OH),?
Answer:
pH = 12.20
Explanation:
Ca(OH)2 is a strong base, so it dissociates completely. A 0.08 M solution of Ca(OH)2 is 0.16 M OH-, since every mole of Ca(OH)2 has 2 OH-.
Calculate pOH using [OH-] = 0.16 M
pOH = -log(0.16) = 0.80
pH = 14 - pOH = 14 - 0.80 = 12.20
Taking into account the definition of pH and pOH, the pH of a 0.08 M solution of Ca(OH)₂ is 13.21
pHFirst of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:
pH= - log [H⁺]= - log [H₃O⁺]
pOHSimilarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
Relationship between pH and pOHThe following relationship can be established between pH and pOH:
pOH + pH= 14
This caseA strong base is one that dissociates completely in water, that is, it contributes the maximum number of OH- ions.
Ca(OH)₂ is a strong base that for each Ca²⁺ cation there are two OH⁻ anions and in which for each mole of Ca(OH)₂ two moles of OH⁻ are formed.
So: [OH⁻]= 2×[Ca(OH)₂]
[OH⁻]= 2×0.08 M
[OH⁻]= 0.16 M
Replacing in the definition of pOH:
pOH= - log (0.16 M)
Solving:
pOH= 0.79
Finally, considering the relationship between pH and pOH:
0.79 + pH= 14
pH= 14 - 0.79
pH= 13.21
In summary, the pH of a 0.08 M solution of Ca(OH)₂ is 13.21
Learn more about pH and pOH:
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Which type of light would make an object appear larger and closer?
Answer:
A convex lens bends light rays inward, which results in the object being perceived as larger or closer.
Explanation:
The light ray refracted from an object may look different based on how they bends light and at what angle. Convex lens bends light inwards and the refracted light appear closer and bigger whereas, a concave lens makes light ray away and smaller.
What is refraction?Refraction is the optical phenomenon by which a light ray bends in its direction when passing from one medium to the other. For instance light ray bends when it pass from air to water or air to glass and vice versa.
The measure of bending of light in a medium is called refractive index of that medium. Refraction makes the object appear to be closer sometimes such as in water when light bends in direction.
When light refracts from convex lens, the bending is inwards and the object is perceived to be closer and larger. Whereas, a concave lens make the bending outwards where the object appeared to be smaller and far.
To find more on refraction, refer here:
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What are similarities and differences between a falling object and a pendulum?
Answer:
The similarity is that they both follow the laws of physics.
In both cases, the motion is opposed by the medium where the object presses through the medium and forces it to part and flow around the object. This creates friction.
If an object is smooth and pointed like a bomb, the friction is minimised. If it is rough with pockets or vertical flat surfaces, the friction is maximised. A parachute presents a round hollow cup face to the flow, maximising friction. This is due to a hole in the top of the parachute.
The difference is the power source. In the vertical direction it is generated by gravity, the force created by the planet. This force is opposed not only by friction but also the difference between the density of the object and the medium surrounding it. If there is a large difference then the acceleration will be large and a high percentage of g.
For example we have a density of 1000 kg/meters cubed and air has a density of 1 Kg per meters cubed, the difference is 999, so we fall at an acceleration of 999/1000 x g. minus the effects of friction.
In the horizontal direction, gravity still opposes the movement creating friction in the vertical direction such as dragging a heavy object on the floor behind you. Force needs to be created horizontally to oppose the friction and to create an acceleration. A balance is soon reached where the acceleration stops and the object is dragged at a constant velocity.
If a small pig runs 46 meters in 6 seconds, what is the pig's average speed?
6 m/s
276 m/s
7 m/s
48 m/s
Answer:
the pig's average speed is 7 m/s
The average speed of a moving body is the ratio of the distance travelled to the time of travel. Here, the speed of the pig running 46 meters in 6 seconds is 7.6 m/s.
What is average speed ?The speed of an object is a physical quantity that measures the distance travelled by the object per unit time. Hence, it is the ratio of distance travelled to the time taken for the travel. The rate of speed is called velocity. Bot are having the standard unit of m/s.
Given that,
distance covered by the pig = 46 meters
time taken = 6 seconds
speed = distance/time.
Average speed of the pig = 46 meters/ 6 seconds = 7.6 m/s.
Therefore, if the small pig runs 46 meters in 6 seconds, it is having an average speed of 7.6 m/s.
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