Answer:
4 calcium ions and 4 sulfide ions.
Explanation:
In a face centered unit cell, 8 corners of the unit cell are occupied by 8 atoms. Each corner is 1/8 of a cell. In addition it has 6 atoms in the face of the lattice, which is 1/2 of a cell. (1/8 * 8) + (1/2 * 6) = 4. CaS has a 1:1 ratio. Therefore, they each have 4 ions.
Each cubic unit cell contains FOUR (4) calcium ions in octahedral holes and FOUR (4) sulfide ions at the lattice points.
Calcium sulfide is a solid inorganic compound (chemical formula: CaS) that shows a white appearance and crystallizes in cubes like rock salts. This molecule (calcium sulfide) is widely used to produce certain classes of paints, ceramics, paper, etc.Calcium has a valence of 2 electrons, while sulfur has '6' valence electrons, thereby the number of valence electrons in CaS is equal to 2 + 6 = 8.Calcium sulfide (CaS) adopts a sodium chloride crystal structure where each CaS unit cell contains four sulfide (S²⁻) ions and four calcium (Ca²⁻) ions.In conclusion, each cubic unit cell contains FOUR (4) calcium ions in octahedral holes and FOUR (4) sulfide ions at the lattice points.
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Oxygen gas is made of molecules like the one this model shows. Which
chemical formula most likely describes oxygen gas?
A. OG
B. 00
C. 02
D. 0100
Calculate the amount of heat required to raise the temperature of a 32g sample of water from 8°C to 22°C.
Answer:
The amount of heat required to raise the temperature of a 32g sample of water from 8°C to 22°C is 1,874.432 J
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
Sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).
Between heat and temperature there is a direct proportional relationship. The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat and the mass of the body. So, the equation that allows to calculate heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature.
In this case:
c= 4.184 [tex]\frac{J}{g*C}[/tex]m= 32 gΔT= Tfinal - Tinitial= 22°C - 8°C= 14°CReplacing:
Q= 32 g* 4.184 [tex]\frac{J}{g*C}[/tex] *14 °C
Solving:
Q= 1,874.432 J
The amount of heat required to raise the temperature of a 32g sample of water from 8°C to 22°C is 1,874.432 J
what volume of 3.25m naoh would be required to form 1 mole of na3po4
Answer: 0.923 L
Explanation: The reaction between naoh and h3po4 is:
3naoh + h3po4 —> na3po4 + 3h20
this means it requires 3 mols of naoh to make na3po4
given the concentration, 3.25 M, the equation looks like this:
3.0 mol x (1.0L/ 3.25mol) = 0.923 L
A 24.00 g sample contains 14.60 g Cl and 9.400 g B. What is the percent composition (by mass) of boron in this sample?
Answer:
39.2 %
Explanation:
The following data were obtained from the question:
Mass of sample = 24 g
Mass of Cl = 14.6 g
Mass of B = 9.4 g
Percentage composition of boron =?
The percentage composition (by mass) of boron in the sample can be obtained as illustrated below:
Percentage composition of boron = mass of B /mass of sample × 100
Percentage composition of boron = 9.4/24 × 100
Percentage composition of boron = 39.2 %
Therefore, the percentage composition (by mass) of boron in the sample is 39.2 %
The percent composition of boron in this sample is 39.17 %.
The mass of chlorine = 14.60 g
The mass of Boron = 9.400g
Mass of the sample = 24.00 g
The percentage composition of boron can be calculated below:
% composition of Boron = 9.4 / 24 × 100
% composition of Boron = 940 / 24
% composition of Boron = 39.1666666667
% composition of Boron ≈ 39. 17%
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Which will require more heat, increasing the temperature of 1 mol of C8H18(l) by a certain amount or increasing the temperature of 1 mol of H2O(l) by the same amount?
Answer:
Increasing the temperature of 1 mol of C8H18(l) requires more energy
Explanation:
To answer this question, we need to define molar heat capacity that is the amount of heat required to increase in 1K the temperature of 1 mole of substance.
That means the substance with higher molar heat requires more energy to increase its temperature
Molar heat of octane, C8H18 is 255.68J/Kmol
Molar heat of water is 75.38J/Kmol
That means increasing the temperature of 1 mol of C8H18(l) requires more energy
When you apply heat energy to a substance, where does the energy go? Think about the law of conservation of energy.
Answer:
the heat energy is transformed to any kind of energy depending on what it's meant to be transformed to.
remember it cannot be destroyed so it's definitely transformed to some kinda energy
Write balanced reactions for the complete combustion of hydrogen. Express your answer as a chemical equation. Identify all of the phases in your answer.
Answer:
Explanation:
A combustion involves the reaction of a fuel with oxygen (O₂). During the reaction of combustion of hydrogen (H₂), H₂ reacts with O₂ to form water (H₂O). The balanced chemical equation is the following:
2 H₂(g) + O₂(g) → 2 H₂O(g)
According to the chemical equation, 2 moles of H₂O are obtained from the reaction of 2 moles of H₂ with 1 mol of O₂. All reactants and products are in the gaseous phase.
Describe the potential energy of a chemical reaction and how the energy is accessed?
Explanation:
The energy released due to breakage of bond or we can say that protons and electrons go from a structure of higher potential energy to lower potential energy. During this change, potential energy is converted to kinetic energy in form of heat.
Generally chemical potential energy is accessed in form heat, which the difference between the potential energies of reactant and product.
4. One mole of oxygen contains 6.02 x 102 molecules. How many oxygen molecules are in
5.55 moles of oxygen gas?|
Answer:
3.34x10²⁴ molecules of oxygen
Explanation:
1 Mole of particles of any kind of gases or particles are always 6.022x10²³.
1 mole of electrons are 6.022x10²³ electrons
1 mole of any gas are 6.022x10²³ molecules
1 mole of oxygen are 6.022x10²³ molecules. Thus, 5.55 moles are:
3.34x10²⁴ molecules of oxygenWhich of the following best explains what happens as an ice cube melts? A. Thermal energy is transferred from the ice cube to its surroundings. B. Thermal energy is transferred from the surroundings to the ice cube. C. The chemical bonds holding the ice together break, releasing energy. D. The amount of energy in the ice cube must remain the same
Answer:c
Explanation:I needed points do not take this answer for real!!
Sunday
Monday
What
The
Freak
Saturday
A person aims for a target with a wooden bow and arrow. The image shows the path of the
arrow to the target.
bow and arrow
target
Answer:
What’s the answer
Explanation:
I neeeddsdd
After an afternoon party, a small cooler full of ice is dumped onto the hot ground and melts. If the cooler contained 6.60 kg of ice and the temperature of the ground was 42.5 °C, calculate the energy that is required to melt all the ice at 0 °C. The heat of fusion for water is 80.0 cal/g.
Answer:
The quantity of heat required to melt all the ice at 0°C is 2.21 * 10⁶ J
Explanation:
Latent heat of fusion is the heat absorbed by a unit mass of a given solid at its melting point that completely converts the solid to a liquid at the same temperature. Its unit is Joules/kg or Joules/g.
1 calorie = 4.184 Joules
Therefore , 80.0 cal/g = 80.0 cal/g * 4.184 J/cal = 334.72 J/g
1 g = 0.001 kg; Heat of fusion in J/kg = 334.72 J/g * 1g /0.001 kg = 3.35 * 10⁵ J/kg
Quantity of heat, Q = mass * latent heat of fusion of ice
quantity of heat required = 6.60 kg * 3.35 * 10⁵ J/kg
Quantity of heat required = 2.21 * 10⁶ J
Therefore, the quantity of heat required to melt all the ice at 0°C is 2.21 * 10⁶ J
What is the answer? Please
Answer:
Leeunwenhoek
Explanation:
Anton Von Leeunwenhoek was the first scientist to observe live cells and in greater details. He described spirogyra in the mid 15th century.
His contribution to the scientist community opened up the world of micro-organisms. He produced several microscopes to observed the world of micro-organisms that we cannot see with our naked eyes. He also studied plants extensively.If the net force acting on an object is 0 N, the forces are
Since the forces equal to 0, it's balanced because the object isn't moving.
PLEASE HELP ME ANSWER THIS ASAP! !
Answer:
Change in velocity is -4m\s
acceleration is -2m\s^2 cause Change in velocity = final v - initial v
Explanation:
Calculating acceleration involves dividing velocity by time — or in terms of SI units, dividing the meter per second [m/s] by the second [s]. Thus the SI unit of acceleration is the meter per second squared .
-4 m/s and -2 m/s2
:-)
A reaction of 2.00 ml of nitric acid and excess sodium hydroxide was carried out in
an lae calorimeter. It resulted in a change in volume of the ice/water mixture of
0.217 mL in an Ice calorimeter. The enthalpy of neutralization of nitric acid is -56.3
kJ/mol, density of Ice - 0.917 g/mL, density of water at the 0°C -1.00 g/ml, and
the enthalpy of fusion for ice - 333 J/g. Calculate the molarity of nitric acid.
-1.42 x 10-3M
-4.49 M
-7.09 M
-6.07 x 10-3M
-6.33 x 10-3M
Elements in the same period have _____ in common?
-
Answer:
The elements that have the same number of energy levels or the orbitals.
Explanation:
They have he same number -- energy levels
calculate the mass and charge of one mole of electrons
Answer:
I don't know if this is really helpful or not, but an electron weights 0.00000000000000000000000000091 grams.
Explanation:
May I have brainliest please? :)
Which cannot be chemically broken down into simpler substances?
O compound
O element
O solution
O mixture
Answer:
an element.
Explanation:
it is the purest form
Answer:
b
Explanation:
Which of the following are not decomposition reactions?
A. KCIO3 → KCI + O2
B. CaO + H2O + Ca(OH)2
C. 2Mg + O2 + 2Mgo
O D. NaOH + Na2O + H2O
The following are not decomposition reactions :
B. CaO + H2O ⇒ Ca(OH)2
C. 2Mg + O2 ⇒ 2MgO
Further explanationThe decomposition reaction is a chemical reaction shows the decomposition of a compound into its constituent elements or compounds
General formula :
AB⇒A+B
A. KCIO3 → KCI + O2
decomposition reaction
B. CaO + H2O ⇒ Ca(OH)2
synthesis/combination reaction
C. 2Mg + O2 ⇒ 2MgO
synthesis/combination reaction
D. 2NaOH ⇒ Na2O + H2O
decomposition reaction
A 221 mL cup of whole milk contains about 39 mg of cholesterol. Express the cholesterol concentration of the milk in kilograms per cubic meter (kg/m3)
Answer:
0.1765 Kg / m3
Explanation:
Mass of cholesterol = 39mg
Volume = 221mL
The concentration is given as; Mass/ Volume
Concentration = 39 / 221 = 0.1765 mg /mL
The relationship between mg / mL and Kg / m3 is;
1 mg / mL = 1 Kg / m3
This means that;
0.1765 mg /mL = 0.1765 Kg / m3
How many moles of NaCl , if mixed with excess Pb2+ ions in solution, would be needed to form 45.5 g of PbCl2 ?
The number of mole of NaCl needed to react with excess Pb²⁺ to produce 45.5 g of PbCl₂ is 0.328 mole
We'll begin by calculating the number of mole in 45.5 g of PbCl₂. This can be obtained as follow:
Mass of PbCl₂ = 45.5 g
Molar mass of PbCl₂ = 207 + (35.5×2) = 278 g/mol
Mole of PbCl₂ =?Mole = mass / molar mass
Mole of PbCl₂ = 45.5 / 278
Mole of PbCl₂ = 0.164 mole Finally, we shall determine the number of mole of NaCl needed to produce 0.164 mole (i.e 45.5 g) of PbCl₂. This can be obtained as follow:2NaCl + Pb²⁺ —> PbCl₂ + 2Na⁺
From the balanced equation above,
2 moles of NaCl reacted to produce 1 mole of PbCl₂
Therefore,
Xmol of NaCl will react to produce 0.164 mole of PbCl₂ i.e
Xmol of NaCl = 2 × 0.164
Xmol of NaCl = 0.328 mole
Thus, the number of mole of NaCl needed for the reaction is 0.328 mole
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When the following oxidation–reduction reaction in acidic solution is balanced, what is the lowest whole-number coefficient for H+, and on which side of the balanced equation should it appear?
MnO4–(aq) + I–(aq) → Mn2+(aq) + I2(s)
a. 8, reactant side
b. 16, reactant side
c. 2, product side
d. 4, product side
e. 1, reactant side
Answer:
b. 16, reactant side
Explanation:
Let's consider the following redox reaction.
MnO₄⁻(aq) + I⁻(aq) → Mn²⁺(aq) + I₂(s)
We can balance it using the ion-electron method.
Step 1: Identify both half-reactions
Reduction: MnO₄⁻(aq) → Mn²⁺(aq)
Oxidation: I⁻(aq) → I₂(s)
Step 2: Perform the mass balance, adding H⁺(aq) and H₂O(l) where appropriate
MnO₄⁻(aq) + 8 H⁺(aq) → Mn²⁺(aq) + 4 H₂O(l)
2 I⁻(aq) → I₂(s)
Step 3: Perform the charge balance, adding electrons where appropriate
MnO₄⁻(aq) + 8 H⁺(aq) + 5 e⁻ → Mn²⁺(aq) + 4 H₂O(l)
2 I⁻(aq) → I₂(s) + 2 e⁻
Step 4: Multiply both half-reactions by numbers so that the number of electrons gained and lost are equal
2 × (MnO₄⁻(aq) + 8 H⁺(aq) + 5 e⁻ → Mn²⁺(aq) + 4 H₂O(l))
5 × (2 I⁻(aq) → I₂(s) + 2 e⁻)
Step 5: Add both half-reactions and cancel what is repeated on both sides
2 MnO₄⁻(aq) + 16 H⁺(aq) + 10 e⁻ + 10 I⁻(aq) → 2 Mn²⁺(aq) + 8 H₂O(l) + 5 I₂(s) + 10 e⁻
The balanced reaction is:
2 MnO₄⁻(aq) + 16 H⁺(aq) + 10 I⁻(aq) → 2 Mn²⁺(aq) + 8 H₂O(l) + 5 I₂(s)
Toluene is subjected to the action of the following reagents in the order given: (1) KMnO4,OH-, heat; then H3O (2) HNO3, H2SO4 (3) Br2, FeBr3 What is the final product of this sequence?
Answer:
See image attached
Explanation:
The reaction of toluene with alkaline potassium permanganate in the presence of heat leads to the oxidation of the -CH3 to give benzoic acid.
Reaction benzoic acid with HNO3/H2SO4 yields the nitronium ion (NO2+).
Recall that -COOH is a metal director and deactivated the ring towards electrophilic substitution hence the m-nitrobenzoic acid is formed.
Reaction with FeBr3/Br2 yields the product shown in the image attached.
Describe the transfer of thermal energy as the ice cream melts and as it becomes solid again. In both situations, describe which objects are gaining and losing energy.
Answer:
Melting = endothermic, solid = exothermic
Explanation:
Ok so when ice cream melts, that requires heat, so it’s Endothermic. In order to melt it, it requires heat, heat is entering. When it becomes solid again, that is exothermic because it is losing heat in order to become cool again.
Draw the Lewis structure of (CHO)OCH, and then choose the appropriate set of molecular
geometries of the three central atoms. Your answer choice is independent of the orientation of
your drawn structure.
A) pyramidal/pyramidal / trigonal pyramidal
B) planar / trigonal pyramidal/trigonal planar
+
C) bent (120°) /planar/planar
D) trigonal planar / bent (109.5°) /tetrahedral
E) planar / planar / linear
Click to draw a new structure
Answer:
B
Explanation:
it does not have the lone pairs.
The respective molecular geometries of the central atoms in the molecule are; trigonal planar / bent (109.5°) /tetrahedral.
We know that the shape of molecules depends on the number of electron pairs that surround the central atoms in a molecule. In the molecule (CHO)OCH3, there are three central atoms.
From the Lewis structure of the molecule (CHO)OCH3 shown in the image attached, we can clearly see that the respective geometries of the central atoms in the molecule is; trigonal planar / bent (109.5°) /tetrahedral.
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A ball is rolling 0.25 meters per second. How fast is it moving in units of miles per hour?
Answer:
0.56 mi/hr
Explanation:
Pre-Lab Questions
Which of the following are considered matter?
electricity
fire
air
water
Answer:
Fire, Air, Water.
Explanation:
Matter is anything that has mass and occupies space. However, not all form of matter are visible. Air is an example of invisible matter.
Note, electricity does not have mass or does not occupy space. Therefore, electricity is not a matter.
Answer:
Fire, Air, Water
Explanation:
Electricity is the of charged particles conducting medium. However, it is the electrons that are matter, not their movement.
Matter is anything that has mass and occupies space. The flame itself is a mixture of gases and so is matter. The light and heat produced are energy not matter.
Like solids and liquids, air is matter. It has a weight and it takes up space.
Water is a liquid and liquids are one of the four fundamental states of matter.
The chart shows the frequencies of certain colors of visible light. A 2 column table with 4 rows. The first column is labeled light with entries red, violet, green, orange. The second column is labeled frequency in hertz with entries 4.5 times 10 Superscript 14 baseline, 7.5 times 10 Superscript 14 baseline, 6.0 times 10 Superscript 14 baseline, 5.0 times 10 Superscript 14 baseline. Which colors will eject electrons when they strike sodium, which has a frequency threshold of 5.7 × 1014 Hz? violet and green red and orange violet only red, violet, green, and orange
Answer:
Violet only
Explination:
Violet is the only color that will eject electrons when it strikes sodium.
The colors that will eject electrons when there's a strike with sodium from the chart will be A. Violet and green.
ElectronsFrom the complete information, William made a chart in order to illustrate the result of the experiment that was made with the photoelectric effect.
In this case, the colors that will eject electrons when they strike sodium, with the frequency threshold will be violet and green.
This was gotten from the result that the frequencies of light were lower than the frequency threshold.
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