9. melting point
10. balloons float because they are filled with hydrogen, a gas which is less dense than air.
11. specific gravity
12. element
13. mixture
14. sodium and chlorine
15. cutting of paper
16. condensation
17. 1 and 3
18. heat energy is released
The laboratory test of a patient shows blood calcium level of 8.8meq/l. How many moles of calcium ions are in 0.50l of blood?
Answer:
2.2 × 10⁻³ mol
Explanation:
Step 1: Calculate the number of equivalents in 0.50 L of blood
The blood calcium level of 8.8 meq/L.
0.50 L Blood × 8.8 meq/L = 4.4 meq = 4.4 × 10⁻³ eq
Step 2: Calculate the number of moles of calcium
Calcium has a charge of 2. Thus, it has 2 equivalents per mole.
4.4 × 10⁻³ eq × 1 mol/2 eq = 2.2 × 10⁻³ mol
Select from below all elements that follow the DUET rule (not the octet rule). (you can select multiple)
a) Li
b) Mg
c) O
d)He
e) H
f) Ne
Using the balanced equation below, how many grams of cesium fluoride would be required to make 73.1 g of cesium xenon heptafluoride?
CSF + XeF6 → CsXeF7
Answer:
27.9 g
Explanation:
CsF + XeF₆ → CsXeF₇
First we convert 73.1 g of cesium xenon heptafluoride (CsXeF₇) into moles, using its molar mass:
Molar mass of CsXeF₇ = 397.193 g/mol73.1 g CsXeF₇ ÷ 397.193 g/mol = 0.184 mol CsXeF₇As 1 mol of cesium fluoride (CsF) produces 1 mol of CsXeF₇, in order to produce 0.184 moles of CsXeF₇ we would need 0.184 moles of CsF.
Now we convert 0.184 moles of CsF to moles, using the molar mass of CsF:
Molar mass of CsF = 151.9 g/mol0.184 mol * 151.9 g/mol = 27.9 gWhy are most plants green out of all the colors?
Answer: Different forms of chlorophyll
Explanation:
Depending on the significance the of the chlorophyll it’s function is to absorb light, which excites electrons in the chlorophyll.
Answer:
Plant cells have an organelle called chloroplast in them. Chloroplast contains a green pigment called chlorophyll which gives plants it's green color.
Chlorophyll is important in plants as it helps the plant in producing food with the process of photosynthesis.
How did Rutherford's gold foil experiment show that Thomson's plum pudding model of the atom was
incorrect?
Answer:
He blasted alpha rays at the gold foils. The Alpha rays are charged positive. When he blasted them the protons deflected and changed the course of them and the electrons surrounding the atom let them through. In the plum pudding model they were supposed to be sprinkled on which was clearly wrong according to that experiment.
Explanation:
Aluminum hydroxide, with heat, creates__
Which of the following
Combination,decomposition,
Single replacement,
Double replacement,
Combustion
Answer: Decomposition is the answer
Explanation: why because aluminium hydroxide would decomposes in the presence of heat and would form an oxide which is aluminium oxide and would also form water as a product.
HOPE THIS HELPS!!
Can someone please do 5, 6, 8, 10
Blood tests can be used to check a person's blood glucose and hormone levels. The tabular column given below shows the result of two blood tests carried out on three people to check their blood glucose levels. Person 1 is healthy
Answer:
In after fasting test, Person 2 has slightly higher blood glucose level than person 1.
In after drinking glucose test, Person 3 has much high glucose level than person 1.
Explanation:
Blood sugar test determines the level of glucose present in body. The test can be taken after intake of food / glucose or after fasting for 12 hours. Results of both tests are compared to identify level of glucose present in human body. In after fasting test person has higher glucose and in another test person 3 has higher glucose level.
use a periodic table to write the electron configuration of selenium
Answer: The electronic configuration of selenium is [tex]1s^22s^22p^63s^23p^64s^23d^{10}4p^4[/tex]
Explanation:
The atomic number is defined as the number of protons or number of electrons present in a neutral atom.
Number of electrons will be equal to the atomic number of an atom.
Electronic configuration is defined as the representation of electrons in an atom.
Selenium is the 34th element of the periodic table.
The electronic configuration of Selenium is [tex]1s^22s^22p^63s^23p^64s^23d^{10}4p^4[/tex]
It has 6 electrons that are present in the outermost shell.
CH4 (g) + O2 (g) → CO2 (g) + H2O (g) to. If 28.6 g of CH4 is reacted with 57.6 g of O2, calculate the number of grams of CO2 produced. b. If you actually get 32.1 g of CO2, calculate the percent yield. c. Calculate the number of moles of excess reagent remaining at the end of the reaction.
Answer:
See explanation
Explanation:
First we must obtain the limiting reactant. The equation of the reaction is;
CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g)
Number of moles of CH4= 28.6 g/16g/mol = 1.8 moles
Since the reaction is 1:1, 1.8 moles of CO2 was produced
Number of moles of O2 = 57.6 g/32 g/mol = 1.8 moles
2 moles of O2 produced 1 mole of CO2
1.8 moles of O2 produced 1.8 × 1/2 = 0.9 moles of CO2
Hence O2 is the limiting reactant
Mass of CO2 produced = 0.9 moles × 44 g/mol = 39.6 g
%yield = 32.1g/39.6 g × 100
%yield = 81.1%
According to the reaction equation;
2moles of O2 reacts with 1 mole of CH4
1.8 moles of O2 reacts with 1.8 × 1/2 =0.9 moles of CH4
Number of moles of CH4 left = 1.8 moles - 0.9 moles
Number of moles of CH4 left = 0.9 moles
Which general equation shows a double-displacement reaction?
O A. AB + CD + AC + BD
O B. AB → A+B
O C. AB + CD → AD + CB
O D. A+B → AB
Answer:
O A. AB + CD + AC + BD
explanation:
Explanation:
A.ab+cd+ac+bd is your answer
True or false The atomic number of an element is always more than the mass number of that element.
A gas has a pressure of 450 mmHg at 100 degrees Celsius. What will its new pressure be when the temperature rises 200 degrees Celsius
Answer:
P2 = 900 mmHg.
Explanation:
Given the following data;
Initial pressure = 450 mmHg
Initial temperature = 100°C
Final temperature = 200°C
To find the final pressure, we would use Gay Lussac's law;
Gay Lussac states that when the volume of an ideal gas is kept constant, the pressure of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Gay Lussac's law is given by;
[tex] PT = K[/tex]
[tex] \frac{P1}{T1} = \frac{P2}{T2}[/tex]
Making P2 as the subject formula, we have;
[tex] P_{2}= \frac{P1}{T1} * T_{2}[/tex]
[tex] P_{2}= \frac{450}{100} * 200 [/tex]
[tex] P_{2}= 4.5 * 200 [/tex]
Final pressure, P2 = 900 mmHg.
If a reaction occurs, what will be the products of the unbalanced reaction below?
Cu(s) + Ni(NO3)2(aq)
The Activity Series of Elements
A.
CuNi(NO3)4(s)
B.
Ni(s) + Cu(NO3)2(aq)
C.
No reaction will occur.
D.
CuNi(s) + NO2(g)
Cu(s) + Ni(NO3)2(aq) ⇒Ni(s) + Cu(NO3)2(aq)
The answer is option B.
What is electrochemical series?
Electrochemical or hobby series when the electrodes (metals and non-metals) in touch with their ions are organized on the idea of the values of their preferred discount potentials or standard oxidation potentials, the resulting series is called the electrochemical.
The electrochemical series is built up by means of arranging various redox equilibria so as of their fashionable electrode potentials (redox potentials). The maximum poor E° values are placed at the pinnacle of the electrochemical series, and the maximum wonderful at the lowest.
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14. Which of the following alkanols on oxidation is most likely to yield the
compound below?
CHICHICOOON
.CO
(A) Butanol (B) Propan-2-ol(2-methylbutan-1-ol (D) 2-methylpropan-1-
ol (E) 2-methylpropan-2-ol.
Answer:
A
Explanation:
I think that is the ans but am not sure
Answer:
2-methylpropan-1-ol.
Explanation:
[tex]{ \tt{CH _{3}CH(CH _{3})CH _{2}OH}}[/tex]
I am doing a lab and I am not sure how to calculate the concentration of the chemical formulas used in the lab. Would I need to use the 15ml and add it to the 10 ml of the first solution to find the concentration. Thank you
Answer:
C = m/V
Explanation:
In order to calculate the concentration of a mixture you would need to use the formula for concentration, which is the following...
C = m/V
In this formula C is the concentration, m is the mass of the compound that is being added and mixed into the solution, and V is the total volume of the mixture. The mass of m is in terms of number of moles. Therefore, we would need more information in order to calculate the actual concentration of the mixture that you are trying to find in this scenario. Using the formula above should be enough using the values that you have in your actual workbook.
The first excited state of a particular atom in a gas is 6.1 eV above the ground state. A moving electron collides with one of these atoms, and excites the atom to its first excited state. Immediately after the collision the kinetic energy of the electron is 3.2 eV. What was the kinetic energy of the electron just before the collision
Answer:
The kinetic energy of the electron just before the collision is 9.3 eV.
Explanation:
We can find the kinetic energy of the electron before the collision can be found by energy conservation:
[tex] E_{i} = E_{f} [/tex]
[tex] K_{a_{i}} + K_{e_{i}} = K_{a_{f}} + K_{e_{f}} [/tex] (1)
Where:
[tex]K_{a_{i}}[/tex]: is the initial kinetic energy of the atom
[tex]K_{a_{f}}[/tex]: is the final kinetic energy of the atom = 6.1 eV + [tex]K_{a_{i}}[/tex]
[tex]K_{e_{i}}[/tex]: is the initial kinetic energy of the electron =?
[tex]K_{e_{f}}[/tex]: is the final kinetic energy of the electron = 3.2 eV
By solving equation (1) for [tex]K_{e_{i}}[/tex] we have:
[tex]K_{a_{i}} + K_{e_{i}} = (6.1 eV + K_{a_{i}}) + 3.2 eV[/tex]
[tex] K_{e_{i}} = 6.1 eV + 3.2 eV = 9.3 eV [/tex]
Therefore, the kinetic energy of the electron just before the collision is 9.3 eV.
I hope it helps you!
How is the relation between the volume and temperature? Explain.
Which of the following statements regarding diffusion is false? Group of answer choices Diffusion is a result of the thermal energy of atoms and molecules. Diffusion occurs even after equilibrium is reached and no net change is apparent. Diffusion requires no input of energy into the system. Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated.
Answer: The statement diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated, is false.
Explanation:
When particles or atoms of a substance are able to move rapidly from one place to another then it is called diffusion.
During diffusion, particles tend to move apart from each other.
For example, spreading of dye molecules into water.
Thus, we can conclude that the statement diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated, is false.
What are the steps for writing the formula for an ionic compound? Naming an ionic compound?
Answer:
i hope it will help you
Explanation:
To find the formula of an ionic compound, first identify the cation and write down its symbol and charge. Then, identify the anion and write down its symbol and charge. Finally, combine the two ions to form an electrically neutral compound.
what is displacement?
Answer:
the moving of something form it's places or position
What are two factors that determine the concentration of hydronium (or hydroxide) ions in an acid (or base) solution?
Answer:
hydronium and hydroxide ions are present both in pure water and in all aqueous solutions, and their concentrations are inversely proportional as determined by the ion product of water (Kw). The concentrations of these ions in a solution are often critical determinants of the solution’s properties and the chemical behaviors of its other solutes, and specific vocabulary has been developed to describe these concentrations in relative terms. A solution is neutral if it contains equal concentrations of hydronium and hydroxide ions; acidic if it contains a greater concentration of hydronium ions than hydroxide ions; and basic if it contains a lesser concentration of hydronium ions than hydroxide ions.
Answer:
hydronium and hydroxide ions are present both in pure water and in all aqueous solutions, and their concentrations are inversely proportional as determined by the ion product of water
Explanation:
Not my work! I hope this helps!
Which of these is an example of a chemical change?
Answer:
D. Burning a peice of wood
Explanation:
Because when you burn wood a chemical reaction happenes between the flames and the wood making the wood into ashes.
Hope this helps you :)
The dissolving salt in water is an an example of a chemical change. The correct option is A.
A chemical change, also known as a chemical reaction, is the production of new substances with changing chemical compositions and characteristics.
In water, sodium chloride dissociates into Na+ ions and Cl- ions, which may be described as a chemical process.
The ionic connections between the atoms are broken as salt dissolves. Because the reactant (sodium chloride or NaCl) varies from the products (sodium and chloride ions), a chemical reaction takes place.
Thus, the correct option is A.
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What is one characteristic that makes Earth capable of supporting life?
A. It has ocean currents that circulate water from pole to pole.
O B. It has a strong magnetic field that protects organisms from
harmful radiation.
C. It is in a solar system located in one of the outer arms of a spiral
galaxy
D. It has more mass than any of the other planets of the inner solar
system.
Answer:
it is option (d)
it has more mass than any of the other planets of the inner solar system
need help really quickly!!
so how do you predict products when only reactants are given?
i can do everything else that’s asked for the hw but i don’t know how to do this one.
the first pair of reactants is calcium hydroxide + ammonium chloride.
Answer: so in this question are reactants are calcium hydroxide and ammonium chloride
Explanation: first of all know that a salt would be formed so here the salts present are calcium and chloride so they would react to form the salt calcium chloride, then since ammonium ions are present ammonia gas would be formed then, hydroxide ions (OH) are also present so water would be formed so our final products would be calcium chloride , ammonia and water .
WORD EQUATION
calcium hydroxide+ ammonium chloride⇒ calcium chloride+ ammonia+ water
CHEMICAL EQUATION
CA(OH)2+2NH4CL⇒ CACL2+2NH3+2H2O
 Help ASAP only right answers only no spam don’t answer if you don’t know
…..
Answer:
Inference
Explanation:
I mean, it's not difficult.
A theory is an unproven explanation.
An inference is a guess/educated guess where you don't have all the facts.
For example, if "Bob" is caught in the kitchen with a ketchup stain on his shirt, you are inferencing that he used the ketchup.
However, if you see a ketchup bottle nearby or saw it earlier, then it is not, because you already have the facts that ketchup was used.
give me a fully balanced equation of lead monoxide and nitric acid
Answer:
Explanation:
Lead Monoxide: PbO
Nitric Acid: HNO3
PbO + 2 HNO3 ---> Pb(NO3)2 + H2O
Answer:
Explanation:
mono mean single so lead monoxide is PbO
nitric acid is HNO3
both Pb n O are double-charged while H n NO3 are single
so balanced eqn is:
PbO + 2HNO3 -> Pb(NO3)2 + H2O
Methane is the main component of natural gas. Using the given reaction enthalpy, calculate the heat energy produced by the combustion of one kilogram of methane.
Answer: The heat energy produced is 53831.25KJ
Explanation:
METHANE is the main component of natural gas. It can undergo combustion reaction in air with a bright blue flame to produce carbondioxide and water. The heat of reaction (enthalpy) is negative because heat is absorbed during the chemical reaction. To calculate the heat energy produced by the combustion of one kilogram (1 kg) of methane the following steps are taken:
Molecular mass of methane =16 gm/mol.
So moles of 1 kg methane =
Given mass of methane ÷ molecular weight of methane
But the given mass = 1kg = 1000g
Therefore,
moles of 1000g methane = 1000÷16
= 62.5 moles
Hence, energy evolved = (moles of methane) × (heat of combustion)
Therefore,
heat energy produced= 62.5 × (-861.3kj)
= -53831.25kj
The heat energy produced by the combustion of one kilogram of methane is –53831.25 KJ
We'll begin by calculating the number of mole in 1 Kg of CH₄
Mass of CH₄ = 1 kg = 1000 g
Molar mass of CH₄ = 12 + (4×1) = 16 g/mol
Mole of CH₄ =?Mole = mass /molar mass
Mole of CH₄ = 1000 / 16
Mole = 62.5 moles Finally, we shall determine the heat energy produced from the reaction.CH₄ + 2O₂ —> CO₂ + 2H₂O ΔH = –861.3 KJ
From the balanced equation above,
1 mole of CH₄ reacted to produce –861.3 KJ.
Therefore,
62.5 moles of CH₄ will react to produce = 62.5 × –861.3 = –53831.25 KJ
Thus, –53831.25 KJ of heat energy is produced.
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What two elements were named after the United States?
please provide is matter about us pure all NCERT questions and answers
Answer:
I hope that's what u were lookong for :))
Explanation: