Answer:
[tex]2Na + Ca^{2+} \rightarrow Ca + 2Na^+[/tex]
Explanation:
Hello!
In this case, since this a reaction in which the oxidation state of the metals is changing, we need to apply a redox method for which:
[tex]Na\rightarrow Na^++e^-\\\\Ca^{2+}\rightarrow Ca+2e^-\\\\\\2Na\rightarrow 2Na^++2e^-\\\\Ca^{2+}\rightarrow Ca+2e^-[/tex]
Thus, the result is:
[tex]2Na + Ca^{2+} \rightarrow Ca + 2Na^+[/tex]
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What do atoms make up
Fred is about to order a stack of four pancakes with butter and syrup, but he wonders how much he would need to exercise to burn off the Calories from it. He pulls out his cell phone and finds the nutritional information for the stack of pancakes. He notes that a serving has 181g of carbohydrates, 27g of fat, and 16g of protein. Now, he has to convert these values into Calories.
Running at a pace of 8 minutes per mile burns 14 Calories/minute. How many minutes would he have to run at an 8 minutes per mile pace to bum off the Calories from the stack of pancakes?
Answer:
The correct answer is - 73.64 minutes.
Explanation:
We know that each gram of protein and carbohydrate produces 4 calories of energy whereas fat produces 9 cal energy per gram.
So, the Calories from carbohydrates
= 181 ×4
= 724 Cal
and, 27 g fat produces = 27 × 9 = 243 Cal
and, 16 g protien = 16 × 4 = 64 Cal
so the total energy will be - 243+ 724+ 64 = 1031 Cal
Thus, the time Fred need to run = 1031/14 =73.64 min
Is nitric acid a strong or weak acid. Explain your answer.
Answer:
Examples of strong acids are hydrochloric acid (HCl), perchloric acid (HClO4), nitric acid (HNO3) and sulfuric acid (H2SO4). A weak acid is only partially dissociated, with both the undissociated acid and its dissociation products being present, in solution, in equilibrium with each other.
Explanation:
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२
1. A ratio of the parts of a mixture are exact true or false.
Determine whether each observation generally corresponds to a physical change or a chemical change. A liquid freezes into a solid. _________ Bubbles are produced upon mixing two solutions. __________ A precipitate is formed from two solutions. _________ A solution heats up upon mixing with another. ____________ A solid dissolves into water. __________ The color of a substance changes over time
Answer:
A liquid freezes into a solid or any other state change is a physical change. Bubbles are produced upon mixing two solutions is a Chemical change as gas formed. a precipitate is formed from two solutions is a Chemical change The conversion of a substance to another compound over time leads to a color change of the substance due to the insolubility of the compound.
It is a chemical change or properties. A solution that heats up upon mixing with another is a Chemical change known as an exothermic reaction. dissolving the substance in a liquid is a physical change physical that can be regained by evaporation or crystalization.
The map shows the average high temperatures in July for two cities in Texas.
Average July High Temperatures
Texas
Del Rio
36°C
Galveston
32°C 12
Answer:
Highest temperature which was recorded in Texas was 40 degrees.
Explanation:
Texas has variating weather. In summer Texas city turns to be very hot and during winters the city of Texas experience fall in temperature. There is very few rainfall in Texas due the climatic conditions.
17. Which of the following statement best explains what pollination is?
A. It is the union of sperm and egg cell.
B. It is the process where the pollen of one flower reaches the stigma of another flower.
C. It is the process wherein plants are developed from seeds.
D. It is the process by which seeds are sent by their parent plant into a faraway place to
become a new plant.
Answer:
ıt is the projesi where the polen of one flower reaches the sığmaz of another flower.
Answer:
B
Explanation:
Have a nice day☺gsjsjamsvwksk
This is the chemical formula for Chormium (III) nitrate Cr(NO3)3Calculate the mass percent of nitrogen in chromium(III) nitrate.
Answer:
The percent composition for nitrogen in chromium(III) nitrate is 6%.
Explanation:
The mass percent of nitrogen in chromium(III) nitrate is 17.655%.
Calculation,
Molar mass of one oxygen = 16 g
molar mass of nine oxygen = 9 × 16 g = 144 g
molar mass of one nitrogen atom = 14 g
molar mass of three nitrogen atom = 3 × 14 g = 42 g
molar mass of one chromium atom = 51.99 g
molar mass of chromium (III) nitrate molecule = 144 g + 42 g + 51.99 g = 237.99 g
Mass percent of nitrogen = mass of three nitrogen atom× 100 /mass of chromium(III)nitrate
Mass percent of nitrogen = 42 g/237.99 g × 100 = 17.655%
What is mass percentage?The percentage of the mass of the element or solute divided by the mass of the compound or solute is called mass percentage
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Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that 92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
Answer:
the change in energy of the gas mixture during the reaction is 227Kj
Explanation:
THIS IS THE COMPLETE QUESTION BELOW
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
From thermodynamics
ΔE= q + w
Where w= workdone on the system or by the system
q= heat added or remove
ΔE= change in the internal energy
q=+ 319kJ ( absorbed heat is + ve
w= -92kJ
If we substitute the given values,
ΔE= 319 + (-92)= 227 Kj
With the increase in enthalpy and there is absorbed heat, hence the reaction is an endothermic reaction.
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DIMENSIONAL ANALYSIS CHEMISTRY SUPER easy MOLE CONVERSIONS!!
Question : How many moles of O2 are in the sample of 3.6 kilograms of air if 21% of the air is oxygen O2 by mass?
Answer:
47.25 moles
Explanation:
First we find the amount of O2 in mass in air
That will be = (21/100) x 3.6
This will give us=0.756 kg
Now we want to find the moles, so we convert this mass into grams since we are going to be working with grams= 0.756 x 1000 = 756 grams
Now, to find the number of moles:
moles= mass / molar mass
in this case mass is 756 grams and molar mass of oxygen is 16
So, the mass divided by molar mass would be =756/16= 47.25 moles of O2
2. How many moles are there in 20 grams of Carbon?
Answer:
1.6666666666666 is the ans bcz in each mole there r 12 grams of carbon so the ans is goingtobe 20÷12
According to the mole concept, there are 1.66 moles in 20 grams of carbon.
What is a mole?
Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
Number of moles is calculated as, mass/molar mass, thus on substitution , number of moles=20/12=1.66 moles.
Thus, there are 1.66 moles in 20 grams of carbon.
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If the mercury in a manometer raises 30.0 millimeters due to a change in pressure, what is the corresponding change in pressure in atm?
Answer:
0.03947 atm
Explanation:
The relationship between mmHg and atm is given as;
1 atm = 760 mmHg
x atm = 30 mmHg
Upon solving for x;
x * 760 = 30 * 1
x = 30 / 760 = 0.03947 atm
Jane is sitting in the family car. Her mother is driving her from their house to the library. Jane waves as she passes her friend Marina. Which of the following is not moving with respect to Jane?
A. Marina
B. The family car
C.The library
D. Jane’s house
Answer:
B) The family car
Explanation:
I hope this helps :)
Answering the following questions will help you focus on the outcomes of the experiments.
Experiment 1:
1. What happens to the water in the small tube as the water in the test tube absorbs heat?
2. Why do you think a small tube was used to observe the expansion of water?
Experiment 2:
1. Compare the circumference of the balloon before and after freezing. What is the percent increase in this
measurement?
Combined Results
Write a summary paragraph discussing this experiment and the results. Use the following questions and topics to help
guide the content of your paragraph.
Summarize the conclusions that you can draw from this experiment. Use the questions above to guide your ideas.
2. Summarize any difficulties or problems you had in performing the experiment that might have affected the results.
Describe how you might change the procedure to avoid these problems.
3. Describe at least two real-world issues or examples that illustrate the findings of this experiment.
WRITER
Word Count: of 400
OVERALL SCORE:
Answer:
ex.1
1.The water in the test tube expands as it is heated. There is only one direction to expand in, the glass tube. This glass tube is narrow so that a small change in volume will result in a considerable change in height; your signal is amplified. This is the same phenomenon as in thermometers with a glass bulb on the lower end.
2. there will be a thermal expansion will happened.
Both magnetic fields and electric fields can exert a force true or false?
Answer:
false
Explanation:
An electric field may do work on a charged particle, while a magnetic field does no work.
Each polysaccharide tested gives different color results with the iodine test
A 0.90 g of hydrogen chloride (HCl) is dissolved in water to make 5.0 L of solution. What is the pH of the resulting hydrochloric acid solution?
Express the pH numerically to two decimal places.
0.50g of sodium hydroxide (NaOH) pellets are dissolved in water to make 4.0L of solution. What is the pH of this solution?
Express the pH numerically to two decimal places.
Answer:
Explanation:
Mol weight of HCl = 36.5
.90 g of HCl = .90 / 36.5 mole = .02465 mole
HCl = H⁺ + Cl⁻
1 mole 1 mole
1 mole of HCl gives 1 mole of H⁺
.02465 mole of HCl will give .02465 mole of H⁺
.02465 mole of H⁺ in 5 litre soln
concentration of H⁺ = .02465 / 5 = 4.93 x 10⁻³ M
pH = - log ( 4.93 x 10⁻³ )
= 3 - log 4.93
= 3 - .693
= 2.307
= 2.31
NaOH :
Mol weight of NaOH = 40
.50 g of HCl = .50 / 40 mole = .0125 mole
NaOH = Na⁺ + OH⁻
1 mole 1 mole
1 mole of NaOH gives 1 mole of OH⁻
.0125 mole of NaOH will give .0125 mole of OH⁻
.0125 mole of OH⁻ in 4 litre soln
concentration of OH⁻ = .0125 / 4 = 3.125 x 10⁻³ M
pOH = - log ( 3.125 x 10⁻³ )
= 3 - log 3.125
= 3 - .495
= 2.505
pH = 14 - pOH
= 14 - 2.505
= 11.495 .
= 11.50
Blank is ____ rock in molten form
What is this please help
Answer:
Rock In molten form is Lava
^_^
3. Which state of matter has a defined shape?
HELP FAST
Answer:
Solid state of matter has a definite shapeThe answer to this is solids!
which one of the following are pure substances : water,salt water,copper,brass,air,oxygen
Answer:
Copper, Water, and Oxygen
Explanation:
Because they are compounds and compounds are pure substances <3
Answer: copper
Explanation: because all of the atoms that make up copper are copper i.e its not a compound or mixture. not made od molecules
When drawing a Bohr model for Sulfur, how many energy levels will you
draw?
5
4
3
2.
Answer:
3
Explanation:
2,8,6
Consider two compounds. Compound A contains 15.7 g of sulfur and 18.6 g of fluorine. Compound B contains 25.4 g of sulfur and 60.2 g of fluorine. For Compound A, the ratio of fluorine to sulfur is 1.18. For Compound B, the ratio of fluorine to sulfur is 2.37. Using the Law of Definite Proportions (also called the Law of Constant Composition), could Compound A and Compound B be the same compound
Answer:
No, compound A and B are not the same compound
Explanation:
According to the law of definite proportion "every chemical compound contains fixed and constant proportions (by mass) of its constituent elements." (Encyclopedia Britannica)
We can see in the question that the ratio of flourine to sulphur in compound A is 1.18 while the ratio of flourine to sulphur in compound B is 2.37.
The two chemical compounds do not contain a fixed proportion by mass of their constituent elements therefore, they can not be same compound according to the law of definite proportions.
The molecular-orbital model for Ge shows it to be:_______.
A) a conductor, because all the lower energy band orbitals are filled and the gap between the lower and higher bands is large.
B) an insulator, because all the lower energy band orbitals are filled and the gap between the lower and higher bands is large.
C) a semiconductor, because the gap between the filled lower and empty higher energy bands is relatively small.
D) a semiconductor, because the gap between the filled lower and empty higher energy bands is large.
E) a conductor, because its lower energy band orbitals are only partially filled.
Answer:
Option C
Explanation:
Pure germanium is a bad conductors of electricity. It is so because its valence band is full and its outer electrons are attached through covalent bond is a diamond like framework. In metallic sense, it is neither a conductor nor an insulator but a semiconductor. It has a small band gap of 0.7eV.
Hence, option C is correct
What is the molecular weight of magnesium chloride?
Answer:
Magnesium chloride/Molar mass
95.211 g/mol
Explanation:
Look at sample problem 19.5 in the 8th ed Silberberg book. Write the ion-product expression at equilibrium for each compound: How to enter the correct answer: e.g. silver sulfate (Ag2SO4) enter this: {Ag+}2{SO42-} don't enter spaces, use square brackets [] not{}or () for concentration and don't worry about subscripting or superscripting
(1) magnesium carbonate
(2) calcium phosphate
(3) silver sulfide
Answer:
See explanation
Explanation:
The term ion product is an expression that does not necessarily reflect equilibrium conditions which can be used to determine the concentration of ions in a solution of the stated substance. As a matter of fact, the ion product is different from the solubility product which reflects equilibrium conditions.
The ion product of the following substances are shown below;
magnesium carbonate - MgCO3
MgCO3(aq) -------> [Mg^2+] [CO3^2-]
calcium phosphate - Ca3(PO4)2
Ca3(PO4)2(aq) --------> [Ca^2+]^3 [PO4^3-]^2
silver sulfide - Ag2S
Ag2S(aq) --------> [Ag^+]^2 [S^2-]
I need help answering number 14 A B and C. Thank you!
Answer:
Explanation:
TiO2 + C + 2 CI2 → TiCI4 + CO2
(a)
(2.16 mol TiO2) x (2 mol CI2 / 1 mol TiO2) x ( 70.9064 g C/mol) = 306 g CI2
(b)
(2.16 mol TIO2) x (1 mol C / 1 mol TiO2) x ( 12.01078 g C/mol)n= 25.9 g C
(c)
Use the law of conservation of mass:
(2.16 mol TiO2) x ( 79.8660 g TiO2/mol) + (306 g CI2 + 25.9 g C = 504 g total.
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Plz help it over science stuff
what’s the answer please
Answer:
5 × 10⁻³ mol
Explanation:
Step 1: Given data
Volume of HCl solution (V): 25 cm³Molar concetration of the HCl solution (C): 0.2 mol/dm³Step 2: Convert "V" to dm³
We will use the conversion factor 1 dm³ = 1000 cm³.
25 cm³ × 1 dm³/1000 cm³ = 0.025 dm³
Step 3: Calculate the moles of HCl (n)
We will use the definition of molarity.
C = n/V
n = C × V
n = 0.2 mol/dm³ × 0.025 dm³ = 5 × 10⁻³ mol
If a solution containing 24.0 g of a substance reacts by first-order kinetics, how many grams remain after three half-lives?
Answer:
3.0g remain
Explanation:
The half-life is defined as the time required for a reactant to decrease its concentration in exactly the half of the initial amount of reactant. Having this in mind:
In one half-life, the mass will be:
24.0g / 2 = 12.0g
In two half-lifes:
12.0g / 2 = 6.0g
And in three half-lifes, the mass that remain is:
6.0g / 2 =
3.0g remainA cough syrup has a density of 1.20 g/mL. A doctor orders 48.0 of the syrup for a sick child. How many teaspoons will you administer to the child
Answer:
because I want to save life