Answer:
7 significant numbers
Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s) + H2O (l) → Ca(OH)2 (s) In a particular experiment, a 2.00-g sample of CaO is reacted with excess water and 2.14 g of Ca(OH)2 is recovered. What is the percent yield in this experiment? a. 107 b. 1.07 c. 2.88 d. 81.1 e. 93.3
Answer:
The option closest to the percentage yield is option;
d. 81.1
Explanation:
The given chemical equation of the reaction is presented as follows;
CaO (s) + H₂O (l) → Ca(OH)₂
The mass of CaO in the experiment, m = 2.00 g
The volume of water with which the CaO was reacted = Excess volume of water
Number of moles = Mass/(Molar mass)
The mass of Ca(OH)₂ recovered, actual yield = 2.14 g
The molar mass of CaO = 56.0774 g/mol
The number of moles of CaO in the reaction, n₁ = 2.00 g/(56.0774 g/mol ≈ 0.036 moles
The molar mass of Ca(OH)₂ = 74.093 g/mol
The number of moles of Ca(OH)₂ in the reaction, n₂ = 2.14 g/(74.093 g/mol) ≈ 0.029 moles
From the given chemical reaction, one mole of CaO reacts with one mole of H₂O to produce one mole of Ca(OH)₂
Therefore, 0.036 moles of CaO will produce 0.036 moles of Ca(OH)₂
Mass = Number of moles × Molar mass
The mass of 0.036 moles of Ca(OH)₂ ≈ 0.036 moles × 74.093 g/mol = 2.667348 grams
∴ The theoretical yield of Ca(OH)₂ = 2.667348 grams
[tex]Percentage \ yield = \dfrac{Actual \ yield}{Theoretical \ yield} \times 100 \%[/tex]
The percentage yield = (2.14 g)/(2.667348 grams) × 100 = 80.23%
Therefore, the option which is closest is option d. 81.1.
Which of the following statements is true? A. Isotopes of the same element have the same number of protons and neutrons. B. Isotopes have the same physical properties as the normal atom but different chemical properties. C. Isotopes have the same chemical properties as the normal atom but different physical properties. D. If an isotope of one element has the same atomic mass as another element, they will have the same properties.
Answer:
B
Explanation:
Isotopes have the same number of protons but different number of neutrons.
The true statement is,
Isotopes have the same chemical properties as the normal atom but different physical properties.So, option C is correct one.
What is isotopes?The elements have same number of proton but different number of neutrons.Example: hydrogen, deuterium, tritiumWhy isotopes of same elements have different physical properties?The isotopes have different physical properties like freezing point , mass, melting or boiling point etc because they have different mass number .
learn about isotopes,
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how to unscramble dtneinreigs
Answer:
Ingredients OR tenderising
Explanation:
what is mean by stakeholder
Answer:
a stakeholder is a party that has an interest in a company and can either effect or be affected by the business. the primary stakeholder in a typical corporation are its investors , employees, customers and supplies.Answer it answer it answer it
Answer:
[tex]\Large \boxed{\mathrm{A}}[/tex]
Explanation:
Rust formed from iron and oxygen combining is a chemical change, because in a chemical change, the resulting substance(s) will have different properties from the substance(s) before the chemical change.
I cant comment... So is it Right?
3.87 moles of iron bromide yielded10.4 moles of sodium bromide
Answer: 89.57 %
Hope it helps
How many gram of zinc will have to be treated with dilute hydrochloric acid to liberate 1.85 dm³ of hydrogen at 27°C and 750mmHg?
Answer:
Explanation:
given
volume=1.85 d m^3
T=27 degree C=27+273 k=300 k
P=750 mmHg
mass of zinc=?
we know that PV=nRT
n=m/M
PV=mRT/M
M for zinc=65.4
PVM=mRT
m=PVM/RT
m=750*1.85*65.4/0.0821*300
m=90742.5/24.63
m=3684
hope this will help u
what oxide other than NO2 produce two acids when added to water?
Answer:
NO3 will produce 2 acids
using chemical equations, show the different stages of fermentation
please I need help urgently!!!
Answer:
in the fermentati0n process glucose [C6H12O6]c of food is converted into ethanol [ethyl alchol, C2H5OH] and Co2 by yeast cell .In this process yeast cell produce in vertase and zymase enzyme which convert glucose into alcohol .
i.e. c6H12O6========> C2H5OH+Co2+energy
In ∆ABC, if sin A = and tan A = , then what is cos A?
Complete Question:
In ∆ABC, if sin A = 4/5 and tan A = 4/3, then what is cos A?
Answer:
[tex]cos A= \frac{3}{5}[/tex]
Explanation:
Given
[tex]sin A = 4/5[/tex]
[tex]tan A = 4/3[/tex]
Required
[tex]cos A[/tex]
In trigonometry;
[tex]tanA = \frac{sinA}{cosA}[/tex]
Multiply both sides by cosA
[tex]cos A * tanA = \frac{sinA}{cosA} * cos A[/tex]
[tex]cos A * tanA = sinA[/tex]
Divide both sides by tanA
[tex]\frac{cos A * tanA}{tanA} = \frac{sinA}{tanA}[/tex]
[tex]cos A= \frac{sinA}{tanA}[/tex]
Substitute values for sinA and tanA
[tex]cos A= \frac{4/5}{4/3}[/tex]
[tex]cos A= \frac{4}{5} / \frac{4}{3}[/tex]
[tex]cos A= \frac{4}{5} * \frac{3}{4}[/tex]
[tex]cos A= \frac{4 * 3}{5 * 4}[/tex]
[tex]cos A= \frac{3}{5}[/tex]
Shalom, Guys!
The molar mass of strontium (\ce{Sr}SrS, r) is \pu{87.62 g/mol}87.62 g/mol87, point, 62, space, g, slash, m, o, l. Calculate the number of atoms in a \pu{67.5 mg}67.5 mg67, point, 5, space, m, g sample of \ce{Sr}SrS, r. Write your answer in scientific notation using three significant figures. \text{atoms Sr} ______________ atoms Sr
Love, Piper Rockelle
Answer:
4.30 × 10²⁰ atoms
Explanation:
You need to find out how many moles you have. First, convert milligrams to grams.
62.5 mg × (1 g)/(1000 mg) = 0.0625 g
Next, use the molar mass to convert from grams to moles.
0.0625 g ÷ 87.62 g/mol = 7.13 × 10⁻⁴ mol
To convert from moles to atoms, you need to use Avogadro's number (6.022 × 10²³). Avogadro's number is the number of atoms in a mole.
7.13 × 10⁻⁴ mol × 6.022 × 10²³ atoms/mol = 4.296 × 10²⁰ ≈ 4.30 × 10²⁰ atoms
You will have 4.30 × 10²⁰ atoms of strontium.
The number of Strontium atoms are 4.30 × 10²⁰ atoms
Given:
Mass of Strontium = 62.5 mg × (1 g)/(1000 mg) = 0.0625 g
Molar mass of Strontium = 87.62 g/mol
To find:
Moles of Strontium = ?
Number of moles:It is defined as given mass over molar mass.
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}\\\\\text{Number of moles}=\frac{0.0625 g}{87.62 g/mol }\\\\\text{Number of moles}=7.13 * 10^{-4} mol[/tex]
Avogadro's number is the number of atoms in a mole (6.022 * 10²³)
Conversion of moles into atoms:
[tex]7.13 × 10^{-4} mol * 6.022 * 10^{23} atoms/mol \\\\\text{ Sr atoms}= 4.296 * 10^{20} = 4.30 * 10^{20} atoms[/tex]
Thus, Strontium atoms will be 4.30 × 10²⁰ atoms.
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what is the molarity of a 50.0 ml aqueous solution containing 10.0 grams of acetic acid, ch3cooh?
Answer:
3.34 M or 3.34 mol/L
Explanation:
The formula for molarity is moles of solution ÷ liters of solution. So, we have to convert grams into moles and mL to L.
To convert grams to moles, first find the molar mass of CH₃COOH by looking at the atomic mass of each individual element.
C - 2(12.01) = 24.02
H - 4(1.01) = 4.04
O - 2(16.00) = 32.00
= 60.06
Now divide the number of grams by the molar mass.
10.0 g CH₃COOH ÷ 60.06 g = 0.167 mol CH₃COOH
To convert milliliters to liters, divide by 1000.
50.0 mL ÷ 1000 = 0.05 L
Now we can calculate the molarity.
M = moles of solution ÷ liters of solution
= 0.167 mol ÷ 0.05 L
= 3.34 M or 3.34 mol/L
The molarity is 3.34 M.
Hope that helps.
does the tendency to gain electrons decrease as we go down grp 17?
Explanation:
Hi, there!!!!
Let me simply clear you..
Yes,The tendency to gain electrons (in nonmetal) decreases when we go down group 17.
The reason for above answer is when we go downwards in periodic table then the atomic size increases with the addition of number of shells and force of attraction between the nucleus and valance shell decreases. The force of attraction between the nucleus and valance shell becomes weaker due to which the force of attracting the electrons gets decreased.
So, we can say that the tendency to gain electrons decreases as we go down in periodic table.
Hope it helps....
What is known about a reaction with a positive enthalpy?
Answer:
"Endothermic reaction: In an endothermic reaction, the products are higher in energy than the reactants. Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings of the reaction."
Explanation:
When enthalpy is positive and delta H is greater than zero, this means that a system absorbed heat. This is called an endothermic reaction. When enthalpy is negative and delta H is less than zero, this means that a system released heat. This is called an exothermic reaction.
What does a high positive enthalpy mean?
The sign of q for an endothermic process is positive because the system is gaining heat. A chemical reaction or physical change is exothermic if heat is released by the system into the surroundings. Because the surroundings are gaining heat from the system, the temperature of the surroundings increases.
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What is atom economy? A. All of these B. The system that determines how much 1 mole of a pure element costs. C. The measure of how much of the reactants end up as products in a chemical reaction. D. The system of exchanging electrons that occurs in atoms.
Answer:
C
Explanation:
It's the amount of products you get compared to all the reactants you use. It's kind of like economy in that it's profit, and the higher the atom economy the more products/profit you have.
Answer:
C.) The measure of how much of the reactants end up as products in a chemical reaction.
Explanation:
I got it right on founders edtell.
You need 100.00 mL of H20 and 5.00 mL of
liquid plant food to make a solution for your
plants. You forgot to bring a measuring cup
out to the greenhouse, but you do have a scale
and know that the density of H2O is 1.00
g/cm", the density of liquid plant food is 1.21
g/cm' and 1 cm° = 1 mL. How much of the
liquid plant food would you use?
Answer:
6.05 g
Explanation:
Use the density to convert the volume to a weight.
(5.00 mL) × (1.21 g/mL) = 6.05 g liquid plant food
You will need 6.05 g liquid plant food.
How do experiments help scientists learn about the world?
A. Experiments explain scientific theories.
B. Experiments prove the scientists' hypotheses.
C. Experiments test the scientists' ideas.
D. Experiments correct old ideas.
Answer:
C. Experiments test the scientists' ideas.
Explanation:
Experiments test the scientists' ideas. Therefore, the correct option is C.
By testing ideas and hypotheses, experiments are an essential part of the scientific method and aid scientists' understanding of the world. Science uses regulated procedures to detect particular phenomena, track results, and collect data. These studies give researchers a chance to investigate cause-and-effect relationships, detect patterns, and draw conclusions based on the data. Scientists can test their ideas, theories, and predictions by systematically adjusting various factors to see whether experimental results confirm or disprove them.
Therefore, the correct option is C.
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A 50.51 g sample of a compound made from phosphorus and chlorine is decomposed. Analysis of
the products showed that 11.39 g of phosphorus atoms were produced. What is the empirical formula
of the compound?
Answer:
pcl3 is the empirical formula of the compound
Answer in the correct significant figures: 31.2 x 4.13*
Answer:
1.29* 10^2
Explanation:
multiply them and then round
A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
THIS IS THE COMPLETE QUESTION BELOW
46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
Substance Density (g/cm3) Melting Point (°C) Boiling Point (°C)
molybdenum 10.28 2,623 4,639
mercury 13.53 -39 357
hafnium 13.31 2,233 4,603
lead 11.34 327 1,749
A.
molybdenum
B.
mercury
C.
hafnium
D.
lead
Answer :
The correct option is OPTION C.
(C) Hafnium
Explanation;:
We were given the mass of substance as (m) = 46.9 g
The Volume of substance as (V) = 3.5 Cm^3
But we know Density of substance.= Mass/it's Volume
Then Density=46.9/3.5
=13.4g/Cm^3
From the questionthe given substance is solid at room temperature, and let us take Mercury as an example , Mercury is liquid at room temperature. ThenMercury cannot be the answer.
Base on the determined density which is 13.4 and the density of Hafnium also is 13.31 g/cm3 and it is solid at room temperature. Therefore, Hafnium is the only likely element here.
What is the concentration in moles per litre of:
a a sodium carbonate solution containing 53 g of the salt
(Na2CO3) in 1 litre?
b a copper(ll) sulfate solution containing 62.5 g of the salt
(CuSO4.5H20) in 1 litre?
Answer:
the concentration in moles per litre of is
Explanation:
Molarity
mark me as a a brainlist answer
How much energy has your body used, in joules, if your health
device indicates that 450 Calories were burned during your workout? How many
Calories are in a dinner containing 3.5 x 100 joules
Answer:
1,882.8 joules83.652 caloriesExplanation:
Given:
Amount in calories = 450 calories
Amount in joules = 3.5 × 100 joules
Find:
Change in joulesChange in caloriesComputation:
We know that,
1 calories = 4.184 joules
So,
Amount in calories = 450 calories
= 450 × 4.184
= 1,882.8 joules
Amount in joules = 3.5 × 100 joules
= [3.5 × 100] / 4.184
= 83.652 calories
Which of the following would be most likely to form a +2 cation?
The Periodic Table
A. Sulfur (S)
B. Calcium (Ca)
C. Chlorine (CI)
O D. Potassium (K)
Calcium because group 2 metals are all 2+ cations
16. I don't want to go anywhere apart from
Nairobi.
A. instead
B. only
C. besides
D. than
[tex]\huge\red{AnsweR:}[/tex]
I don't want to go anywhere apart from than Nairobi.
[tex]<font color=orange>[/tex]
A. instead
B. only
C. besides
D. than_______________________
#Be Brainly
Identify each of the highlighted materials as an element, a compound, or a mixture, and explain your reasoning.
Answer:
These are compounds.
Explanation:
As it is formed by chemically bonding of two elements C ( carbon) and H (hydrogen) .
Its not a mixture because mixture is Just dispersed of diferrent elements or a compound which are not in fix ratioAnswer:
Butane and benzene are both compounds. They contain multiple elements bonded together in a specific ratio. Kerosene and gasoline are mixtures because they are combinations of several compounds. Oxygen is an element because it is made up of only one type of atom.
Explanation:
Why is graphite slippery when pressed? Select one: a. covalent bonds break b. hexagonal layers slide c. molecules of graphite slide
Answer:
hexagonal layers slide
Explanation:
The layers in graphite can slide over each other because the forces between them are weak. The delocalised electrons are free to move through the structure, so graphite can conduct electricity.This makes graphite slippery, so it is useful as a lubricant .
i think it's right
hope it helps :)
1. what is hard water.
2. Mention four sources of water.
3. write down the chemical formula of water.
4. What is purification of water.
5. Mention two importance of purification of water.
6. Mention 4 method used ot purify water. 7. Mention 4 impurities found in water.
8. Explain the term contaminated of water.
9. State two physical properties of water. 10. mention the names of of the elements that causes hardness in water.
Explanation:
Hard water is a type of water that can not easily lather with soap. Springs, wells, pipe-borneH20. The 2 is in basePurification of water is the cleansing of water to avoid diseases, germs, bacteria. To prevent diseases, to make the water safe for drinkingBoiling,chlorination, distillationSorry about number seven! This is when water is unsafe or dirty, it cannot be used for the purpose for which it is intended Water is tasteless, water is colourlessCalcium tetraoxosulphate(vi), Magnesium tetraoxo sulphate (vi) and Calcium hydrogen trioxocarbonateThe unit of force newton is a derived unit.Why?
Answer:
Why is the unit of force called a derived unit? That's because the Newton is defined in terms of other units which are more fundamental. One Newton is the force required to accelerate a mass of one kilogramme at the rate of one metre per second squared.
PLEASE HELP URGENT!!
What is the SI system? What are its benefits?
Answer:
The SI system : The international system of units.
It is a scientific method of expressing the magnitudes or quantities of important natural phenomena.
Benefits of SI system
It is a coherent system of units ( a system based on certain sets of fundamental units )It is a rational system of units ( it assigns only one unit to a particular physical quantity )3.0 cm x 4.0 cm x 1.0 cm
[?]cm^3
Explanation:
Hi there!!
you asked to multiply these all right,
you can simply multiply it ,
=3cm × 4 cm × 1cm
= 12cm^2×1cm (4×3=12)
= 12cm^3 (12×1=12)
Therefore, theanswer is 12 cm^3.
Hope it helps..