Answer:
A.
Explanation:
A 0.500-g sample containing Na2CO3 plus inert matter is analyzed by adding 50.0 mL of 0.100 M HCl, a slight excess, boiling to remove CO2, and then back-titrating the excess acid with 0.100 M NaOH. If 5.6 mL NaOH is required for the back-titration, what is the percent Na2CO3 in the sample?
The percentage by mass of Na2CO3 in the sample is 48%.
The equation of the reaction of Na2CO3 with HCl;
Na2CO3(aq) + 2HCl(aq) ------> 2NaCl(aq) + H2O(l) + CO2(g)
Since the HCl is in excess, the excess is back titrated with NaOH as follows;
NaOH (aq) + HCl(aq) ---->NaCl(aq) + H2O(l)
Number of moles of HCl added = 0.100 M × 50/1000 L = 0.005 moles
Number of moles of NaOH added = 5.6/1000 × 0.100 M = 0.00056 moles
Since the reaction of NaOH and NaOH is 1:1, 0.00056 moles of HCl reacted with excess HCl.
Amount of HCl that reacted with Na2CO3 = 0.005 moles - 0.00056 moles = 0.0044 moles
Now;
1 mole of Na2CO3 reacts with 2 moles of HCl
x moles of Na2CO3 reacts with 0.0044 moles of HCl
x = 1 mole × 0.0044 moles / 2 moles
x = 0.0022 moles
Mass of Na2CO3 reacted = 0.0022 moles × 106 g/mol = 0.24 g
Percentage of Na2CO3 in the sample = 0.24 g/ 0.500-g × 100/1 = 48%
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NEED ANSWER ASAP ! WILL BRAINLIST !
• Cillian is a company that uses a particular kind of wood to manufacture its products. Suppose the economy is experiencing high demand for trees from which this wood is obtained.
• Which is a likely response to this rising demand?
A. New distribution systems will be used to improve delivery of the wood to Cillian.
B. The trees will be regulated to maintain the availability of the wood.
C. New processes will be developed to locate the trees more efficiently.
D. The wood will be used as quickly as possible.
What is the atomic number of an oxygen atom that has 8 protons in its nucleus? 4 6 8 12
Answer:
8
Explanation:
f an oxygen atom has 8 protons and 8 neutrons in the nucleus, what is the atomic number? 8
d. The animals such as snakes and tortoises are called reptilians. Why?
Answer:
Explanation : Reptiles are cold blooded animals, have scales on their body (instead of hair or fur) and are usually egg laying. (certain viper types and boas give birth to live young). So that is what makes animals reptiles.
Reptiles are cold-blooded creatures that often lay eggs and have scales on their bodies rather than hair or fur. (Some types of vipers and boas give birth to live young).
Due to these reasons animals are reptiles.
What are reptiles?
Air-breathing vertebrates known as reptiles have unique skin consisting of scales, bony plates, or a combination of the two.They comprise of tortoises, turtles, lizards, snakes, and crocodiles.All of them periodically shed their skin's outer covering. The temperature of their environment affects how they function.Reptiles do not maintain a steady internal body temperature, in contrast to birds and mammals. They cannot stay warm on a chilly day without fur or feathers, and they cannot cool themselves on a hot day without sweat glands or the ability to pant. Instead, they shift as needed between the sun and the shade. They stop moving around when the weather becomes colder. Reptiles are cold-blooded due to their slow metabolic rate and heat-seeking habit.
Thus, it can be concluded that animals such as snakes and tortoises are called reptilians.
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#SPJ2
grtdggddgdggrsggrgrgd
Answer:
wut??
Explanation:
How many grams of CaSO4 form when
50.0 mL of 0.20 M Ca(NO3)2 react with
excess potassium sulfate solution?
Ca(NO3)2 + K2SO4 → CaSO4 + 2KNO3
-
?] g CaSO4
Answer:
1.36g CaSO4 (FIXED THIS)Explanation:
.01 mol CaSO4 is the conversion factor between these values and now you just need to multiply it by the molar mass of .01 x 136.14=1.36g CaSO4
Apologies for having the wrong answer before this, it's been a long day.
1. a Use the valence electron molecular orbital diagram for F2 to propose ground state F2ions that satisfy the following conditions
(1.5 points) (i) A F2 ion that is paramagnetic and that has a non-integer bond order.
(1.5 points) (ii) A F2 ion that is paramagnetic and that has an integer bond order.
(1.5 points) (iii) A F2 ion that is diamagnetic and that has a bond order of 3.
Clearly show the charge on your ion, label all valence molecular orbitals, and show the corresponding electrons in their orbitals. Full calculations for bond orders must be included.
b) Using only the valence electron molecular orbital diagram for F2, is a ground state diamagnetic ion with a bond order of 2 possible? Write one or two sentences to explain why or why not.
17) An ethanol solution has a concentration of 0.500M. What volume in liters of this solution
would contain 8.0 moles of ethanol?
To calculate the Molar Concentration, we will find the molar concentration by dividing the moles by liters of water used in the solution. For example, the acetic acid here is completely dissolved in 1.25 L of water. Then divide 0.1665 moles by 1.25 L to get the molar concentration, which will be 0.1332 M.
Hope It Helpz(◕ᴥ◕)What is the momentum of a car if its mass 200kg and moving with a speed of 3m/s?
600 kg·m/s
Given:Mass = 200 kg
Velocity = 3 m/s
Power = Mass * Velocity = 200 kg * 3 m/s = 600 kg·m/s
What you see as you look up at the night sky depends on the weather, the time of year, your location, and how dark your surroundings are. The
---
and stars are the celestial objects most people can see in the night sky.
the [moon] and stars are what most people see.
K3PO4(aq)+MgCl2(aq)⟶
Answer:
6KCl(aq) + Mg3(PO4)2(s) ... balanced equation
Explanation:
Lithium has an atomic mass of 6.941 amu. Lithium has two isotopes. One isotopes has a mass of 6.015 amu with a relative abundance of 7.49%. What is the mass of the other isotopes?
Explanation:
List the known and unknown quantities and plan the problem. Change each percent abundance into decimal form by dividing by 100. Multiply this value by the atomic mass of that isotope. Add together for each isotope to get the average atomic mass.
Answer:
The atomic mass of second isotope is 7.016
Explanation:
Given data:
Average Atomic mass of lithium = 6.941 amu
Atomic mass of first isotope = 6.015 amu
Relative abundance of first isotope = 7.49%
Abundance of second isotope = ?
Atomic mass of other isotope = ?
Solution:
Total abundance = 100%
100 - 7.49 = 92.51%
percentage abundance of second isotope = 92.51%
Now we will calculate the mass if second isotope.
Average atomic mass of lithium = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
6.941 = (6.015×7.49)+(x×92.51) /100
6.941 = 45.05235 + (x92.51) / 100
6.941×100 = 45.05235 + (x92.51)
694.1 - 45.05235 = (x92.51)
649.04765 = x 92.51
x = 485.583 /92.51
x = 7.016
The atomic mass of second isotope is 7.016
____________________________________________________
(Hope this helps can I pls have brainlist (crown)☺️)
convert 3.79 x 10^24 atoms of sodium to grams
mol = 3.79 × 10^24/6.02 × 10^23 = 6.296 mol
mass = 6.296 × 23 = 144.808 grams
1) Which statement best describes the usefulness of a model to investigate molecules at the microscopic level?(1 point)
A model’s usefulness depends on whether direct observations of phenomena can be made.
All models are useful.
A model’s usefulness depends on the accuracy of its predictions.
Models are not useful at all.
2) Which scientist contributed to molecular theory by explaining that gas pressure is caused by the impact of gas molecules on surfaces?(1 point)
Daniel Bernoulli
Amedeo Avogadro
John Dalton
Robert Boyle
3) Which term did Avogadro create?(1 point)
molecule
microscope
kinetic energy
atom
4) Which statement best describes the development of theories that connected microscopic and macroscopic phenomena?(1 point)
It took several hundred years for scientists to develop current theories, and they are essentially concrete.
It only took a few decades for scientists to develop current theories, and they are still being revised to this day.
It only took a few decades for scientists to develop current theories, and they are essentially concrete.
It took several hundred years for scientists to develop current theories, and they are still being revised to this day.
5) How can the results of experiments investigating the relationship between microscopic and macroscopic phenomena affect a model of molecular theory?(1 point)
Consistent results support the validity of the model, while inconsistent results require throwing out the model entirely.
Consistent results require throwing out the model entirely, while inconsistent results support the validity of the model.
Consistent results support the validity of the model, while inconsistent results indicate the need to modify the model.
Consistent results indicate the need to modify the model, while inconsistent results support the validity of the model.
Answer:
1. A model’s usefulness depends on the accuracy of its predictions.
2. Daniel Bernoulli
3. molecule
4. It took several hundred years for scientists to develop current theories, and they are still being revised to this day.
5. Consistent results support the validity of the model, while inconsistent results indicate the need to modify the model.
Explanation:
The discovery that macroscopic and microscopic phenomena are connected took several hundred years.
A model is a representation of a real life system that serves as a tool for predictions and explanation. Since models serve a predictive purpose, a model’s usefulness depends on the accuracy of its predictions.
The pressure of a gas is caused by the collision of gas molecules with the walls of the container. This was established by the scientist called Daniel Bernoulli.
Avogadro was able to create the term molecule to describe a substance that has independent existence. The discovery that macroscopic and microscopic phenomena are connected took several hundred years. It took several hundred years for scientists to develop current theories, and they are still being revised to this day.
The results of experiments investigating the relationship between microscopic and macroscopic phenomena affect a model of molecular theory in the sense that consistent results support the validity of the model, while inconsistent results indicate the need to modify the model.
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How are prisms and raindrops alike?
They are both transparent.
They both reflect white light.
They are both translucent.
They both refract white light.
they both refract white light.
Answer:
They both reflect white light.
Explanation:
How raindrops and prism are similar?
Raindrops and prisms are similar because they both cause light to bend when it enters a prism or raindrop. When light enters a raindrop it causes the light to bend (refract) and separates the white lights into different wavelengths, allowing us to see the individual colors of the rainbow.
How many ml of a 2.903 M NaOH solution are needed to produce 500.0 ml of a 0.3344M solution?
Answer:
57.6ml
Explanation:
Using dilution formula
C1V1 = C2V2
C1 = 2.903 M, V1 = ? , C2 = 0.3344 M , V2 = 500ml
2.903 × V1 = 0.3344 × 500
V1 =( 0.3344 × 500)/ 2.903
= 57.5956
≈ 57.6ml
The metal which burns with a white dazzling flame is:
a) silver
b) magnesium
c) gold
d) aluminum
Answer:
MagnesiumMagnesium burns with a dazzling white flame to form magnesium oxide a powdery mass.
Explanation:
Hope this helps you !!Answer:
b) Magnesium
Explanation:
According to G double O gle, it doesn't react with cold water but reacts to hot water/steam to form magnesium. Hydroxide and Hydrogen gas is released into the air!
How can a redox reaction be identified?
O A. Atoms have rearranged.
O B. Protons have been transferred.
.
O
C. lons are present in solution.
D. Oxidation states have changed.
Answer:
'Oxidation states have changed.'
Explanation:
Redox Reactions can be identifiable by a change in oxidation number/states of two of the atoms in the reaction. Any reaction in which no oxidation numbers/state change is not a redox reaction.
A student is studying the boiling points of six different liquids and finds results with consistently higher boiling points than what research would suggest. Which option describes a likely cause?
Answer:
Large molecules tend to have greater boiling points because the London dispersion forces are stronger within.
Explanation:
_________.__________ and___________ are energy science
Answer:
Chemical, Mechanical, and Nuclear Energy
Explanation:
Consider a 0.241 M aqueous solution of sodium hydroxide, NaOH.
A. How many grams of NaOH are dissolved in 24.43 mL?
B. How many individual hydroxide ions (OH-) are found in 24.43 mL?
C. How many moles of sulfuric acid, H2SO4, are neutralized by 24.43 mL of 0.241 M NaOH(aq)?
Answer:
a. 0.2355052g
Explanation:
a)
1000ml of NaOH contain 0.241moles
24.43ml of NaOH contain (24.43*0.241)/1000 moles
= 0.00588763moles
Relative Molecular Mass of NaOH
= 1*23 + 1*16 + 1*1
= 40
1mole of NaOH weighs 40g
0.00588763moles weigh (0.00588763*40) g
= 0.2355052g
B)
NaOH -> Na+ + -OH
1 mole of NaOH dissociates to form 1 mole of -OH ions
1 mole of a substance contains 6.02*10^23 particles(atoms)
= 0.00588763 * 6.02 *10^23
= ______ions
Based on the electron configuration of the two
atoms, predict the ratio of metal cationic (+) atom
to nonmetal anionic (-) atom in the compound.
Hydrogen 1s
Fluorine 1s22s22p5
A. 2:3
B. 1:2
C. 1:1
D. 3:2
Answer:
1 per 2 berarti a.2:3 berarti bagi bagi 1 22. 22 sama dengan 5
What is the interaction between atmosphere and biosphere
Answer:
Biosphere-Atmosphere Interactions focuses on the sources and sinks of greenhouse gases (GHGs), air pollutants, particulate matter, water, and energy between the Earth's surface and the atmosphere.
Explanation:
Select the correct answer. What does the kinetic theory state about the relationship between the speed and temperature of gas molecules? A. As the temperature increases, the speed of gas molecules remains constant. B. As the temperature increases, the speed of gas molecules decreases. C. As the temperature increases, the speed of gas molecules increases. D. As the speed of gas molecules increases, the temperature becomes constant. E. As the temperature decreases, the speed of gas molecules increases.
Answer:
C. As the temperature increases,the speed of gas molecules increase.
The specific heat of water is 4.184 J/gºC. How much energy (in
joules) is required to raise the temperature of 18g of H2O from
283K to 293K?
Industrial chemists have to understand the chemistry of oxides.
For example, silicon dioxide is used in glass making and carbon monoxide is used in the
extraction of iron from iron ore.
(i) Explain how burning carbon in air can lead to the formation of carbon monoxide.
(2)
(ii) Write the balanced equation for the reaction between silicon and oxygen.
(2)
Answer:
carbon monoxide can be formed due to incomplete combustion of carbon due to insufficient oxygen supply
2C+O2___2CO
Si+O2____SiO2
Electrical bonding refunding quick check!!
A team wants to understand the effects of molecular weight on boiling point. The team has access to five substances with
different molecular weights and the time to measure 50 boiling points. How can the team make the best use of the laboratory
testing time? (1 point)
O by taking 10 measurements of each of the five liquids and using the highest value from each set
O by taking 10 measurements of each of the five liquids and finding an average
O by taking measurements of the liquids one at a time, making sure that the correct results are achieved before
moving on to another liquid
O by taking one measurement of each liquid and then working to improve the least certain liquid in the group
Answer:
1. More data should be collected to get a more reliable average
2. A boiling point at 1.5 atmospheres could be predicted fairly well
3. The actual boiling point is probably between 34 C and 40 C
4. By taking 10 measurements of each of the five liquids and finding an average
5. The thermometer being used might need to be recalibrated
Explanation:
Took the quick check
The model below shows the equation that represents how hydrogen and oxygen combine to form water. In this chemical reaction, the reactants
are hydrogen gas and oxygen gas.
2H2 + O2 + 2H2O
True
False
Answer:
true
Explanation:
because they are balance
How many ml of a 2.903 M NaOH solution are needed to produce 500.0 ml of a 0.3344M solution?
Answer:
About 57.60 mL.
Explanation:
We can utilize the dilution equation:
[tex]\displaystyle M_1V_1 = M_2V_2[/tex]
Where M are the molarities of the solutions and V are the volumes of the solutions.
We want to determine the volume of a 2.903 M NaOH solution to mix in order to produce 500.0 mL of a 0.3344 M solution.
Substitute and solve for V₁:
[tex]\displaystyle \begin{aligned} (2.903 \text{ M})V_1 & = (0.3344 \text{ M})(500.0 \text{ mL}) \\ \\ V_1 & = 57.60\text{ mL} \end{aligned}[/tex]
In conclusion, 57.60 mL of a 2.903 M NaOH solution is needed.
in a test trial, using 6% extra strength bleach at room temperature, 100.0 mL of oxygen gas was produced in 2.03 seconds. Calculate the average reaction rate for the oxygen gas.
The average reaction rate for oxygen gas is 49.26 mL/s
The average reaction rate of a substance refers to the speed at which a reaction occurs and therefore products are formed. In the reaction presented, oxygen gas is the product.
Moreover, the average reaction rate can be expressed in mL per second or mL/s, and the formula to calculate it is:
Product in mL/seconds
Let's calculate the reaction rate:
100 mL/ 2.03 s = 49.26 mL/sLearn more about oxygen in: https://brainly.com/question/1506082