calculate the mass of magnesium needed to make 25g of magnesium oxide
mark brainliest of correct xx
Answer:
15g
Explanation:
First, you need to correct the answer to the previous question. The percentage by mass of Mg in MgO =
Mg = 24.3 amu
O = 16.0 amu
The total mass of MgO = 40.3 amu
To calculate the percent composition of Mg:
% = 24.3/40.3 x 100
% = 60
To calculate the mass of Mg needed to make 25g of MgO:
x/25g = 60%/100%
100x = (25)(60)
100x = 1500
x = 15g
Analysis of an ore of calcium shows that it contains 13.61 g calcium and 21.77 g oxygen in a 46.28-g sample. Calculate the percent composition of this compound.
Answer:
29.41% of Calcium and 47.04% of Oxygen
Explanation:
The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.
The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:
13.61g / 46.28g * 100 = 29.41% of Calcium
And percent composition of Oxygen is:
21.77g / 46.28g * 100 = 47.04% of Oxygen
Which is the formula mass of (NH4)2SO4?
96.07 amu
114.12 amu
116.17 amu
132.17 amu
Answer:
132.17amu
Explanation:
(14.01+1.01 multiplied by 4)=18.05×2=36.1
36.1+32.07= 68.17
16.00×4=64
68.17+64=132.17
Answer:
132.17 amu
Explanation:
just took the test. got 100
Consider the reaction. 2HF(g)—H2(g)+F2(g). What is the value of Keq for the reaction expressed in scientific notation
Answer:
A). 2.1 × [tex]10^{-2}[/tex]
Explanation:
Given reaction,
2[tex]HF[/tex] (g) ⇄ [tex]H_{2}[/tex] (g) + [tex]F_{2}[/tex] (g)
The concentrations are as following;
[tex]HF[/tex] = 5.82 × [tex]10^{-2}[/tex] M
[tex]H_{2}[/tex] = 8.4 × [tex]10^{-3}[/tex] M
[tex]F_{2}[/tex] = 8.4 × [tex]10^{-3}[/tex] M
So,
[tex]K_{eq}[/tex] = [([tex]H_{2}[/tex] ) × ([tex]F_{2}[/tex])] ÷ [[tex]HF[/tex]]^2
Now,
We can determine the value of [tex]K_{eq}[/tex] by substituting the values in above formula:
[tex]K_{eq}[/tex] = [ (8.4 × [tex]10^{-3}[/tex] M) × (8.4 × [tex]10^{-3}[/tex] M)] ÷ [(5.82 × [tex]10^{-2}[/tex])^2
= 2.08 * [tex]10^{-2}[/tex]
= 2.1 × [tex]10^{-2}[/tex]
∵ [tex]K_{eq}[/tex] = 2.1 × [tex]10^{-2}[/tex]
Thus, option A is the correct answer.
HELP ME ASAPPPP PLZZZZZ!!!!!
For the reaction C + 2H2 → CH4, how many grams of hydrogen are required to produce 16.8 moles of methane, CH4 ?
Plz Help I have One more time To retake and I can't fail it..
Answer:
A
Explanation:
Hydrogen bonds are intermolecular forces of interaction that exist between molecules of a substance in which hydrogen is bonded to a highly electronegative atom. Hydrogen bonds are strong intermolecular forces and account for high melting and boiling points of small molecules such as water. They stem from dipole-dipole interaction between molecules of a substance.
Metallic bonds are bond forces which exist in a metal. Metal cations are held together by a sea of electrons via electrostatic interaction.
The ionic bond is formed by transfer of electrons from one atom to another leading to the formation of an ion pair held together by electrostatic attraction.
Metallic bonds and hydrogen bonds are much weaker than ionic bonds. Ionic compounds are known to have high melting and boiling points.
Brainliest if answered correctly
How many Calcium (CA) atoms are in carbon tetrachloride
Answer:
What atoms are present in carbon tetrachloride?
There is 1 carbon, and 4 chlorine atoms (or chloride ions if you want to get technical). Tetra means 4 in Greek.
hope that helps❤
Answer:
there are no calcium atoms of n carbon tetrachloride
The graph shows the change in concentration of one of the species in the reaction
A + B + C→D.
If the graph indicates the reaction rate, then the concentration of which species is plotted?
A
B
C
D
Answer:
its D
Explanation:
Took the test
The specie whose concentration is plotted is D. The rate of reaction is how quickly or slowly hat a reaction proceeds.
Rate of reactionThe term rate of reaction refers to how quickly or slowly hat a reaction proceeds. A reaction rate plot involves the concentration of the species plotted against time.
Now we can see from the plot that concentration is increasing with time. Since the concentration of products increases with time, then the specie whose concentration is plotted is D.
Learn more about rate of reaction: https://brainly.com/question/11256472
in which instrument of the following the washer works works as a valve? a)syringe b)hydraulic garage lift c)air pump d)watre pump
Answer:
A
Explanation:
The instrument in which the washer works as a valve is A ; syringe
Each instrument listed have a washer and a valve, but of all the instruments listed above the instrument that its washer works also as a valve is the syringe.
A syringe is composed of a thin tube and a thinner hollow needle attached to the end of the thin tube. the needle is used and take in liquids and also expel liquids from the syringe ( i.e. washer and valve )
hence the instrument that its washer also functions as a valve is the syringe.
learn more about syringe : https://brainly.com/question/24283167
why water molecules remain associated in liquid water
Answer:
Answer: They are attracted to each other due to their electrostatic attraction. All that means is the hydrogen atom is positively charged, while the oxygen atom is negatively charged. ... The hydrogen of one water molecule will bond to the oxygen atom of another molecule.
Answer:
They are attracted to each other due to their electrostatic attraction. All that means is the hydrogen atom is positively charged, while the oxygen atom is negatively charged. ... The hydrogen of one water molecule will bond to the oxygen atom of another molecule.
Explanation:
Answer in detail?? What precautions would you take to protect yourself from an earthquake, when you are at home and when you are outdoors?
Answer:
If you're indoors, stay inside. If you're outside, stay outside. If you're indoors, stand against a wall near the center of the building, stand in a doorway, or crawl under heavy furniture (a desk or table). Stay away from windows and outside doors.
Answer
Protect your head and neck with a large book, a pillow, or your arms. The goal is to prevent injuries from falling down or from objects that might fall or be thrown at you.If you are able, seek shelter under a sturdy table or desk. Stay away from outer walls, windows, fireplaces, and hanging objects.If you are unable to move from a bed or chair, protect yourself from falling objects by covering up with blankets and pillows.If you are outside, go to an open area away from trees, telephone poles, and buildings, and stay there.Using dobereiner's triads, what conclusion could have been made about magnesium
Answer:
Triads were groups of 3 elements with similar chemical and physical properties. Beryllium, magnesium, and calcium are all earth alkalis found in the earth
Explanation:
Please hurry this is due tomorrow morning
A student is studying the ways different elements are similar to one another. Diagrams of
atoms from four different elements are shown below.
Which two atoms are of elements in the same group in the periodic table?
F Atom 1 and Atom 2
G Atom 1 and Atom 4
H Atom 2 and Atom 3
J Atom 3 and Atom 4
What is the change in enthalpy of the first reaction below, given the enthalpies of the other two reactions?
Here's the reactions:
There was a formatting issue with the specific chemistry symbols, there all correct in the picture below
2C(s) + O2(g) → 2CO(g)
C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol
CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol
There was a formatting issue with the specific chemistry symbols, there all correct in the picture below
Answer:
∆H0 = -222kJ/mol
Explanation:
Using Hess's law, we can find the ΔH of a reaction from the sum of another related reactions as follows:
Using the reactions:
(1) C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol
(2) CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol
Twice (1):
2C(s) + 2O2(g) → 2CO2(g) ∆H0= 2*-394 KJ/mol = -788kJ/mol
The inverse reaction of (2):
-(2) CO2(g) → CO(g) + 1/2 O2(g) ∆H0= 283 KJ/mol
Twice this reaction:
2*-(2) 2CO2(g) → 2CO(s) + O2(g) ∆H0= 2*283 KJ/mol= 566kJ/mol
Now, the sum of 2*(1) - 2*(2) produce:
2C(s) + 2O2(g) + 2CO2(g)→ 2CO2(g) + 2CO(g) + O2(g) ∆H0= -788kJ/mol + 566kJ/mol
Subtracting the molecules that ar in both sides of the reaction:
2C(s) + O2(g) → 2CO(g) ∆H0 = -222kJ/mol
Name five metal which are both dilute and memorable? class 10
2. Nitric oxide contains 46.66% nitrogen and 53.34% oxygen. Water contains 11.21% hydrogen and 88.79% oxygen. Ammonia contains 17.78% hydroger and 82.22% nitrogen. Use these data to verify the law of reciprocal proportions.
Answer:
The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other
The compounds formed includes;
1) Nitric oxide, NO
Nitrogen = 46.66% × 30.01 = 14
Oxygen = 53.34% × 30.01 = 16
2) Water, H₂O
Hydrogen = 11.21% × 18.01528 = 2
Oxygen = 88.79% × 18.01528 ≈ 16
3) Ammonia, NH₃
Hydrogen = 17.78% × 17.031 ≈ 3
Nitrogen = 82.22% × 17.031 ≈ 14
The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8
The ratio of nitrogen to hydrogen in ammonia = 14:3
The ratio in which hydrogen and oxygen combine with nitrogen = 3/16
The ratio of hydrogen and oxygen combine with each other in water = 2/16
Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions
Explanation:
A galaxy that has an undefined shape is best classified as a(n)
galaxy.
Answer:
irregular galaxy
pls give brainliest :)
Answer:
irregular galaxy
it is undefined shape
Mole concept
Calculate the number of iodine atoms in 4.50g of iodine gas
Answer:
0.017g/mol
Explanation:
according to the mole concept to calculate the number of moles of a substance you use the formula
number of moles= mass/molecular mass
=4.5g/254g/mole
=0.017moles
I hope this helps and sorry if it's wrong
When a vacancy exists in an inner electron shell of an atom (as a result of photoelectric effect, Compton scattering, or bombardment by other electrons), the energy liberated when this vacancy is filled, instead of emerging from the atom as fluorescent radiation, can be transferred to another electron of the atom, thereby ejecting the electron. Such an emitted electron is called a(n) _____ electron
Answer:
The answer is "Auger".
Explanation:
The Auger effect is an effect size when the vacancy of even an atom throughout the inner shell was complemented by the release of even an electron from the same atom. Whenever a central electron is lost, a higher energy level electron can drop into the void and release energy, which can be the result.
A liquid that occupies a volume of 8.2L has a mass of 5.6kg. What is the density of the liquid in kg/L
Answer:
0.68
Explanation:
This is because the formula for finding density is mass/volume. Therefore the equation becomes 5.6/8.2 giving you 0.68
BJECTIVE TYPE QUESTIONS
Fill in the blank spaces by choosing the correct words from the words given in list.
List : composition, heat, chemical, photosynthesis, physical
1. Heating of zinc oxide is a
change.
2. Burning of coal is a
change.
3. There is a change in state and
during a chemical change.
4. Plants make their food by the process of
5.
energy is generally given out or absorbed during a chemical change
Answer:
1.Physical change
2. Chemical change
3. Heat
4.photosynthesis
5. composition
Match each lab incident to the item of PPE that will protect you from it. Each item of PPE will only be used once.
While picking up a buret, an unknown solution left by a previous solution drips onto your hand._______________
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor _______
While checking on a stirring solution, the solution splashes up towards your face. _______
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench, __________
A. Gloves
B. Lab coat
C. Goggles
D. Closed-toe shoes
While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes
While checking on a stirring solution, the solution splashes up towards your face - Goggles
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat
Explanation:
The full form of PPE is 'Personal Protective Equipment'.The PPE items we use in labs are : Lab coat: Protection of clothing and skin from accidental spilling of hot liquid or toxic substances. Gloves: Protection from hands from chemicals, hot objects, sharp tools, or electricityGoggles: Protection of the eye from any chemicals, toxic vapor, chemical debrisFace shield: Protection of the face from any chemicals, toxic vapor, chemical debrisClosed-toe shoes: Protection from feet from chemicals, hot objects, sharp tools, or electricitySo, according to the question. the matches will be:
While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes
While checking on a stirring solution, the solution splashes up towards your face - Goggles
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat
Learn more about PPE here:
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Which condition will probably not increase
the rate of reaction?
a. Adding water to dilute the reaction
mixture
b. Increasing the temperature
c. Adding a catalyst
d. Removing an oxide coating on a
metal
Answer:
i think A.
Explanation:
bc B. makes the molecules hight temp = move faster = more collisions = higher rate, C. it's use is to make reactions rates increase, D. somthung abt more surface area and easier collisions
Name the following bases.
Fe(OH)3
- iron(III) hydroxide
- iron(II) hydroxide
- iron hydroxide
Answer:
1
Explanation:
Ferric Hydroxide
3. 1
Fe. (OH)
Fe(OH)3
Answer:
iron(III) hydroxide
Explanation:
I just took the quiz!
can u plz solve it n send the answer
1. Cl2 + H2O → HOCl + HCl
2. Tooth decay starts when when the pH of the mouth is lower than 5.5. Tooth enamel is made up of calcium phosphate and it is one of the hardest substances of the body. But it is corroded when the pH is less than 5.5. The bacteria of our mouth produce acids by degradation of sugar and food particles remaining in our mouth after eating food.
3. Fluorine salts are added in toothpaste to protect our teeth from tooth decay. Fluorine salts are mildly basic, so they neutrelise the acid in our mouth that leads to tooth decay.
4. Tincture of iodine is iodine, pottasium iodide and sodium iodide dissolved in ethanol. Iodine acts in an antiseptic manner by destroying microbial proteins and DNA.
5. Tincture of iodine is clear and reddish brown liquid.
A process which is unfavorable with respect to enthalpy, but favorable with respect to entropy Group of answer choices could occur at high temperatures, but not at lower temperatures. could not occur regardless of temperature. could occur at any temperature. could occur at low temperatures, but not at higher temperatures. none of the above
Answer:
could occur at any temperature.
Explanation:
The spontaneity of a reaction is what determines whether the reaction will occur or not. A spontaneous reaction occurs easily.
The spontaneity of a reaction is predicted by the sign of ∆G.
When ∆G is positive, the reaction is not spontaneous. When ∆G is negative, the reaction is spontaneous.
Note that;
∆G= ∆H - T∆S
Where;
∆H = Change in enthalpy
∆S = Change in entropy
T= temperature
If ∆H is unfavourable and ∆S is favourable, the reaction can proceed at all temperatures because ∆G will always be negative.
It should be noted that a process that is unfavorable as regards to enthalpy, but favorable with respect to entropy could occur at any temperature.
Enthalpy(∆H) serves as amount of internal energy that a compound has, entropy( ∆S) on the other hand serves as intrinsic disorder within the system.
However, spontaneity of a reaction determines likely hood of occurrence of a reaction, when the process is spontaneous, it makes the reaction to occurs easily.
We can conclude that whenever enthalpy is unfavourable and entropy of a system is favourable, then the spontaneity will be negative and the reaction will occur at any temperature.
Learn more about entropy and enthalpy on;
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What was the main aim of Cavendish’s work?
Answer:
The Cavendish experiment, performed in 1797–1798 by English scientist Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory and the first to yield accurate values for the gravitational constant
Explanation:
I think that's correct
use the the dot strict on the right to and the periodic table to determine the element represented.
sodium (Na)
potassium (K)
neon (Ne)
argon (Ar)
Answer:
Pottasium
Explanation:
because it is the nineteenth element
Answer:
The answer is B. Potassium.
Explanation: Potassium has 19 electrons that are organized like the image if you count the electrons on each obital. This answer is correct on edge 2020. Hope this helps!
how do i calculate the concentration of a certain solution
Answer:
Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.
Ethylene glycol (antifreeze) has a density of 1.11 g/cm^3. What is the volume (in m^3) of 9.7 tons?(1 ton = 2.000*10^3lb; 1 kg= 2.2046 lb
Answer: The volume of 9.7 tons of given ethylene glycol is 0.0079 [tex]m^{3}[/tex].
Explanation:
Given: Density = 1.11 [tex]g/cm^{3}[/tex]
Mass = 9.7 tons
Convert tons into lb as follows.
[tex]1 ton = 2 \times 10^{3} lb\\9.7 ton = 9.7 ton \times 2 \times 10^{3} \frac{lb}{1 ton}\\= 19.4 \times 10^{3} lb[/tex]
Now, lb is converted into kg as follows.
[tex]1 kg = 2.2046 lb\\1 lb = 0.453592 kg\\19.4 \times 10^{3} lb = 19.4 \times 10^{3} lb \times 0.453592 \frac{kg}{1 lb}\\= 8.79 kg[/tex]
1 kg = 1000 g
So, 8.79 kg = 8790 g
Density is the mass of a substance divided by its volume. Hence, volume of ethylene glycol is calculated as follows.
[tex]Density = \frac{mass}{volume}\\1.11 g/cm^{3} = \frac{8790 g}{volume}\\volume = 7918.92 cm^{3} (1 cm^{3} = 10^{-6} m^{3})\\= 0.0079 m^{3}[/tex]
Thus, we can conclude that the volume of 9.7 tons of given ethylene glycol is 0.0079 [tex]m^{3}[/tex].
