Answer:
1.24mol
Explanation:
m(MgO)=50g
molar mass=40.30g/mol (i search in google coz dosnt have book)
n=mass/molar mass
=50/40.30
=1.24mol
1. Calculate the pH of a 0.35 mol/L solution of ammonia.
Answer:
Explanation:
NH3 + H2O ⇌ NH4 + OH-
0.35 0.35
-log[OH-] = -log0.35 = 0.46 = pOH
14 - 0.46 = 13.54 = pH
explain why an indicator is used in titration
Answer:
Titrations. Because a noticeable pH change occurs near the equivalence point of acid-base titrations, an indicator can be used to signal the end of a titration. When selecting an indicator for acid-base titrations, choose an indicator whose pH range falls within the pH change of the reaction.
Hope it helped!!
which of these methods could are used to separate an insoluble solid and soluble solid
Answer:
To separate an insoluble solid from a soluble solid: Mixing the mixture with water, filtering out the insoluble solid, and then evaporating the water to isolate the soluble solid.
Explanation:
A 14.00-g piece of iron absorbs 1000 joules of heat energy, and its temperature changes from 25°C to 125°C. Calculate the specific heat capacity of iron.
Answer:
THE SPECIFIC HEAT OF IRON IS 0.714 J/g °C
Explanation:
Heat absorbed = 1000 J
Mass of the piece of iron = 14 g
Temeperature changes = ( 125-25)°C= 100°C
specific heat of iron = unknown
To find the specific heat of iron in the question use the formula of heat
Heat = mass * specific heat * temperature change
Specific heat = Heat / mass * temperature change
Specific heat = 1000 / 14 * 100
Specific heat = 1000 / 1400
Specific heat = 0.714 J/g °C
So therefore, the specific heat of iron is 0.714 J/g °C
Which of the following is true for a gas under conditions of very low temperature? PV ÷ nRT = 1, because all gases behave ideally at very low temperatures. PV ÷ nRT = 1, because the actual volume of the gas molecules becomes considerable. PV ÷ nRT > 1, because the low temperatures speed up the particles. PV ÷ nRT < 1, because particles are unable to overcome intermolecular attractions.
please answer in details. what class of carbon is coal
50 points - I need this really soon! plz help
The pictured compound has which bond?
A.) C = C and C −C
B.) C = C and C −H
C.) C −Cand C −H
D.) C −C, C −H, and C −O
Answer:
C.
Explanation:
Butane (C4H10) has 3 C-C bonds in the carbon chain and 10 C-H bonds
Butane ([tex]C_4H_10[/tex]) has 3 C-C bonds in the carbon chain and 10 C-H bonds
What is alkane?Alkanes are saturated hydrocarbons. This means that their carbon atoms are joined to each other by single bonds.
Based on the diagram, butane is considered to be an alkane. It not only contains single covalent bonds, but also has carbon and hydrogen atoms present in its structure.
When comparing both structures to one another, isobutane is a branched chain, while butane is a linear chain.
Learn more about alkane here:
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Calculate the Molarity of a 0.23 mole solution of sucrose, C 12 H 22 O 11 that is dissolved in 5 liters of water.
Answer:
0.046 M
Explanation:
Molarity = mol solute/ L solution = 0.23 mol/ 5 L = 0.046 mol/L = 0.046 M
4. Why does ammonia, NH3, behave as a base when it reacts with an acid?
A It accepts a neutron and becomes NH3+.
B It accepts a proton and becomes NH4+.
OC It donates a proton and becomes NH2
B is the answer ,ammonium accepts a proton and becomes ammonium ion
Which structure below contains all of the others?
DNA
gene
chromosome
nucleus
Answer:
nucleus
Explanation:
The nucleus holds all the other things, keeping them safe and confined.
Answer:
Nucleus
Explanation:
It contains DNA which contains a GENE which contains a CHROMOSOME so its NUCLEUS
If the temperature outside increases, but the amount of water vapor stays the same, what happens to the relative humidity? (50 points, please explain)
If the water vapor content remains the same and the temperature decreases, the relative humidity rises.
If the water vapor content remains the same and the temperature increases, the relative humidity falls.
This is because colder air doesn’t need as much moisture to become saturated as warmer air.
Hope this helps
Describe one way in which uranium is disposed of.
Answer:
In the oxide form, uranium can be disposed of as low-level radioactive waste at an approved disposal facility. Approximately 350,000 tons of anhydrous HF are used annually in the United States.
Explanation:
7. What volume of a 0.10 mol/l HCl solution is needed to neutralize 10 ml of a 0.15
mol/l LiOH solution (5 points)
Answer: The volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml
Explanation:
To calculate the volume of acid, we use the equation given by neutralization reaction:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid which is [tex]HCl[/tex]
[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is LiOH.
We are given:
[tex]n_1=1\\M_1=0.10mol/L\\V_1=?mL\\n_2=1\\M_2=0.15mol/L\\V_2=10mL[/tex]
Putting values in above equation, we get:
[tex]1\times 0.10\times V_1=1\times 0.15\times 10\\\\V_1=15mL[/tex]
Thus the volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml
Why would cooking equipment be responsible for more total fires but smoking smoking responsible for more fire deaths?
Answer:
For the last few decades fires started by any type of smoking material has been the number one leading cause for household fire fatalities. It could just be that people luckily escape in time with cooking equipment fires, and smoking related fires just result in more deaths.
Which of he following is a secondary alkanol?
a. CH3CH2CH2OH
b. CH3CH2CH2CH2OH
c. C(CH3)3OH
d. CH3CH(OH)CH3
Answer: Thus [tex]CH_3CH(OH)CH_3[/tex] is a secondary alkanol.
Explanation:
Alkanol are compounds which contains carbons bonded by single bonds and contains hydroxy (-OH) as functional group.
Primary alkanol are those compounds which contain hydroxyl group attached a carbon which is further attached to a single carbon atom. Example: [tex]CH_3CH_2CH_2OH[/tex] and [tex]CH_3CH_2CH_2CH_2OH[/tex]
Secondary alkanol are those compounds which contain hydroxyl group attached to a carbon which is further attached to two more carbon atoms.Example: [tex]CH_3CH(OH)CH_3[/tex]
Tertiary alkanol are those compounds which contain hydroxyl group attached to a carbon which is further attached to three more carbon atoms. Example: [tex]C(CH_3)_3OH[/tex]
Thus [tex]CH_3CH(OH)CH_3[/tex] is a secondary alkanol.
How marly electrons are in an atom of elemental
sodium?
Answer: 11 Electrons
Explanation:
We know that the atomic number of sodium is 11. This tells us that sodium has 11 protons and because it is neutral it has 11 electrons.
Answer:
The sodium atom is left with a full outermost electron shell with eight electrons, and the outermost shell of the other atom is full as well.
Explanation:
The sodium atom now has a positive electrical charge of plus 1, and the other atom has a negative charge of minus 1. The two opposite charges attract, and the two atoms now form the molecule of a compound.
Why are prefixes often added to SI units?
Answer: SI prefixes are used to form decimal multiples and submultiples of SI units. They should be used to avoid very large or very small numeric values.
Explanation: ^^^
What is one way to make stored water safe?
Even though you asked for ONE WAY, I found some other good ways.
1. Thoroughly wash plastic soda bottles or milk jugs with warm, soapy water.
2. Store sealed containers in a dark, dry, and cool place.
3. If after six months you have not used the stored water, empty it from the containers and repeat steps 1 through 3 above.
Potassium atoms contribute one eletron to metallic bonding,but calcium atoms contribute two eletrons .Explain which metal is likely to be harder
Answer:
potassium is likely to be harder
Explanation:
because whenan atom loss electron they can form particle ion acquare stable a arrangement that loos electron can transfer to another which that also to acquaire stable
What is the chemical name of the covalent compound P4O9? A. tetraphosphorus nonaoxygen B. tetraphosphate nonoxygen C. tetraphosphide nonaoxide D. tetraphosphorus nonoxides.
Answer: The chemical name of the covalent compound [tex]P_4O_9[/tex] is, tetraphosphorous nonaoxide.
Explanation:
A covalent compound is a compound where the sharing of electrons takes place between elements where both the elements are non-metals.
The naming of covalent compound is given by:
1. The less electronegative element is written first.
2. The more electronegative element is written second. Then a suffix is added with it. The suffix added is '-ide'.
3. If atoms of an element is greater than 1, then prefixes are added which are 'mono' for 1 atom, 'di' for 2 atoms, 'tri' for 3 atoms and so on.
Hence, the correct name for the compound [tex]P_4O_9[/tex] which is a covalent compound is, tetraphosphorous nonaoxide.
Difference between rapid combustion and spontaneous combustion.
Answer: The difference between rapid combustion and spontaneous combustion...
Explanation:
Rapid combustion is a form of combustion, otherwise known as a fire, in which large amounts of heat and light energy are released, which often results in a flame.Whereas spontaneous combustion is the ignition of organic matter (e.g. hay or coal) without apparent cause, typically through heat generated internally by rapid oxidation.
What shape would a molecule with two bound groups and two lone pairs
have?
A. Trigonal pyramidal
B. Tetrahedral
C. Linear
D. Bent
Answer:
It would have to be D, a bent shape
Explanation:
I just took the quiz
what is the difference between an exothermic and endothermic reaction.
Answer:
An endothermic reaction takes in heat, but feels cold to the touch. An exothermic reaction gives off heat and feels warm to the touch because it is heating the outside objects.
20 points!! Please help me! Will mark Brainliest!! complete the following word equations:) also write the balanced equation, full ionic equation, and net ionic equation. Also include the states:)
a) zinc nitrate + calcium sulphide—>
b) potassium + calcium chloride—>
If 1.50 L of 0.780 mol/L sodium sulfide is mixed with 1.00 L of a 3.31 mol/L lead(II) nitrate solution, what mass of precipitate would you expect to form?
Answer:
336.1 g of PbS precipitate
Explanation:
The equation of the reaction is given as;
Na2S(aq) + Pb(NO3)2(aq) ----> 2NaNO3(aq) + PbS(s)
Ionically;
Pb^2+(aq) + S^2-(aq) -----> PbS(s)
Number of moles of sodium sulphide= concentration of sodium sulphide × volume of sodium sulphide
Number of moles of sodium sulphide= 0.780 × 1.5 = 1.17 moles
Number of moles of lead II nitrate= concentration of lead II nitrate × volume of lead II nitrate
Number of moles of lead II nitrate= 3.31× 1.00= 3.31 moles
Then we determine the limiting reactant. The limiting reactant yields the least amount of product.
Since 1 moles of sodium sulphide yields 1 mole of lead II sulphide
1.17 moles of sodium sulphide also yields 1.17 moles of lead II sulphide
Hence sodium sulphide is the limiting reactant.
Thus mass of precipitate formed= amount of lead II sulphide × molar mass of sodium sulphide
Molar mass of lead II sulphide= 287.26 g/mol
Mass of lead II sulphide = 1.17 moles × 287.26 g/mol
Mass of lead II sulphide= 336.1 g of PbS precipitate
Which of the following statements are true? Significant figures in a measurement are all measured digits, and one estimated digit None of the above Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements
Answer: Significant figures in a measurement are all measured digits, and one estimated digit
Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements.
Explanation:
Significant figures : The figures in a number which express the value or the magnitude of a quantity to a specific degree of accuracy or precision is known as significant digits.
The significant figures of a measured quantity are defined as all the digits known with certainty and the first uncertain or estimated digit.
Rules for significant figures:
1. Digits from 1 to 9 are always significant and have infinite number of significant figures.
2. All non-zero numbers are always significant.
3. All zero’s between integers are always significant.
4. All zero’s preceding the first integers are never significant.
5. All zero’s after the decimal point are always significant.
The true statements are
Significant figures in measurement are all measured digits, and one estimated digit
Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements.
The following information should be considered:
The figures in a number that express the value or the magnitude of a quantity is known as significant digits.The significant figures of a measured quantity refers to all the digits known with certainty.Learn more: https://brainly.com/question/1979431?referrer=searchResults
PLEASE HELP CHEM BABES I HAVE BEEN CRYING FOR A WHILE NOW
1. Calculate the mass of nitrogen dioxide (NO2) present in a 0.831 L container if the pressure is 100 kPa at a temperature of 27 oC. R = 8.31 kPa x L / mol x K. (K = oC + 273).
2. A 33.2 L tank contains 280 g of compressed helium. If the pressure inside the tank is 700.0 kPa, what is the temperature of the compressed gas? You must convert the mass of helium into moles using the molar mass of He. The conversion factor will be 1 mol / molar mass of helium. R = 8.31 kPa x L / mol x K
Answer: See below
Explanation:
1. To calculate the mass, you know you can convert by using molar mass. Since mass is in grams, we can use molar mass to convert moles to grams. This calls for the Ideal Gas Law.
Ideal Gas Law: PV=nRT
We manipulate the equation so that we are solving for moles, then convert moles to grams.
n=PV/RT
P= 100 kPa
V= 0.831 L
R= 8.31 kPa*L/mol*K
T= 27°C+273= 300 K
Now that we have our values listed, we can plug in to find moles.
[tex]n=\frac{(100kPa)(0.831L)}{(8.31kPa*l/molK)(300K)}[/tex]
[tex]n=0.033mol[/tex]
We use the molar mass of NO₂ to find grams.
[tex]0.033mol*\frac{46.005g}{1mol }=1.52 g[/tex]
The mass is 1.52 g.
2. To calculate the temperature, we need to use the Ideal Gas Law.
Ideal Gas Law: PV=nRT
We can manipulate the equation so that we are solving for temperature.
T=PV/nR
P= 700.0 kPa
V= 33.2 L
R= 8.31 kPa*L/mol*K
n= 70 mol
Now that we have our values, we can plug in and solve for temperature.
[tex]T=\frac{(700kPa)(33.2L)}{(70mol)(8.31 kPa*L/molK)}[/tex]
[tex]T=40K[/tex]
The temperature is 40 K.
the vessel in which electrolysis takes place is called
PLEASE GUYS ANSWER IT
What is sodium bicarbonate an example of? a buffer an acid a liquid a base
Answer:
base
Explanation:
carbonic acid - H2CO3 - is a weak acid. Therefore, HCO3 itself is its conjugate base. The Na(sodium) ion is neutral.
This means that NaHCO3 is a base. (a weak one)
I NEED HELP PLEASE, THANKS SO MUCH! :)
Solids, liquids and gases are the three most commonly accepted phases of matter. Explain the properties of each phase, including their relative energy.
Answer:
Here's what I get
Explanation:
The molecules of a substance attract each other.
They are also in constant motion.
Their kinetic energy increases with the temperature.
1. Solids
If the temperature is low enough, the molecules will have little kinetic energy.
They will not be able to escape the attractions of their neighbours, so they will be fixed in place in a crystalline array.
All they can do is vibrate about their position in the array.
The substance will be a solid.
2. Liquids
If the temperature is higher, the molecules will have enough kinetic energy to slide past each other, but not enough to escape the attractions of nearby molecules.
The substance will be a liquid.
3. Gases
If the temperature is high enough, the molecules will have enough kinetic energy to escape from the surface and fly off into space.
The molecules will on average so far apart that they won't feel the attractions of others.
When they do collide, they will have energy to bounce off each other rather than stick together.
The substance will be a gas.
