Answer:
a chemical change is correct answer
A 14.1g sample of NaOH is dissolved in 200.0g of water in a coffee-cup colorimeter. The temperature increases from 20.0C to —-. Specific heat of liquid water is 4.18 J/g-K and deltaH for the dissolution of sodium hydroxide in water is 44.4kj/mol.
Answer:
The temperature finally increased from 20 °C to 38.7 °C
Explanation:
This a problem about calorimetry. Formula to solve it is:
Q = m . C . ΔT
Where ΔT is Final T° - Initial T°
m is the mass
and C, specific heat.
In this situation we are dissolving NaOH where 1 mol requires 44.4 kJ of heat. As we do not have 1 mol, we need to determine the heat that is released.
We convert the mass to moles
14.1 g . 1 mol / 40g = 0.3525 mol
We determine the heat
0.3525 mol . 44400 J/mol = 15651 Joules of heat.
Now we can replace data in the calorimetry formula:
15651 J = 200 g . 4.18 J/g°C (Final T° - 20°C)
15651 J / (200 g . 4.18 J/g°C) = Final T° - 20°C
18.7°C + 20°C = Final T° → 38.7°C
Which of the following is a strong base?
a. h2o
b. NH3
c.CaCo3
d. NaOh
Answer:
d. naoh
Explanation:
Describe what has to happen when matter is heated by convection
Answer:
Here^
Explanation:
The matter starts heating, up as if it's ice , turns into a liquid.
formula of preparation of sodium hydroxide
The chemical formula of sodium hydroxide is NaOH, and its molar mass is 40.01 g/mol. It is the alkali salt of sodium, and its structure is shown below:
It is an ionic compound consisting of sodium cation (Na+) and hydroxide (OH-) anion.
How many Cl- bond with one Na+ ion?
0.485 moles BaSO4 is equal to how many grams of BaSO4?
___ grams BaSO4
A chemist was working on a new treatment for nonliving infectious agents that are not curable. What type of infectious agent is the new medicine for?
A. Virus
B.Fungus
C.Parasite
D.Bacteria
Answer: D: bacteria
Explanation:
Which set of properties is most characteristic of transition elements?
Answer:
C.
Explanation:
Transition elements like, for example, iron:
Fe2+ green colored in solution.
Fe3+ brown colored in solution.
Write an expression for standard enthalpy of formation using suitable chemical reaction
What elements does lithium resemble when it loses 1 electron?
Answer:
helium
Explanation:
By losing an electron, they look like the noble gas that immediately precedes them on the periodic table.
PLZ HELP
11 and 12 :)))
Answer:
Explanation:
number 12 is magnesium i think which is group lla which is B alkaline earths
A mixture is best described as:
Help me answer this plz.
Answer:
87.58 L of C₂H₂
Explanation:
We'll begin by calculating the number of mole in 250 g of CaC₂.
This can be obtained as follow:
Mass of CaC₂ = 250 g
Molar mass of CaC₂ = 40 + (12×2)
= 40 + 24
= 64 g/mol
Mole of CaC₂ =?
Mole = mass /Molar mass
Mole of CaC₂ = 250 / 64
Mole of CaC₂ = 3.91 moles
Next, the balanced equation for the reaction. This is given below:
CaC₂ + 2H₂O —> C₂H₂ + Ca(OH)₂
From the balanced equation above,
1 mole of CaC₂ reacted to produce 1 mole of C₂H₂.
Next, we shall determine the number of mole of C₂H₂ produced by the reaction of 250 g (i.e 3.91 moles) of CaC₂. This can be obtained as follow:
From the balanced equation above,
1 mole of CaC₂ reacted to produce 1 mole of C₂H₂.
Therefore, 3.91 moles of CaC₂ will also react to produce 3.91 moles of C₂H₂.
Finally, we shall determine the volume of C₂H₂ produced from the reaction. This can be obtained as follow:
Recall:
1 mole of any gas occupy 22.4 L at STP.
1 mole of C₂H₂ occupied 22.4 L at STP.
Therefore, 3.91 moles of C₂H₂ will occupy = 3.91 × 22.4 = 87.58 L
Thus, 87.58 L of C₂H₂ is produced from the reaction.
Of the two bromoderivatives, C6H5CH(CH3)Br and C6H5CH(C6H5)Br which one is more reactive in SN1 substitution reaction and why?
Answer:
tertiary
Explanation:
tertiary halogenoalkanes are more reactive than primary and secondary as the carbocation is more stable due to alkyl groups( have high electron density) donating electrons to stabilise the carbocation
Which ions aren't shown in net ionic reactions, because they are present as both reactants and products of the reaction, so they do not participate in the reaction?
Explanation:
This is correct!
Ions that exist in both the reactant and product side of the equation are referred to as spectator ions. Overall, they do not partake in the reaction. If they are present on both sides of the equation, you can cancel them out.
An example is;
Na+(aq) + Cl−(aq) + Ag+(aq) + NO3−(aq) → Na+(aq) + NO3−(aq) + AgCl(s)
The ions; Na+, NO3−(aq) would be cancelled out to give;
Cl−(aq) + Ag+(aq) → AgCl(s)
name two solid liquid and gaseous element at the normal temperature and normal press
ure
Answer:
Solid: calcium and potassium
Liquid: mercury and bromine
Gaseous: oxygen and fluorine
Explanation:
Matter exists in three different states namely: solid, gaseous and liquid. Elements that are found in nature are classified as matter. Since, these elements are grouped as matter, they can either be found as either solids, liquids or gases at normal temperature and pressure.
At normal temperature (20°C or 293K) and pressure (1 atm), the following elements are found to exists in the respective state of matter:
Solid: Calcium (Ca) and potassium (K)
Liquid: Mercury (Hg) and bromine (Br)
Gaseous: Oxygen (O) and fluorine (F)
3 A 60.00 g sample of tetraethyl lead, a gasoline additive, is found to contain 38.43 g lead, 17.83 g carbon, and 3.74 g hydrogen. Find its empirical formula.
Answer:
The empirical formula is PbC₈H₂₀
Explanation:
To determine the empyrical formula, we need to determine the % of each element:
(38.43g / 60 g ). 100 = 64.05 % of Lead
(17.83 g / 60 g) . 100 = 29.72 % of Carbon
(3.74 g / 60 g) . 100 = 6.23 % of H
Now we divide by the atomic mass:
64.05 / 207.2 = 0.309
29.72 / 12 = 2.48
6.23 / 1 = 6.23
We pick the lowest value and we divide again, with this number
0.309 / 0.309 = 1 Pb
2.48 / 0.309 = 8 C
6.23 / 0.309 = 20 H
PbC₈H₂₀
When a mixture of oxygen and hydrogen is ignited in a test tube, the reaction shown occurs. Hydrogen + Oxygen → Water + Energy Substances that form as a result of a chemical reaction are called catalysts catalysts products products precipitates precipitates reactants
Answer:
products
Explanation:
In chemistry, chemical reactions is the combination of two or more substances to yield other substances. The substances that react is called REACTANTS while the substances formed after the reaction is called PRODUCTS.
According to this question, a mixture of oxygen and hydrogen is ignited in a test tube as follows:
Hydrogen + Oxygen → Water + Energy
In this reaction, the substances being combined (usually found on the left side of the equation) are hydrogen and oxygen. Hence, oxygen and hydrogen are REACTANTS. Also, the substances produced as a result of the reaction is water (H2O). The PRODUCTS of the reaction is WATER.
Answer:
Soy isk polq ja uso??
Explanation:
Na uend qoaki uwsh.. aju qah!
Do bases lose or gain hydrogen ions?
Help :-)
Answer:
Acids are classified in the Bronsted Lowry acid-base theory as species, which losses hydrogen ions (H+, known as protons) in a chemical reaction (and are foundation species that accept hydrogen ions).
please help me ill give brainliest if right
Answer:
3000kg
Explanation:
Given parameters:
Speed = 20m/s
Kinetic energy = 600000J
Unknown:
Mass = ?
Solution:
Kinetic energy is the energy due to the motion of a body.
It is expressed as;
K.E = [tex]\frac{1}{2}[/tex] m v²
m is the mass
v is the speed
Now find m;
600000 = [tex]\frac{1}{2}[/tex] x m x 20²
600000 = 200m
m = 3000kg
Why is the organization of the periodic table by physical properties not very useful?
Answer:
It shows no regular pattern
Explanation:
Physical properties of an element are those we can observe and feel with our senses. Also, the use special equipment can enhance our perception of these properties.
The same physical property can be shared different number elements. On the periodic table, all the elements in group 1 and 2 are metals. This is not very useful for scientists whose emphasis is to distinguish one atom from the other. Therefore, physical properties are highly limited in the organization of the periodic table.Pb(SO4)2 + 4 LiNO3 → Pb(NO3)4 + 2 Li2SO4
If 2.25 moles of lead (II) sulfate are combined with 9.62 moles of lithium nitrate, how moles of lithium sulfate can be created? please help
Answer:
4.5 moles of lithium sulfate are produced.
Explanation:
Given data:
Number of moles of lead sulfate = 2.25 mol
Number of moles of lithium nitrate = 9.62 mol
Number of moles of lithium sulfate = ?
Solution:
Chemical equation:
Pb(SO₄)₂ + 4LiNO₃ → Pb(NO₃)₄ + 2Li₂SO₄
Now we will compare the moles of lithium sulfate with lead sulfate and lithium nitrate.
Pb(SO₄)₂ : Li₂SO₄
1 : 2
2.25 : 2/1×2.25 = 4.5 mol
LiNO₃ : Li₂SO₄
4 : 2
9.62 : 2/4×9.62 = 4.81 mol
Pb(SO₄)₂ produces less number of moles of Li₂SO₄ thus it will act as limiting reactant and limit the yield of Li₂SO₄.
Which of the following families would have the highest electronegativity
alkali metals
halogens
transition metals
nitrogen group
Answer:
halogens
Explanation:
Electronegativity increases as you move to the right and up the periodic table. Thus, halogens would have the greatest electronegativity.
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Can someone please solve this with the working and explanation
Answer:
A
Explanation:
As you add a bulky group to the end of a carbon chain the boiling point goes up on the molecule.
For the hydrolysis of methyl acetate express the rate of reaction in terms of different reactants and products
Answer:
See explanation
Explanation:
The equation of the reaction is;
CH3COOCH3 + H2O -------> CH3COOH + CH3OH
Now recall that the rate of reaction refers to the rate of disappearance of reactants or the rate of appearance of products. We indicate that reactants disappear by a negative sign placed in front of the concentration term of reactants.
Rate = k -d[CH3COOCH3]/dt
Rate = k d[CH3COOH]/dt
Rate = k d[CH3OH]/dt
Note; i did not write the rate in terms of water because it is a solvent that is present in large excess. Its concentration does not change with time.
Why do helium balloons pop in a hot car?
Answer: because helium molecules get bigger when they heat up, so if your balloons keep getting hotter, they will eventually pop.
Explanation:hope these gave u a clue and have a wonderful Christmas break ❄️
Explanation:
Because helium molecules grow bigger as they are heated up and eventually they popped out
PLEASE HELP
The area in which you live has a particular climate. It also has weather. Which claim describes the difference between climate and weather?
Group of answer choices
Weather is determined by temperature and precipitation, whereas climate is determined only by humidity, air pressure, and wind conditions.
Climate is the condition of Earth’s atmosphere at a particular time and place, whereas weather is the characteristic climate in an area over a long period of time.
Climate is determined by temperature and precipitation, whereas weather is determined only by humidity, air pressure, and wind conditions.
Weather is the condition of Earth’s atmosphere at a particular time and place, whereas climate is the characteristic weather in an area over a long period of time.
Answer:
Weather is the condition of Earth’s atmosphere at a particular time and place, whereas climate is the characteristic weather in an area over a long period of time.
Explanation:
Weather and climate are two very important conditions that describes the atmospheric overview of a place.
Weather is reported over a short period of time, it is the condition of the atmosphere at a particular time and place.
Climate is reported over a long period of term. The average weather condition of a place over a long period of time is the climate.
The most important control over the climate of a place is the temperature and amount of precipitation it receives over a period of time. Weather conditions is reported using more diverse factors such a temperature, pressure, humidity, precipitation, etc.Do acids lose or gain hydrogen ions?
Help
please
Answer: They lose them :)
Explanation:
solid to liquid change melting
Answer:
The process of a solid becoming a liquid is called melting. (an older term that you may see sometimes is fusion). The opposite process, a liquid becoming a solid, is called solidification. For any pure substance, the temperature at which melting occurs—known as the melting point—is a characteristic of that substance.
Hope this helps, have a wonderful day/night, stay safe, happy holidays, and merry christmas!
Show, in a step by step fashion, your calculations to determine the percent
by volume of a solution that is made by mixing 50 ml of ethanol with 210
ml of water.
The percent by volume of a solution : 19.23%
Further explanationGiven
50 ml of ethanol
210 ml of water
Required
The percent by volume of a solution
Solution
Percent Volume (% v/v) : volume (ml) of solute/100 ml of solution ⇒ ratio of the volume of the solute to total volume of the solution
[tex]\tt \%solute(v/v)=\dfrac{solute~volume}{solution~volume}\times 100\%[/tex]
solute= Ethanol
solvent=water
Solution = solute+solvent
Total volume of the solution :
[tex]\tt =volume~of~Ethanol+solume~of~water\\\\=50~ml+210~ml\\\\=260~ml[/tex]
Percent by volume :
[tex]\tt \%volume=\dfrac{50}{260}\times 100\%\\\\\%volume=19.23\%[/tex]