Answer:
1869, the Russian chemist Dmitri Mendeleev came to prominence with his tabular ... He found that few of the new developments in the field of chemistry had made ... He corrected the known atomic masses of some elements and he used the ... Atomic number 101, Mendelevium, is named after the periodic table's architect
Explanation:
1869, the Russian chemist Dmitri Mendeleev came to prominence with his tabular ... He found that few of the new developments in the field of chemistry had made ... He corrected the known atomic masses of some elements and he used the ... Atomic number 101, Mendelevium, is named after the periodic table's architect
Can someone help me and explain why they got what they got?
Answer:
24.32 amu
Explanation:
From the question given above, the following data were obtained:
Isotope A (Mg–24):
Mass of A = 24 amu
Abundance (A%) = 79%
Isotope B (Mg–25):
Mass of B = 25 amu
Abundance (B%) = 10%
Isotope C (Mg–26):
Mass of C = 26 amu
Abundance (C%) = 11%
Average atomic mass of Mg =?
Average atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]
= [(24 × 79)/100] + [(25 × 10)/100] + [(26 × 11)/100]
= 18.96 + 2.5 + 2.86
= 24.32 amu
Thus, the average atomic mass of Mg is 24.32 amu
Volume and mass examples
Answer: Example: A bowling ball and a basketball are about the same volume as each other, but the bowling ball has much more mass
Explanation: Mass and volume are two units used to measure objects. Mass is the amount of matter an object contains, while volume is how much space it takes up.
Chemistry problem. please help
Answer:
solid X contains only ionic bond, and solid Y contains only covalent bonds.
Explanation:
solid X contains only ionic bond, and solid Y contains only covalent bonds. Because ionic compounds they have high melting point compared to covalent compounds, ionic compound they are generally insoluble in non polar solvent such as toluene but soluble in polar solvent such as water, ionic compound they conduct electricity.
The concentration of KBr in a solution prepared by dissolving 2.21g of KBr in 897 g of water is __________ m.
A) 2.46.
B) 0.0167.
C) 2.07 x 10-5.
D) 0.0186.
E) 0.0207.
Answer:
E) 0.0207
Explanation:
The molal concentration, m, is defined as the ratio between moles of solute (In this case, KBr) per kg of solvent (water):
Moles KBr -Molar mass: 119g/mol-
2.21g KBr * (1mol / 119g) = 0.01857moles
Mass solvent:
897g * (1kg / 1000g) = 0.897kg
Molal concentration:
0.01857 moles / 0.897kg =
0.0207m
Right solution is:
E) 0.0207.Which of the choices below is matter? *
electricity
wood
sound
O
fire
Answer:
Wood
Explanation:
Matter is anything that has mass. Nor sound, fire or electricity have mass which leaves wood as the final answer.
Please help with the chart
Answer:
no
Explanation:
A sample of gas occupies a volume of 350.0 mL at 840mm Hg and 33°C. Determine the volume of this sample at 600 mm By and 52°C
Answer:
V₂ = 520.42 mL
Explanation:
Given data:
Initial volume = 350.0 mL
Initial pressure = 840 mmHg
Initial temperature = 33°C (33 +273 = 306 K)
Final temperature = 52°C (52+273 = 325 K)
Final volume = ?
Final pressure = 600 mmHg
Formula:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
Solution:
V₂ = P₁V₁ T₂/ T₁ P₂
V₂ = 840 mmHg × 350.0 mL × 325 K / 306 K × 600 mmHg
V₂ = 95550000 mmHg.mL.K /183600 K.mmHg
V₂ = 520.42 mL
What is the tissue that allows for flexibility of bones?
Answer:
Bone Marrow, or Cartilage
You take a balloon with fixed volume and submerge it in a hot tub for a few minutes. What would you expect to happen to the pressure of the balloon after you take it out? Explain.
Answer:
pressure will be high because the temp is high, the gas is gonna expand
Explanation:
when temp increases it causes gas to expand which causes high pressure. this is because pv=nrt, p=pressure in atmosphere, v is volume in liters, n is number of particles in moles, t is temp in kelvin is r is ideal gas constant
The impact on the pressure should be high since the temperature should be high due to which the gas should be expanded.
What is pressure?Pressure refer to the force applied that should be perpendicular to the surface of an object per unit area so that the force is distributed. In the case when the temperature should be increased so here gas should be expanded that resulted into the high temperature.
Here the following formula should be applied
pv = nrt
Here p = pressure
v means the volume
n means no of particles in moles
r means the ideal gas constant
learn more about pressure here: https://brainly.com/question/4417455
The half-life of the radioisotope 158Eu is 0.77 h. How much time is required for a 160.0-g sample of 158Eu to decay to 2.07 g?
a. 3.0 h
b. 4.0 h
c. 6.0 h
d. 2.1 h
e. 4.8 h
Answer: e. 4.8 h
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for rate constant
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{0.77hr}=0.9hr^{-1}[/tex]
b) for 160.0 g to decay to 2.07 g
[tex]t=\frac{2.303}{0.9}\log\frac{160.0}{2.07}[/tex]
[tex]t=4.8hr[/tex]
The time required for a 160.0-g sample of 158Eu to decay to 2.07 g is 4.8 hours
Please answer. Thank you
Answer:
Explanation:
what are tho anwser choices
What is a solute?
A material that is dissolved in another material.
O A material in which another material is dissolved.
An area of space surrounding the nucleus.
O Chemical formulas on the left side of an equation.
As the number of bonds increases, the strength of the bond ________.
Answer:
increases
Explanation:
What is a mixture?
any substance with a uniform composition
a combination of pure substances bonded chemically
any group of elements that are chemically bonded to one another
a blend of any two or more kinds of matter where each maintains its own unique
properties
Which term describes a mixture that is not uniform through
What is the molarity of a 5mol solution in 3L?
Answer:
1.67 M.
Explanation:
M = mol/L ⇒ M = 5mol / 3L = 1.67 M
How much excess reactant remains from the reaction of 8.3g of sodium and 4.5g of chlorine?
a. 8.2g Na
b. 5.4g Na
c. 5.4g Cl2
d. 8.2g Cl2
Answer:
5.4 g Na
Explanation:
Calculate the mass of sodium chloride from both reactants. The lesser value is the amount is the theoretical yield. Subtract the mass of the calculated mass of sodium chloride from the mass of the reactants.
A student mixes 50.0 mL of 1.00 M Ba(OH)2 with 83.5 mL of 0.475 M H2SO4. Calculate the mass of BaSO4 formed.
Answer:
9.26g of BaSO₄ are formed
Explanation:
The reaction of Ba(OH)₂ with H₂SO₄ is:
Ba(OH)₂ + H₂SO₄ → BaSO₄ + 2H₂O.
To solve this question we need to determine the moles of each reactant in order to find the limitng reactant. With the moles of limiting reactant we can find the theoretical moles of BaSO₄ produced and its mass, as follows:
Moles Ba(OH)₂:
50.0mL = 0.050L * (1.00mol / L) = 0.0500moles
Moles H₂SO₄:
83.5mL = 0.0835L * (0.475mol / L) = 0.0397moles
That means limiting reactant is H₂SO₄.
Based on the reaction, 1 mole of H₂SO₄ produce 1 mole of BaSO₄. The theoretical moles of BaSO₄ produced are 0.0397 moles.
The mass is (Molar mass BaSO₄: 233.38g/mol):
0.0397 moles BaSO₄ * (233.38g / mol) =
9.26g of BaSO₄ are formedPlease help me please!!
(Picture above)
Answer:
I'll tell you how to find it, but no answers
Explanation:
It's pretty simple. Your north and south points go first, then your east and west. You look at the dot, and trace your finger down the two lines to get your lattitude and longitude. From there, you just write it out. For example, G would be at (0,0) because the lines match up at 0,0 where the point is.
Does your heart desire my love and affection?
Yes, your heart does because everyone loves me, since I am well known as Kirby. ♥
True or False: Cohesion is the attraction between particles of the same
substance
Answer: True
Explanation:
Need help fast please 15 points!!!
Which changes of matter can steam undergo?
A. condensation and sublimation
B. condensation and freezing
C. disposition and condensation
Answer:
C. disposition and condensation
Explanation:
Suggest a possible mechanism for the acid catalyzed reaction of a typical ketohexose to give 5-hydroxymethylfurfural.
Answer:
See explanation
Explanation:
Taking the acid catalysed hydrolysis of fructose C6H12O6, the mechanism begins with the protonation of an -OH group as shown.
This is now followed by dehydration and formation of a keto-enol tautomer. The keto form is now dehydrated followed by the protonation of a second -OH group.
A second dehydration followed by deprotonation leads to the formation of 5-hydroxymethylfurfural.
Image credit: SciElo
Rocks melt at what temperature range? a. 50 to 100 degrees Celsius b. 130 to 200 degrees Celsius c. 220 to 500 degrees Celsius d. 600 to 1,300 degrees Celsius
600 and 1,300 degrees Celsius
In pretty sure
If the resistance of a circuit is 3 ohms, and the voltage produced by the cell in the circuit is 12 volts, what's the magnitude of the current?
Answer:
4 AExplanation:
The magnitude of the current can be found by using the formula
[tex]i = \frac{v}{r} \\ [/tex]
v is the voltage
r is the resistance
From the question we have
[tex]i = \frac{12}{3} = 4 \\ [/tex]
We have the final answer as
4 AHope this helps you
Answer:
4A
Explanation:
What can you say about the pH before and after the last drop of HNO3 was added?
Answer:
the water symbol i forgot tho
Explanation:
hi
NaOH is a base. Therefore, the pH is initially very high and above 7. If you add HNO3, which is a strong acid and has a pH less than 7, you will lower the pH of the solution. In fact, at the equivalent curve, you will have a pH of 7 because you are mixing a strong acid and strong base. Depending on how much HNO3 is added, the pH will continue to go down.
A compound is an example of pure substance
True
False
When forming an ion, nitrogen will have what charge?
Answer:
The valence electrons of nitrogen in its compounds are all sp³ hybridized orbitals. The formal charge on N is usually -1 for an anion, 0 for a neutral compound, and +1 in cations. A nitrogen atom with a formal charge of -3 would correspond to a nitride ion, N³⁻, which is strongly basic in aqueous solution. Hope this helps...
Explanation:
Brainliest please?
Why is a “spark” of energy required to begin the chemical reaction of burning a fossil fuel? What is another name for this spark of energy?
Answer: a burst
Explanation: a burst of energy could be substatuded for spark of energy
A spark of energy is required to begin the chemical reaction of burning a fossil fuel because; This spark of energy is required to attain the activation energy of the reaction.
Another name for this spark of energy is Ignition.
Definition:
The activation energy of a chemical reaction is the minimum amount of energy required for the commencement of the chemical reaction.
In this case, the spark of energy is required to attain the activation energy of the reaction.
Read more:
https://brainly.com/question/7639475
An aqueous solution of calcium hydroxide is standardized by titration with a 0.112 M solution of hydrobromic acid. If 15.2 mL of base are required to neutralize 12.4 mL of the acid, what is the molarity of the calcium hydroxide solution?
Answer:
0.0457 M
Explanation:
The reaction that takes place is:
2HBr + Ca(OH)₂ → CaBr₂ + 2H₂OFirst we calculate how many moles of acid reacted, using the HBr solution's concentration and volume:
Molarity = Moles / VolumeMolarity * Volume = Moles0.112 M * 12.4 mL = 1.389 mmol HBrNow we convert HBr moles to Ca(OH)₂ moles, using the stoichiometric ratio:
1.389 mmol HBr * [tex]\frac{1mmolCa(OH)_{2}}{2mmolHBr}[/tex] = 0.6944 mmol Ca(OH)₂Finally we calculate the molarity of the Ca(OH)₂ solution, using the given volume and calculated moles:
0.6944 mmol Ca(OH)₂ / 15.2 mL = 0.0457 MWhat makes an object cool down?
A) adding cold molecules
B) subtracting heat molecules
C) increasing the kinetic energy of the molecules
D) Decreasing the kinetic energy of the molecules
Answer:
D) decreasing the kinetic energy of the molecules
Explanation:
