Answer:
c cells
Explanation:
learned that in 7th grade
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:
Please answer. Thank you
Answer:
Explanation:
what are tho anwser choices
True or False: Cohesion is the attraction between particles of the same
substance
Answer: True
Explanation:
Which is an example of a compound? * He3 or H2O or C
Answer:
H2O
Explanation:
There is more than one element
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
As the number of bonds increases, the strength of the bond ________.
Answer:
increases
Explanation:
What is the frequency of visible light which has a wavelength of 625nm?
Answer:
The answer is 4.80 x 1014s-1b
Explanation:
625 nm x 10-9m= 6.25 x 10-7 m = c = 2.998 x 108m/s1 nm 6.25 x 10-7m=4.80 x 1014s-1b.)
The frequency of visible light is equal to 4.8 ×10¹⁴s⁻¹.
What are frequency and wavelength?Frequency can be described as the number of oscillations of a wave in a time of one second. The frequency of the wave or light has S.I. units which are per second (s⁻¹) or hertz.
Wavelength can be defined as the distance between the two adjacent points of a wave in the phase with each other. Two adjacent crests or adjacents troughs on a wave are separated by a distance is called wavelength.
The relationship between the speed of light, frequency, and wavelength is:
c = νλ
Given, the wavelength of the light, λ = 625nm = 625 × 10⁻⁹ m
Then we know that the speed of light, c = 3 × 10⁸ ms⁻¹
The frequency of the light can be calculated from the above-mentioned equation:
The frequency of the given visible light will be equal to:
ν = c/λ = 3× 10⁸ ms⁻¹/625 × 10⁻⁹ m = 4.8 ×10¹⁴ Hz
Therefore, the frequency of visible light is equal to 4.8 ×10¹⁴ Hz.
Learn more about wavelength and frequency, here:
brainly.com/question/18651058
#SPJ2
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.
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?
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
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.Please help with the chart
Answer:
no
Explanation:
Please help!! On a timer!! If you can help me with any of the following questions please, I'm lost.
1. What is the density of a block of marble that occupies 251 cm^3 and has a mass of 933 g? Answer in units of g/cm^3
2. Lee pushes horizontally with a force of 45 N on an 18 kg mass for 12 across the floor. Calculate the amount of Lee did. Answer in units of J.
3. What is the mass number of an element with atomic number 10 and 10 neutrons.
Answer:
3. Answer= Neon (Ne) is the Group 8A chemical element that has atomic number 10 and mass 20.1797.
Most elements are __ at room temperature
Answer:
Most elements are Solids at room temperature
Need help please? Thanks youu
Answer:
A
B
E
Explanation:
"Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei
and fusion is the process where two light nuclei combine together releasing vast amounts of energy"
a process that releases energy is respiration
how many molecules of nitrogen are in 1.25 mol N2?
Answer:
7.52 x 10²³ molecules N
Explanation:
multiply 1.25 mol of N2 by Avogadro's Number
Question 3 of 25
What is another name for Group 14?
Answer:
4A
Explanation:
on the periodic table
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.
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
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
Balanced or Unbalanced
K+2MgBr=KBr+Mg
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 MCan someone answer 4 for me please?
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 formedWhat is the molarity of a 5mol solution in 3L?
Answer:
1.67 M.
Explanation:
M = mol/L ⇒ M = 5mol / 3L = 1.67 M
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
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:
A compound is an example of pure substance
True
False
The density of aluminum is 2.7 g/cm3 and that of Al2O3 is about 4 g/cm3. Calculate the PB ratio for Aluminum. (Hint: The Pilling-Bedworth Ratio (PBR) gives the volume of oxide formed to the volume of metal atoms.)
a) 1.28
b) 0.28
c) 0.75
Answer:
1.28
Explanation:
Al = aluminium
Density of Al = 2.7g/cm³
Density of Al2O3 = 4g/cm³
Molecular weight of Aluminum = 27g/mol
Molecular weight of Al2O3= 101.96 g/mol
Pilling bedworth ratio = Rob
= M(Al2O3) * density of Al / n* molecular weight of Al * density of Al2O3
= 101.96g/mol x 2.7g/cm³/2x 27g/mol x 4g/cm³
= 275.292/216
= 1.28
From the calculation above 1.38nis the PB ratio for aluminum
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
