Answer:
I found on internet may be it helps
Explanation:
Here, we provide a general review of recent studies into the genetic basis of human brain evolution. The insights gleaned from these studies can be broadly divided into three categories: (i) positive selection on protein-coding regions of the genome that lead to changes in the sequences of existing proteins; (ii) duplication and deletion of genes; and (iii) evolutionary changes in non-coding regions of the genome, especially those in cis-regulatory sequences that lead to altered gene expression .
I AM GIVING BRAINLIEST! PLEASEEEEEEEEEEE HELPPPPP I NEEED HELPPPP PLEASEEEE
Find the molecular formula for a compound with-
4.04 g N, 11.46 g O, molar mass 108.0 g/mol.
? moles N =
? moles O =
N : O =
empirical formula =
molecular mass of empirical formula =
The molar mass ratio of (molecular formula/empirical formula) =
molecular formula =
Answer:
moles of N
4.04 g / 14.01 = 0.288
moles of O
11.46 / 16 = 0.72 moles
divide both of them by the lowest number of moles to get the ratio
0.288 / 0.288= 1
0.72 / 0.288 = 2.48
now multiply both by 2, to make it a whole number =
ratio = 2 : 5
empirical formula = N2O5
the molar mass of the compound = 108.01
molar mass of the empirical formula = 108.02
when you divide this to get the factor the factor is also 1, so you dont really change anything
FORMULA = N2O5
Explanation:
I had it written done from my school notes
I really hope this helps
The three most common phases of matter are
Answer:
Solid, Liquid, and Gas
Explanation:
There are constantly these three phases of matter around us every day. The water you drink is a liquid, the chair you sit on is a solid, and the air you breathe is a gas.
The conversation of cyclopropane to propene in the gas phase is a first order reaction with a rate constant of 6.7x10-⁴s-¹. a) if the initial concentration of cyclopropane was 0.25M , what is the concentration after 8.8min?b) how long (in min) will it take for the concentration of cyclopropane to decrease from 0.25M to 0.15M?
Answer: a) The concentration after 8.8min is 0.17 M
b) Time taken for the concentration of cyclopropane to decrease from 0.25M to 0.15M is 687 seconds.
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) concentration after 8.8 min:
[tex]8.8\times 60s=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{a-x}[/tex]
[tex]\log\frac{0.25}{a-x}=0.15[/tex]
[tex]\frac{0.25}{a-x}=1.41[/tex]
[tex](a-x)=0.17M[/tex]
b) for concentration to decrease from 0.25M to 0.15M
[tex]t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\log\frac{0.25}{0.15}\\\\t=\frac{2.303}{6.7\times 10^{-4}s^{-1}}\times 0.20[/tex]
[tex]t=687s[/tex]
At what temperature does the solid start meltin
-20°C
0°C
20"
80°C
Answer:
0 C.
Explanation:
Which value gives the number of particles in 1 mol of a substance?
6.02 x 1021
6.02 x 1022
6.02 x 1023
6.02 x 1024
Answer: it's C 6.02×10²³
Explanation:
I got it right in edge
hi:) why do acids produce hydrogen ions in aqueous solution?
Answer:
An acid produces hydrogen ions in aqueous solution because it reacts with the water molecules by giving a proton to them.
Explanation:
When hydrogen chloride gas dissolves in water to produce hydrochloric acid, the hydrogen chloride molecule gives a proton (a hydrogen ion) to a water molecule.
Answer:
Acids produce hydrogen ions in aqueous solution because they have a higher concentration of hydrogen ions than hydroxyl ions and that's the reason too why they have a lower pH.
Hope this helps.
Which of these is an example of interactions between the atmosphere and hydrosphere? (3 points) formation of snow cracking of rocks due to heat destruction of houses by wind uprooting of trees during tornadoes
Answer:
A. formation of snow
Explanation:
The formation of snow is an example of interactions between the atmosphere and hydrosphere.
As snow formation takes place when water vapor converted into liquid through condensation in the clouds. As water droplets rises high in clouds, cooler air present in atmosphere allow to lower the temperature and water droplets form ice or snow.
Hence, the correct option is A.
Answer:
A:formation of snow
Explanation:
Mantle material rises in convection currents because heated materials become more dense.
True Or False
Answer:
True
Explanation:
For the reaction NH4Cl (s)→NH3 (g) + HCl (g) at 25°C, ΔH = 176 kJ/moland ΔS = 0.285 kJ/(mol - K).
What is the ΔG, and will this reaction be spontaneous in the forward direction?
169 kJ/mol; no
-91 kJ/mol; yes
91 kJ/mol; no
91 kJ/mol; yes
Answer:
C: 91 kJ/mol; no
Explanation:
Just took the quiz! :)
The ΔG is 91kJ/mol and the reaction is not spontaneous in the forward direction and the correct option is option 3.
What is Gibbs free energy change?Gibbs free energy, also known as the Gibbs function, Gibbs energy, or free enthalpy, is a quantity that is used to measure the maximum amount of work done in a thermodynamic system when the temperature and pressure are kept constant.
The Gibbs free energy of the system is a state function because it is defined in terms of thermodynamic properties that are state functions.
The change in the Gibbs free energy of the system that occurs during a reaction is therefore equal to the change in the enthalpy of the system minus the change in the product of the temperature times the entropy of the system.
ΔG = ΔH - TΔS
Given,
ΔH = 176kJ/mol
ΔS = 0.285kJ/mol K
T = 25⁰C = 273 + 25 = 298K
ΔG = ΔH - TΔS
ΔG = 176000 - 298 × 285
= 91070 = 91 kJ/mol
Since ΔG is positive, the reaction is not spontaneous in the forward direction.
Therefore, the ΔG is 91kJ/mol and the reaction is not spontaneous in the forward direction and the correct option is option 3.
Learn more about Gibbs free energy change, here:
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Rice has a bulk density of 0.9 g/mL, but an individual grain of rice has a
density of 1.1 g/mL. Water has a density of 1.0 g/mL. What would happen to
a cup of rice when poured into a pot of water?
Answer:
Individual grain of rice will sink.
Explanation:
Given:
Rice bulk density = 0.9 g/ml,
Individual grain of rice density = 1.1 g/ml
Water density = 1.0 g/ml
Find:
What happens with a cup of rice when poured into water =?
Explanation:
Each piece of grains of rice will sink into the water because individual grains of rice has a higher density than water.
Steel:
Propane:
Calcium chloride:
Water:
Answer:
Steel is a metallic bond
Propane is a covalent bond
Calcium Chloride is an Ionic Bond
Water is a covalent bond
Explanation:
ence a material's properties, identify each of the , ionic, covalent, or metallic bonds
Ionic Bonds are where the extra outer electron of one atom transfers to the other atom.
Covalent Bonds are where the outer electron of one atom takes the open path to the nucleus (negative valance) of a 2nd atom.
Metallic Bonds are formed from the attraction between free electrons and fixed positively charged metallic atoms. Metallic bonds extend over the entire molecular structure.
Substance Properties
Steel Conducts electricity as solid and liquid
Propane Low melting point
Calcium Chloride Conducts electricity when dissolved in water
Water Solid form is brittle, melts at 0C
Steel is an alloy of carbon, iron and other things
Propane = C3H8 C4- H+
Calcium Chloride = CaCl2 = Ca2+ Cl-
Water = H2O = OH- and H+
Which of following is the most accurate description of a piston in an internal-
combustion engine?
A shaft that converts the up-and-down motion into a rotary motion
A plug that protrudes through the cylinder head and makes sparks that ignite the
air-and-fuel mixture
A can-shaped component that moves smoothly up and down and is the main
moving part
O A hollow metal tube drilled into the solid metal engine block
Answer:
A can-shaped component that moves smoothly up and down and is the main moving part
Explanation:
I chose the other answer that other person listed but got it wrong. This instead is the correct answer
Answer:
C. A can-shaped component that moves smoothly up and down and is the main
moving part
Explanation:
The piston is a can-shaped component that can move smoothly up and down inside the cylinder; it moves up to compress the air-and-fuel mixture and is pushed down when the spark plug ignites the mixture, which causes an explosion.
A beaker contains 41.3 mL of pentane ( C5H12 , density is 0.626 g/mL). Determine how many C atoms this liquid contains.
Answer:
41.3 mL OF PENTANE CONTAINS 62.608 *10^-27 CARBON ATOMS.
Explanation:
Volume of Pentane = 41.3 mL
Density = 0.626 g/mL
Since density is defined as mass per unit volume. Calculate the mass:
Density = mass / volume
Mass = density * volume
Mass = 0.626 g/mL * 41.3 mL
Mass = 0.015 g of pentane
Molar mass of pentane C5H12 = ( 12* 5 + 1*12) = 60 + 12 = 72 g/mol
Number of moles = mass / molar mass
Number of moles = 0.015 g / 72 g/mol
Number of moles = 2.08 * 10^-4 moles.
Since 1 mole of pentane contains 5 moles of carbon, we can then calculate how many moles of csrbon 2.08*10^-4 moles will contain
1 mole of pentane = 5 moles of carbon
2.08 *10^-4 moles = x moles
x mole = 5 * 2.08*10^-4
x mole = 10.4 *10^-4 moles of carbon
In other words, 10.4*10^-4 moles of carbon is present in 41.3 mL of pentane
We can then calculate the number of carbon atoms present in the liquid using:
From 1 mole containing 6.02 *10^-23 atoms, 10.4 *10^-4 moles of pentane will contain:
1 mole = 6.02*10^-23 atoms
10.4 *10^-4 moles = (6.02*10^-23 * 10.4 *10^-4) atoms of pentane
= 62.608 *10 ^-27 atoms of pentane.
So therefore, 41.3 mL of pentane will contain 62.608 * 10 ^-27 carbon atoms
The number of C atoms in 41.3 mL of pentane (C₅H₁₂) of density 0.626 g/mL is 2.16x10²³.
To find the number of C atoms in pentane, we need to find the number of moles.
We can calculate the mass from the density:
[tex] d = \frac{m}{V} [/tex]
Where:
d: is the density = 0.626 g/mL
V: is the volume = 41.3 mL
The mass is:
[tex] m = d*V = 0.626 g/mL*41.3 mL = 25.85 g [/tex]
Now, with the molecular weight of the pentane, we can calculate the number of moles:
[tex] \eta = \frac{m}{M} = \frac{25.85 g}{72.15 g/mol} = 0.358 \:moles [/tex]
The number of C atoms can be found with Avogadro's number:
[tex] n_{C} = \frac{6.022\cdot 10^{23} \:atoms}{1\:mol}*0.358 \:moles = 2.16 \cdot 10^{23} \:atoms [/tex]
Therefore, the liquid contains 2.16x10²³ C atoms.
Learn more here:
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I hope it helps you!
1. What is the wavelength of a photon of light with a frequency of 6.10 x 10^15 Hz?
Answer:
0.000000000000005 mm
Explanation:
why is the renewable energy resource you chose is negative?
Answer:
There’s a high need for energy storage and are very expensive. Renewable energy is also not always available because some need sun while others need wind.
Explanation:
is Naci a metal or none metel
Answer:
Salt (NaCl) is an ionic bond that consists of Sodium (Na) which is a metal with positive charge combines with Chlorine (Cl), a nonmetal with a negative charge.
Explanation:
A student is trying to dissolve 20 grams of sugar in a beaker containing 250 milliliters of water at room temperature. What can the student do to make the sugar dissolve faster in the water? a. decrease the temperature of the water b.use larger pieces c.stir rapidly d.use less water
Answer:
C. Stir rapidly
Determine the power of 900 joules of work done in 4 seconds
A) 3600 W
B) 225 W
C) 904 W
D) 450 W
Answer:
B. 225 W
Explanation:
Power is the measure of the amount of work done in a certain time frame. It can be found using the following formula.
p=w/t
where w is the amount of work done in joules and t is the amount of time in seconds.
We know that 900 joules of work was done in 4 seconds.
w=900 J
t= 4 s
Substitute these values into the formula.
p=900 J/ 4 s
Divide 900 by 4
900/4=225
p= 225 J/s
1 Joules of work per second (J/s) is equal to 1 Watt (W). Therefore, we can substitute Watts for Joules per second.
p= 225 Watts
The power is 225 Watts, and the correct answer is B.
What is the molarity of a NaCl solution with 3.7 moles and 2.3 L?*
Answer:
5.0 molatrity
Explanation:
because i just known
Answer:
Approximately 1.61
Explanation:
Molarity = Moles/Liters
Molariry = 3.7 moles NaCl / 2.3L
Molariry = 1.61
An electron is in a region outside the nucleus. An electron
a) Is larger than a proton and has no charge
b) Has less mass than a proton and has a negative charge
c) Is smaller than a proton and has no charge
d) Has a positive charge
Answer:
b
Explanation:
electrons lie in the orbits of the atom. they are negatively charged and they are very small in size. they have very less mass than proton. ele tron has 1/1840 mass of proton.
Ammonia (NH3) Is base.
How best do you describe Ammonia when dissolved in water
B. Ammonia forms a neutral solution.
C. Ammonia forms a buffered solution.
d. Ammonia acts as base because has OH- and makes water accepts hydrogen.
Answer:
Ammonia accepts a proton from water
Explanation:
Let us quickly remind ourselves of the Brownstead-Lowry definition of an acid. According to Brownstd-Lowry, an acid is any substance that donates hydrogen ions while a base is any substance that accepts hydrogen ions. The hydrogen ion is also known as a proton.
If we look at the behaviour of ammonia in water;
NH3(g) + H2O(l) ----> NH4^+(aq) + OH^-(aq)
We can easily see that ammonia accepts a proton from water (this makes it a Brownstd-Lowry base) and the hydroxide ion is formed in the process. Water functions as the proton donor here.
What’s one renewable energy resource that can be used instead of fossil fuels ?
Answer:
Solar Energy & Wind Energy
Explanation:
These are renewable energy and can be used used in replacement for fossil fuels.
PLS MARK ME AS BRAINLIEST!!
Balance the combustion reaction between propane and oxygen.
C ₃ H ₈+ O ₂→ CO ₂ + H ₂ O
Answer:
The answer is C3H8 + 5O2 → 3CO2 + 4H2O .
Answer:
[tex]\huge \boxed{\mathrm{C_3 H_8 +5O_2 \Rightarrow 3CO_2 +4 H_2 O}}[/tex]
[tex]\rule[225]{225}{2}[/tex]
Explanation:
[tex]\sf C_3 H_8 +O_2 \Rightarrow CO_2 + H_2 O[/tex]
Balancing Carbon atoms on the right side,
[tex]\sf C_3 H_8 +O_2 \Rightarrow 3CO_2 + H_2 O[/tex]
Balancing Hydrogen atoms on the right side,
[tex]\sf C_3 H_8 +O_2 \Rightarrow 3CO_2 +4 H_2 O[/tex]
Balancing Oxygen atoms on the left side,
[tex]\sf C_3 H_8 +5O_2 \Rightarrow 3CO_2 +4 H_2 O[/tex]
[tex]\rule[225]{225}{2}[/tex]
what are two factors about particles that enable them to form solutions (SCIENCE)
Answer:
temperature and whether or not they are polar or non-polar.
review the types of elements that create ionic bonds as
well as the types of elements that create covalent bonds.
• N2 • CCl4 • SiO2
• AlCl3 • CaCl2 • LiBr
Answer:
N2 Covalent
CCl4 Covalent
SiO2 Covalent
AlCl3 Covalent
CaCl2 Ionic
LiBr Covalent
Explanation:
With covalent bonds, there is a sharing of electron pairs between the atoms.
With ionic bonds, there is complete transfer of valence electrons between atoms. Formed by the interaction of a metal with a non-metal.
Where:
Electrons aren't transferred in covalent bonds.
Protons aren't transferred in covalent bonds
Protons aren't shared in covalent bonds
N3-
C4+
Cl-
Si4+ = Metal
O2- = Non-metal
Al3+ = Metal
Li+ = Metal
Ca2+ = Metal
Br 1-, 1+, 5+ = Halogen
N2 = N3- and N3- Covalent
CCl4 = C4+ and Cl- x4 Covalent
SiO2 = Si4+ and O2- x 2 Metal with non metal Covalent
AlCl3 = Al3+ and Cl- x 3 Covalent Though this one is complex as to why because it seems like it should be ionic
CaCl2 = Ca2+ and Cl- x 2 Metal with non-metal Ionic
LiBr = Li+ and Br- Covalent as neither is a non-metal
what happens to the zebra molecules once they are eaten by the cheetah?
Answer:
All living organisms need food for their body metabolism. Food helps in the provision of basic nutrients for the body’s survival and growth.
When the Cheetah eats the Zebra, enzymes acts on the Zebra molecules and converts it into smaller molecules.
The smaller molecules broken down are then readily absorbed and used by the cells of the Cheetah.
When there is unequal sharing between two atoms of the electrons in a bond, which
type of bond is it?
Answer:
polar covalent bond
Explanation:
Balance the following chemical
equation by providing the correct
coefficients.
_FeBr3 +_Na2S -> _Fe2S3 + _NaBr
Answer:
2FeBr3 + 3Na2S ➡️ Fe2S3 + 6NaBr
Where do you think trees get the nutrients they need to grow?
I
The government described in the passage most reflects the features of which type of democracy? No
The correct answer is B. Direct democracy
Explanation:
In a direct democracy, the citizens have a direct influence on government including laws, this means political decisions are made based on the opinion of citizens. This form of government differs from indirect democracy because in indirect democracy citizens only vote to choose representatives but do not participate directly in each political decision. The example presented is an example of direct democracy because even if some are not considered citizens, those who have the quality of "citizens" directly participate in the political decisions.
