Answer:One way to compare the variability of two populations is to use the pooled variance, which is a weighted average of the two sample variances.
Explanation:The pooled variance is denoted by s2p and it is calculated as follows:
s2p = [(n1 - 1)s12 + (n2 - 1)s22] / (n1 + n2 - 2)
where n1 and n2 are the sample sizes and s12 and s22 are the sample variances. The pooled variance is the average of the two sample variances when the two populations have the same variance and the two sample sizes are equal. In other words, s2p = (s12 + s22) / 2 when σ12 = σ22 and n1 = n2. This is one condition under which s2p is the average of the two sample variances.
Describe the modern system of classification. Help please!
Answer:
its called TAXON0MY
Explanation:
they are classified in eight steps namely doma!n, k!ngdom, phylum, class, order, family, genus, and spec!es
but sometimes we do not include doma!n
if you want to name an organism you use both the genus group and the spec!es group
Example:
The scientific name for humans like us is h0m0 sap!ens
H0m0- This is our genus group
sap!ens- This is our spec!es group
sorry for using the exclamation mark it means i
Answer:
The modern system of classification is a hierarchy with eight levels. These levels are domain, kingdom, phylum, class, order, family, genus, and species. There are three domains and six kingdoms in the modern system.
Explanation:
dilute hydrochloric acid+zinc metal
Explanation:
2HCl+2Zn----> 2ZnCl+H2
Explanation:
HCL + Zn= zncl2 + H2
plz mark my answer as brainlist if you find it useful.
ssignment Vhat challenges would have existed in the spread of Christianity. pe overcome. Remember social media and cell phones did not exis R < previous
Answer:
A lot of people rejected it outright. Christians were persecuted and killed for their beliefs, and there were no cars, etc for easy transportation. Most people had to walk everywhere since horses and the like were only for the rich and royal. Hope this helps, please give me brainliest :)
Explanation:
Answer: Your not the best a spelling...
Explanation:
What is the formula for triboron silicide?
Answer:
B₃Si
Explanation:
Let's take break it down. From triboron silicide;
Tri - Three
Triboron - Three boron atoms
Silicide - Silicon (with an -ide suffix)
The formular is given as;
B₃Si
Which of these is incorrect
Answer:
B
Explanation:
Ne has 10 electrons.
so the first shell will takes 2 (10-2=8)
the second shell will take 8 (8-8=0)
Metal x combines with fluorine to form XF2. what compound does it form with the sulfate ion?
A. XSO4
B. X2SO4
C.X(SO4)2
Explanation:
The answer is A b/c
the polyatomic SO4² have 2 valance electron,also
the metal X also have 2 valance electron so,They cancel each other
I need some help with with question:
How could you prepare 100 ml of a 0.40 mol/L of MgSO4 solution from a stock solution of 2.0 mol/L MgSO4. And then how would u prepare it?
Answer:
C1V1=C2V2
C1 is 2.0mol/l
V1=?
C2=.4mol/L
V2=100ml or for this 0.1L
V1 is 20ml
Best way to prepare this is to measure out 20ml of the 2 molar solution and add 80mL to it to get to 100mL
Explanation:
A scientist is comparing 2 samples of the same compound. One is pure and the other is impure. The compound is a solid at room temperature. Explain how the scientist could tell which is the pure compound. [2]
Answer:
A glass of mineral water is not pure water.
Explanation:
Pure chemical substances
Pouring water into a glass from a bottle
Food and drink may be advertised as ‘pure’. For example, you may see cartons of ‘pure orange juice’ or ‘pure mineral water’. This means that nothing else was added to the orange juice or mineral water during manufacture. However, these substances are not pure to a scientist. In science, a pure substance contains only one element or compound.
Mineral water is mostly water, but there are other substances mixed with it. These are the ingredients that you see listed on the bottle’s label.
The transfer of ____________ is achieved when eating and feeding exists
Answer:
the transfer of energy because eating is gaining energy from a source, so the energy from that source is being transfer to the animal.
The transfer of energy is achieved when eating and feeding exists. Chemical processes may emit or absorb chemical energy.
What is energy?The ability of a physical process to carry out work is known as energy. It's crucial to remember that simply because energy exists doesn't indicate that it is always ready to do tasks. Thermal energy, sometimes known as heat, is generated when atoms or molecules move. It may be thought of as temperature-related energy.
This energy results from the location of an item. For instance, a ball resting on a table possesses potential energy in relation to the ground because of the influence of gravity. Chemical processes may emit or absorb chemical energy. It is created by atoms and molecules establishing or breaking chemical bonds.
Therefore, the transfer energy is achieved when eating and feeding exists.
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A gas has a volume of 500cm3 when a pressure of 100,00N is exacted on it what will be it's volume if the pressure is changed to 150mm mecury at same temperature
Answer:
See explanation below
Explanation:
At first sight, it seems that the innitial pressure of 100,00 N would be 100,00 N/m² because pressure does not have units of newton alone. If this is true, then the calculations are the following (If it's not, but it's actually mm Hg, then skip the part of the conversion, and just do the procedure of solving for the volume).
The innitial pressure is 100 N/m² or simply 100 Pa. As the second pressure is in mm Hg, let's convert the Pascal units to mm Hg:
1 Pa -----> 0.007501 mm Hg
100 ---------> X
X = 100 * 0.007501 / 1 = 0.7501 mmHg
Now that we have the innitial pressure in mm Hg, and the temperature remains constant, we use the Boyle's law to solve for this:
P₁V₁ = P₂V₂
V₂ = P₁V₁ / P₂
Using this expression, let's solve for V₂:
V₂ = 0.7501 *¨500 / 150
V₂ = 2.5 cm³
Now, it's the innitial pressure is 100 mm Hg then the volume:
V₂ = 100 * 500 / 150
V₂ = 333.33 cm³
Check the units of the innitial pressure, one of these results should be the correct answer. If it's not, then please post again the question with the correct units.
Hope this helps
the ____metals are in the first column. each of them has full shells, plus one extra electron sitting in a new, outer shell
A) Alkali
B) Alkali Earth
C) Arthropod
Answer:
The answer is A.
Explanation:
In periodic table, group 1 (1st column) are Alkali metals and group 2 (2nd column) are Alkali Earth metals.
What is the volume of 104 g of ethine under normal conditions?
0.143 moles is the volume of 104 g of ethine under normal conditions
Which of the following statements is the best example of an interaction between the atmosphere and the hydrosphere ? Done rnnnn
how many atoms are in each compound ?
Which process directly moves nutrients from animals to the air?
D.Breathing
Oxygen obtained through respiration is used by cells in the cellular respiration process to obtain energy. Each animal has a different way of performing gas exchange, but we can say that it is through breathing that all animals move nutrients directly into the air through breathing
PLEASE HELP!!!
How many kilograms of chlorine gas is needed to produce 45.0 grams of hydrochloric acid?
Answer:
43.76 g = 0.04376 Kg
Explanation:
The equation of the reaction is given as;
H2 + Cl2 --> 2HCl
From the equation;
1 mol of Cl2 produces 2 mol of HCl
Converting to mass;
Mass = Number of mol * Molar mass
Cl2;
Mass = 1 mol * 70.906 g/mol = 70.906 g
HCl;
Mass = 2 mol * 36.458 g/mol = 72.916 g
This means;
70.906 g of Cl2 produces 72.916 g of HCl
x g of Cl2 would produce 45g of HCl
70.906 = 72.916
x = 45
x = 45 * 70.906 / 72.916
x = 43.76g
First question and I'm already stuck. Help pls!
Answer:
definite volume. indefinite shape
Answer:
Red
Explanation:
Definite volume, indefinite shape
What are some genaral properties of gases that govern their behavior
Answer:
1. Gases may be compressed
2. Gases expand when less pressure is applied.
3. Gases can be mixed.
4. Gases exert a constant pressure on its container walls.
5. Gases have low densities.
Chlorine reacts very violently. What about its electron shells makes this the case?
Answer:
it readily gains another electron. the outer electron shell is closer to the nucleus, than iodine for example, which makes it less shielded (greater attraction for another electron = violent reaction to get it)
Explanation:
the speed of sounds depend on
Answer:
medium in which it is traveling
Explanation:
i hope it helps u
What properties do atoms of the same element share? Select all that apply
atomic number
chemical reactivity
melting point
Answer: your answer is A
Explanation: the atoms has the same properties of the same element as the atomic number.
what's the correct answer? brainliest
Answer:
Explanation:accurate but not precise
Elements and compounds are usually more dense in their solid than in their
liquid state. However, water is one of the notable exceptions. The density
of ice is 0.917 g/mL, while the density of liquid water is 1.00 g/mL. What
natural phenomena does this explain?
Explanation:
The molecules in water is more tightly packed than in ice, so water has greater density than ice.
please someone help it’s due today(I will give brainliest)
Answer:
physical or chemical
boiling point
brittleness
opacity
color
density
ductility
shape
hardness
lustre
malleability
melting point
smell
solubility
state of matter
taste
texture
viscosity
Explanation:
what is the formula for P₃O₅?
Answer:
i hope its help you
Explanation:
and goodnight,goodevening,goodmorning
Are physical characteristics of an organism not genetically passed down?
In an ecosystem, the physical characteristics of an organism are genetically passed down from one generation to another.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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A) lizard
B) salamander
C) mouse
D) pigeon
Which of these are correct
Answer:
A
Explanation:
I'm doing that rn and that's the answer
Una sola dosis de etanol, C2 H5 OH, eleva el nivel intracelular de iones calcio. Los iones Ca2+ liberados por el etanol 0,10 M matan las células del hígado de las ratas. Expresa esta concentración en gramos por litro. ¿Cuál es el porcentaje en volumen? (La densidad del etanol es de 0,785 g/mL.)
Answer:
No se bro cual se la respuesta .......
Explanation:
lo siento(
N2 + 3H2 → 2NH3 How many grams of hydrogen are necessary to react completely with 853.42g of nitrogen in the above reaction?
Answer: 182.87 grams of hydrogen are necessary to react completely with 853.42g of nitrogen.
Explanation:
The balanced chemical reaction is :
[tex]N_2+3H_2\rightarrow 2NH_3[/tex]
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
[tex]\text{Number of moles of nitrogen}=\frac{853.42g}{28g/mol}=30.479moles[/tex]
According to stoichiometry:
1 mole of [tex]N_2[/tex] react with = 3 moles of [tex]H_2[/tex]
30.479 moles of [tex]N_2[/tex] will react with=[tex]\frac{3}{1}\times 30.479=91.437moles[/tex] of [tex]H_2[/tex]
Mass of [tex]H_2[/tex] =[tex]moles\times {\text {Molar mass}}=91.437mol\times 2g/mol=182.87g[/tex]
Thus 182.87 grams of hydrogen are necessary to react completely with 853.42g of nitrogen.