Please can someone answer quickly this do tomorrow morning

Which of the five signs should not be used by themselves?

Precipitate
Temperature change
Color change
Odor
Bubbles

Answer:

The blue star is the hottest star.

Explanation:

Red stars are cooler than the sun, with surface temperatures of 3,500 K for a bright red star and 2,500 K for a dark red star. The hottest stars are blue, with their surface temperatures falling anywhere between 10,000 K and 50,000 K

Answer:

Oxygen does not burn. It is not flammable, but it is an oxidizer.

Explanation

I think you are misunderstanding what is meant by "fire burns up air". Fire does use oxygen when it burns. But it also produces carbon dioxide. An oxygen molecule has two oxygen atoms in it. Fires use this to produce carbon dioxide by adding a single carbon atom from the fire’s fuel (wood, for instance).

hope it'll help:)

Answer:

It should be the answer D. A type of atom

Explanation:

A model is a "synthetic coordination entity that closely approaches the properties of a metal ion in a protein"

An ion is a charged atom.

Answer:

The composition of air can be determined by an experiment which includes passing a known volume of air, measured at a known temperature and pressure, over sufficient amount heated copper granules/powder, and measuring the volume gas remaining after the gas cools down to the temperature at which the first measurement was taken

Oxygen reacts with copper according to the following chemical reaction

2Cu (s) + O₂ (g) → 2CuO (s)

Cupper does not react with the other constituents of air

Whereby the initial volume of air was 100 cm³, we have;

Percentage of oxygen in air = 100 - The final volume reading of the container initially holding the air

When done using am appropriate experimental setup, the percentage of gases remaining equals 79% to 80%, therefore, the percentage composition of oxygen in air is between 20 and 21 percent

Explanation:

Answer:

depends on the element it's reacting with..

Explanation:

if the another element requires less energy to loose electron then zinc will become negatively charged and hence becomes acidic radical..

normally if it is reacting with element with valency 4 and Atomic number less than it(Ti,Si,C) then it will lose electron and gain positive sign and henve becomes basic radical..

Answer:

The answer is below

Explanation:

1. Fractional Distillation

2. Simple Distillation

3. Filtration

4. Steam distillation or lemon grass oil extraction

Answer:

d. 46.5 g

Explanation:

First, you need to start with a properly balanced equation:

N₂H₄(l) + 3O₂(g) -> 2NO₂(g) + 2H₂O(l)

Then, find the moles of water produced:

2H = 2.01568 amu

O = 15.999 amu

________________

18.01468 amu

52.4 g ÷ 18.01468 amu = 2.9087 moles

The mole ratio in our balanced formula between N₂H₄ : H₂O is 1 : 2, so divide moles of H₂O by 2 to get moles of N₂H₄

2.9087 moles ÷ 2 = 1.45435 moles of N₂H₄

Then, calculate the atomic mass of N₂H₄:

2N = 28.0134 amu

4H = 4.03136 amu

________________

32.04476 amu

Finally, calculate the mass in grams of N₂H₄:

1.45435 moles • 32.04476 amu = 46.604 g

Explanation:

here's the answer to your question

Answer:

Cl2(g) + H2O <–> HOCl + H+ + Cl-

Chlorine is the most popular way for the sterilization of water.

Cl2 + H2O → HOCl + HCl

Answer:

[tex]\rm MgBr_2 \cdot 6\, H_2O[/tex].

Explanation:

Let [tex]x[/tex] denote the number of [tex]\rm H_{2}O[/tex] formula units for every [tex]\rm MgCl_{2}[/tex] formula unit. The formula of the hydrate would be [tex]{\rm MgBr_2} \cdot x\, {\rm H_2O}[/tex].

Look up the relative atomic mass of each element on a modern periodic table:

Formula mass:

[tex]\begin{aligned}M({\rm MgBr_{2}}) &= 24.305 + 2 \times 79.904 \\ &= 184.113\; \rm g\cdot mol^{-1}\end{aligned}[/tex].

[tex]\begin{aligned}M({\rm H_{2}O}) &= 2 \times 1.008 + 15.999 \\ &= 18.015\; \rm g\cdot mol^{-1}\end{aligned}[/tex].

The anhydrous compound would be [tex]\rm MgBr_{2}[/tex]. There was [tex]27.21\; \rm g[/tex] of this compound. Calculate the number of moles of formula units in that much of this compound:

[tex]\begin{aligned}n({\rm MgBr_{2}}) &= \frac{m({\rm MgBr_{2}})}{M({\rm MgBr_{2}})} \\ &= \frac{27.21\; \rm g}{184.113\; \rm g \cdot mol^{-1}} \\ &\approx 0.1478\; \rm mol\end{aligned}[/tex].

During heating, [tex]43.19\; \rm g - 27.21\; \rm g = 15.98\; \rm g[/tex] of water [tex]\rm H_{2}O[/tex] escaped from the hydrate. Calculate the number of formula units in that [tex]15.98\; \rm g[/tex] of [tex]\rm H_{2}O\![/tex]:

[tex]\begin{aligned}n({\rm H_{2}O}) &= \frac{m({\rm H_{2}O})}{M({\rm H_{2}O})} \\ &=\frac{43.19\; \rm g - 27.21\; \rm g}{18.015\; \rm g \cdot mol^{-1}} \\&= \frac{15.98\; \rm g}{18.015\; \rm g \cdot mol^{-1}} \\ &\approx 0.887\; \rm mol\end{aligned}[/tex].

In other words, approximately [tex]0.1478\; \rm mol[/tex] of [tex]\rm MgBr_{2}[/tex] formula units (and hence the same number of moles of [tex]{\rm MgBr_2} \cdot x\, {\rm H_2O}[/tex] formula units) contain approximately [tex]0.887\; \rm mol[/tex] of [tex]\rm H_{2}O[/tex] formula units. Calculate the ratio between the two:

[tex]\begin{aligned}x &= \frac{n({\rm H_{2}O})}{n({\rm MgBr_2})} \\ &\approx \frac{0.1478\; \rm mol}{0.887\; \rm mol} \approx 6\end{aligned}[/tex].

Hence, the formula of the hydrate would be [tex]\rm MgBr_2 \cdot 6\, H_2O[/tex].

The scientific question related to the game of basketball is option D: "Do teams that practice more win more games?"

This question is scientific because it explores a cause-and-effect relationship between practice and game outcomes. It can be investigated through empirical observation and data analysis.

To answer this question, researchers could collect data on the practice hours of different basketball teams and compare them to their corresponding game performance. Statistical analysis could be used to determine if there is a correlation between practice time and winning percentage or other performance metrics.

By examining a large sample of teams over an extended period, researchers could draw conclusions about the impact of practice on game outcomes. This scientific inquiry would contribute to the understanding of the factors that influence team success in basketball and could potentially inform training strategies and coaching techniques.

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It's O2 which is oxygen....

Answer:

Explanation:

Hope this helps you. Please mark as brainliest. Good Luck^_^

Answer:

Not all plants do need soil to grow

Explanation:

Not all plants need soil to grow. Some just do better in soil compared to other growing mediums. What plants need are minerals and nutrients, such as nitrogen, potassium, and phosphorous. Soil is an effective way of delivering those nutrients cost-effectively. You can also use alternative delivery systems like hydroponics, aeroponics, and aquaponics to achieve the desired effect. However, these are only suitable for growing shallow-rooted plants. Plants with deep roots will always need soil, as will larger plants with spreading roots.

Answer:. The concentration is decreased and the volume is increased.

Explanation: Diluting a solution means adding more solvent, usually water, meaning that there is less solute in any sample of the solution. Adding more solvent means that the volume of the solution will increase.

Answer:

20,40,60

Explanation:

Let the three parts be 1x, 2x and 3x

The the sum of three parts will be 1x+2x+3x = 120

6x=120

x=120/6

x=20

1x= 20x1=20

2x= 20x2=40

3x= 20x3=60

So 120 is divided in three parts that is 20,40,60

Answer From Gauth Math

Answer:

The current of the toaster is 3.93A

Explanation:

Using the GRASS method:

G: Given: The information that is given is that we have 28Ω of Resistance and 110V of voltage.

R: Required: We need to find the current measured.

A: Action: We can use Ohm's law that relates resistance, voltage and current in the equation:

V = R*I

Or:

I = V/R

Where I is current in A, V is voltage = 110V and R is resistance = 28Ω

S: Solve:

I = 110V / 28Ω

I = 3.93A

S: Statement:

Answer:

the shape would be square planar.

Explanation:

From the question, we can see that the electron geometry is octahedral. Removing the two axial bonds to fit the description, and we have a square planar structure.

Answer:

7.5275 x 10^21

Explanation:

Answer:

[tex]\boxed {\boxed {\sf 3 \times 10^{21} \ atoms \ Hg}}[/tex]

Explanation:

We are asked to find how many atoms are in 1 gram of mercury.

First, we convert grams to moles. We use the molar mass or the mass of 1 mole of a substance. These values are equivalent to the atomic masses on the Periodic Table, but the units are grams per mole instead of atomic mass units.

Look up mercury's molar mass.

We convert using dimensional analysis, so we create a ratio using the molar mass.

[tex]\frac { 200.59 \ g \ Hg}{ 1 \ mol \ Hg}[/tex]

We are converting 1 gram of mercury to moles, so we multiply the ratio by this value.

[tex]1 \ g \ Hg *\frac { 200.59 \ g \ Hg}{ 1 \ mol \ Hg}[/tex]

Flip the ratio so the units of grams of mercury cancel out.

[tex]1 \ g \ Hg *\frac{ 1 \ mol \ Hg} { 200.59 \ g \ Hg}[/tex]

[tex]1 *\frac{ 1 \ mol \ Hg} { 200.59}[/tex]

[tex]\frac{ 1} { 200.59} \ mol \ Hg[/tex]

[tex]0.004985293385 \ mol \ Hg[/tex]

Next, we convert moles to atoms. We use Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units) in 1 mole of a substance. In this case, the particles are atoms of mercury.

We will use dimensional analysis and set up another ratio.

[tex]\frac {6.022 \times 10^{23} \ atoms \ Hg}{ 1 \ mol \ Hg}[/tex]

Multiply by the number of moles we calculated.

[tex]0.004985293385 \ mol \ Hg * \frac {6.022 \times 10^{23} \ atoms \ Hg}{ 1 \ mol \ Hg}[/tex]

The units of moles of mercury cancel.

[tex]0.004985293385 * \frac {6.022 \times 10^{23} \ atoms \ Hg}{ 1 }[/tex]

[tex]3.00214368 \times 10^{21} \ atoms \ Hg[/tex]

The original measurement of grams has 1 significant figures, so our answer must have the same. For the number we calculated, that is the ones place. The 0 in the tenths place tells us to leave the 3 in the ones place.

[tex]3 \times 10^{21} \ atoms \ Hg[/tex]

There are approximately 3×10²¹ atoms of mercury in 1 gram of mercury.

The liquid is a homogeneous mixture because the substance that formed the large crystals was uniformly dissolved.

A solution is composed of a solute and a solvent. A solution is a typical example of a homogeneous mixture.

We define a solution as any combination of solute and solvent. A solution can be regarded as a homogeneous mixture since the solute is uniformly distributed throughout the solution. The solute and solvent constitutes one phase.

When a salt crystal is added to the solution, crystallization is induced and large crystals of solute form.

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A salt crystal is a cubic form of sodium chloride that is closely bounded together by the reaction of sodium and chlorine ions during electrovalent bonding.

Taking a look at a heterogeneous mixture;

It refers to the mixtures that are not thoroughly mixed and uniform in composition.

On the other hand, homogeneous mixtures are formed when a substance i.e. solute (here, it is the salt crystal) is being added to a cool liquid(solvent) is thoroughly mixed.

From the given information, we are being told that when this single salt crystal is added to the cool liquid, large crystals are formed.

This implies that the formation of large crystals is brought about by the action of crystaliization rendering the liquid to be a homogeneous mixture.

We can therefore conclude that the correct statement about the original cool liquid is in Option D.

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the trapped salts go to seawater concentrate

Answer:

Starch solution

Explanation:

Colloidal solutions show tyndall effect and starch solution is a colloidal solution.

Answer:

it's the SI unit of mass (equivalent to

approximately 2.205 lb), first introduced as a unit of mass for the metric system.

Explanation:

There is variety of evidence that supports the claims that plate tectonics accounts for

(1) the distribution of fossils on different continents

,(2) the occurrence of earthquakes, and

(3) continental and ocean floor features including mountains, volcanoes, faults, and trenches.

MARK AS BRAINLIST IF IT IS USEFUL

Answer:

A. Nucleotide

Explanation:

Nucleotides are the monomers that make up nucleic acids, such as DNA and RNA.

Answer:

Any 3 of the following:

atmospheric science

environmental science

climate science

biology

astronomy

human physiology and medicine

Explanation:

Got it right on edge 23

Answe:

Explanation:

số mol của H2S là : 68/22.4=3.03 nha

Answer:

Explanation:

Local unit means a county, city, village, or township.

Answer:

One mole of water was produced from this reaction.

Explanation:

According to this question, the following equation is given as follows:

2H2 + O2 → 2H2O

Two (2) moles of hydrogen gas produces two (2) moles of water in this balanced chemical equation.

If 1 mole of hydrogen gas was used, then:

1 × 2/2 moles of water would be produced

1 mole of water would be produced.

Answer:

One mole of water was produced from this reaction.

Explanation:

Guy above me is right

Answer:

1.76 g

Explanation:

2HgO(s) ==> 2Hg(l) + O2(g)

Number of moles of Hg = 22.3 g/ 201g/mol

= 0.11 moles

From the reaction equation;

2 moles of Hg is formed alongside 1 mole of oxygen

Hence;

0.11 moles of Hg forms 0.11 moles × 1/2

= 0.055 moles of oxygen

Mass of oxygen formed = 0.055 moles of oxygen × 32g/mol = 1.76 g