Grade7science
Can somebody plz help answer this science question ? (Will mark brainliest whoever amasses first) :DDD!

The definition of the meter in biology is that the meter scale is used to measure the length. it is first unit of the international system of the units.

The meter is the first unit of the length in the international system of the units. currently the definition of the meter is : The meter can be defined as the length of the path that is travelled by the light in the vacuum during the time interval of 1 / 2999792458 second. The symbol of the meter is m.

The meter scale is used to measure the length or the distance between the two points.

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The concentration of the final solution is 1.41[tex]\frac{mol}{L}[/tex].

Now, first calculate the number of moles of first solution:

[tex]M_{1} =\frac{no. of moles of solution}{total volume of solution}[/tex]

no. of moles we have to find

total volume is 0.0352L and molarity of solution is 1.66M

The total number of moles of solute present in a given solution per litre is known as its molarity. In contrast to mass, which varies as the system's physical circumstances vary, the volume of a solution changes as a function of changes in the system's physical qualities, such as pressure and temperature. This has an impact on the molality of the solution. The symbol M, sometimes known as a molar, denotes molarity.

[tex]1.66=\frac{n}{0.0352}[/tex]

on solving we get,

n=0.0584 mol

Now, find the number of moles of second solution by the same formula used to find the moles of first solution,

molarity of second solution is 0.892M and total volume is 0.0167L

Now, put the values in the formula,

[tex]0.892=\frac{m}{0.0167}[/tex]

On solving we get,

m=0.0149 mol

and to find the concentration of new solution number of moles is equal to the sum of moles of first solution and second solution.

x=m+n

x=0.0584+0.0149

x=0.0733 mol

Now, molar concentration is,

[tex]M=\frac{x}{V}[/tex]

[tex]M=\frac{0.0733}{0.352+0.0167}[/tex]

On solving we get,

M=1.41[tex]\frac{mol}{L}[/tex]

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Lithium has a valence of 1, so it will not usually reach an octet in a bond. It tends to form ionic bonds, in which there is only one electron transfer, rather than two or more which would be required to reach an octet.

Lithium is a soft, silver-white metal that is the lightest of all alkali metals. It is a key component in many batteries, and is also used in a variety of other applications. It has a low reactivity, and is relatively stable when exposed to air and water. In its elemental form, Lithium is a highly flammable, corrosive metal that is rarely found in its pure form in nature. It can be found in minerals such as lepidolite and spodumene, and is commonly mined from salt flats and brine pools.

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Thermal energy always moves from higher energy area to lower energy area over a temperature gradient.

Thermal energy is a form of energy by virtue of temperature of a body. As the temperature of a body increase its thermal energy increases. Thermal energy or heat energy transfers though medium and vacuum from higher energy area to lower energy area.

Heat transfer can be through conduction in solids, convection in fluids and by radiation through space. In conduction, the thermal energy easily transfers through a chain of close packed molecules.

In all these mode of heat transfer heat energy is flowing from a hotter region to a colder region.

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Answer:

0.693 (you can round it up if you want to)

Explanation:

Density= mass ÷ volume

54.2 ÷ 78.1 = 0.693

I hope this helped☺

Cobalt-60 has a half-life of 5.20 years, which means that half the sample will be present after that time.

The chemical element cobalt has the atomic number 27 and the symbol Co. It is a naturally occurring hard, glossy, silver-gray metal that is found in rocks and soils. Cobalt is magnetic when it is pure, and it can be used to make alloys, magnets, and colours. Additionally, it is employed in the manufacture of batteries, catalysis, and pharmaceuticals. The production of vitamins and proteins depends on cobalt, a trace mineral that is crucial for maintaining human health.

After 7.55 years, about 0.78 of the original 1.000 mg sample will remain.
Therefore, 0.78 x 1.000 mg = 0.780 mg will remain after 7.55 years.

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Matter with a Dull luster reflects little light from its surface.

Minerals with dull luster reflect very little light.

The term "luster" refers to the light reflection from a mineral's surface. To define lustre, mineralogists use specific terminology. The mineral's metallic or non-metallic nature can be used to categorise lustre in a straightforward manner. Metallic lustre can be seen in opaque, sparkling minerals like pyrite. Quartz is one example of a mineral with a non-metallic shine.

Due to their coarse granulations, which scatter light in all directions and resemble a Lambertian reflector, dull (or earthy) minerals have little to no shine. Kaolinite is one Example.

Luster                  Appearance

Adamantine            Sparkly

Earthy                    Dull, clay-like

Pearly                    Pearl-like

Resinous            Like resins, such as tree sap

Silky                    Soft-looking with long fibers

Vitreous                    Glassy

Minerals are inorganic solids that exist in nature and have a distinct chemical composition and crystal lattice structure. Even though thousands of minerals in the earth have been found, only ten minerals—plagioclase, quartz, orthoclase, amphibole, pyroxene, olivine, calcite, biotite, garnet, and clay—make up the majority of the crust's volume.

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The order of decreasing bond angle for the given molecules is :

O OF2 > NH3 > CCl4 > CO2

In molecules with a central atom, the bond angle is determined by the electron pair-bond pair repulsion. The bond angle decreases as the number of electron pair-bond pair increases. In OF2 the central atom is O, and it has 2 lone pairs and 2 single bonds, the bond angle is expected to be smaller than in the other molecules.In NH3, the central atom is N, and it has 3 single bonds and 1 lone pair, the bond angle is expected to be larger than in OF2 but smaller than in CO2 and CCl4. In CO2 and CCl4, the central atoms are C and Cl respectively, and they have 4 single bonds and no lone pairs, the bond angle is expected to be larger than in NH3, but smaller than in OF2.

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The product of the reaction between 2-butene and hydroiodic acid (HI) is 2-iodobutane.

The reaction mechanism involves a nucleophilic substitution, where the iodine atom in HI acts as the nucleophile and attacks the carbon atom in the double bond of 2-butene. This results in the formation of a carbocation intermediate, which then undergoes a rearrangement to form 2-iodobutane. The overall reaction can be represented as follows: 2-butene + HI → 2-iodobutane + H2.Nucleophilic substitution is a type of chemical reaction in which a nucleophile (a molecule or ion with a lone pair of electrons) attacks an electron deficient species, known as an electrophile, to form a new chemical bond. In the process, the electrophile's original electron pair is replaced by the nucleophile. Nucleophilic substitution reactions can occur in a variety of ways, such as S N 1, S N 2, and S Ni (where i = 1, 2, or any other number).

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Answer: 71.43g

Explanation: The RMM of NaHCO3 is

23+1+12+16(3)=84.

There is one carbon in NaHCO3 thus there are 1×12g of C in NaHCO3.

Thus

85gNaHCO3-----12g C

500gNaHCO3---- xgram

(500×12)÷84= 71.43

Given :

0.26 mole of [tex]K_3PO_4[/tex] and 0.35 L of water.

To Find :

The molarity of a solution of [tex]K_3PO_4[/tex] made by mixing 0.26 mole of potassium

phosphate with water up to 0.35 L .

Solution :

We know, molarity is given by :

[tex]M = \dfrac{number \ of \ moles }{Volume \ in \ Liter}\\\\M = \dfrac{0.26}{0.35}\ M\\\\M = 0.743 \ M[/tex]

Therefore, the molarity of [tex]K_3PO_4[/tex] solution is 0.743 M.

The specific heat of water is equal to 1200 joules / (36 grams × (240C - 220C)) = 16.7 joules/gram・°C.

Temperature is a measure of the average kinetic energy of the particles in a material. It is measured in degrees on the Celsius, Kelvin and Fahrenheit scales. Temperature is an important factor in many physical and chemical processes, such as the rate of chemical reactions, the speed of sound, the intensity of light and the properties of gases.

The specific heat of water, c, is calculated using the equation c = Q / (m × ΔT), where Q is the amount of heat energy, m is the mass of the sample and ΔT is the change in temperature.

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The number of moles must be equal, the ratio of the molarity of each must be equal to the ratio of the volumes used.

An experiment is a procedure or set of procedures used to test a hypothesis or explore a cause and effect relationship. It is a scientific method of investigation in which the investigator manipulates one or more independent variables and measures the subsequent effect on one or more dependent variables. Experiments are conducted to answer questions, test theories, and gain insight into cause-and-effect relationships.

The molarity of the HNO 3 solution can be calculated using the equation:
Molarity of HNO3 = (volume of HNO3 * molarity of Ba(OH)2) / volume of Ba(OH)2
Molarity of HNO3 = (14.5 mL * 1.75 x 10^-2 M) / 12.5 mL
Molarity of HNO3 = 1.4 x 10^-2 M
This equation works because the number of moles of HNO3 neutralized by the Ba(OH)2 must be equal to the number of moles of Ba(OH)2 used. The number of moles of each can be determined by multiplying the molarity of each by the volume used, and since the number of moles must be equal

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slate is the correct answer i PROMISE

(. ^ ᴗ ^.)

Answer:

Acetic acid , systematically named ethanoic acid , is a colourless liquid organic compound with the chemical formula CH3COOH.

Explanation:

3.4 mole of H₂SO₄ are needed to react completely with 6.8 moles of lithium hydroxide (LiOH).

When breathed in, lithium hydroxide monohydrate can have an impact on you. Lithium Hydroxide Monohydrate is a HIGHLY CORROSIVE CHEMICAL, and contact with it can cause serious skin irritation, eye damage, and burning. Lithium Hydroxide Monohydrate inhaled can irritate the throat and nose.

From the stichiometry of the reaction: 2 LiOH + H2SO4 → Li2SO4 + 2H2O

It is evident that 2.0 moles of LiOH reacts with 1.0 mole of H2SO4 to produce 1.0 mole of Li2SO4 and 2.0 moles of H2O.

Using cross multiplication:

1.0 mole of H2SO4 reacts completely with → 2.0 moles of LiOH

x mole of H2SO4 are needed to react completely with → 6.8 moles of LiOH

since number of moles of H2SO4 = ( 1.0 x 6.8 ) / (2.0) = 3.4 mole of H2SO4.

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Answer:

The last one is true.

The balanced chemical equation is N₂ + 3 H₂[tex]\rightarrow[/tex] 2 NH₃ which gives the formation of ammonia.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

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Human population growth will Double time and that will be 41.17 years

Human growth can be defined as;

The growth and development are positively influenced by factors, like parental health and genetic composition.

Population growth is the increase in the number of humans on Earth.

Human population has grown exponentially over the past century. It has done so largely by producing large amounts of food, and learning how to control disease.

We can find what year the human population would double using the rule of 70. This is given as;

Double time = 70 / rate(r)

Double time = ?

Rate = 1.7%

Inserting into the equation;

Double time = 70 / 1.7

Double time =41.17 years

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Answer:

i think her journey was 680 km/h long

Answer:

6.67 hours

Explanation:

(800 km) / (120 km/hr) = 6.67 hours

Answer:

2H2+O2=2H2o

Explanation:

We have 2 hydrogens, 2 oxygens on the left-hand side.

But only 1 O on the right-hand side.

let's place a 2 before H2O (water)

Do you drink H2O every day?

But balancing the O unbalanced H

So the balanced chemical equation will look like this:

2H2O+O2=2H2O

If a laboratory employee has 12.0 grammes of potassium metal, the theoretical yield of potassium oxide that even the scientist may theoretically make from the reaction with oxygen gas is 14.5 gram of K2O.

In chemistry, yield, also known as reaction yield, is a measurement of the number of moles of a product created in ratio to the reactant consumed in a chemical reaction, generally represented as a percentage. Before performing chemical reactions, it is necessary to know how many product will be produced with certain reactant quantities. This is referring to the theoretical yield.

This approach is useful for calculating the theoretical yield of such a chemical process. The yield of a reaction represents how much product is generated by that reaction. The theoretical yield is the amount of product predicted by stoichiometry, whereas the actual yield is the amount produced.

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Answer:

Student C.

Explanation:

At higher temperatures, the particles move faster and collide with each other more frequently, which causes the gas to occupy a larger volume. At lower temperatures, the particles move slower and collide less frequently, which causes the gas to occupy a smaller volume.

When the balloon is placed in the freezer, the temperature inside the balloon will also decrease, causing the gas particles to slow down and collide less frequently, which leads to a decrease in the volume of the gas, hence the balloon will shrink or contract. On the other hand, the room temperature balloon will experience no significant change in the temperature and the gas particles inside the balloon will remain at the same level of activity, causing the balloon to retain the same volume.

Option C. Decomposition reaction: a substance involved is oxygen.

A decomposition reaction is a type of chemical reaction where a single compound is broken down into two or more simpler substances. In the reaction, energy is typically used to break down the bonds that hold the molecules of the compound together. Oxygen is often a substance involved in the reaction, as it is used to provide the energy needed to break down the compound. When oxygen is involved, the reaction is sometimes referred to as an oxidation reaction.

Since the question is not complete, here's the full task:

Which of the following statements correctly identifies the decomposition reaction and describes a substance involved?

Choose the right option:

A. Combustion reaction: a substance involved is oxygen

B. Combustion reaction: a substance involved is a hydrocarbon

C. Decomposition reaction: a substance involved is oxygen

D. Decomposition reaction: a substance involved is a hydrocarbon

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The mole ratio of the reactants and products is

a. 2 : 1 : 2

b. 1: 2:1:1

The ratio of the mole quantities of any two compounds present in a balanced chemical reaction is known as the mole ratio. A comparison of the ratios of the molecules required to accomplish the reaction is given by the balancing chemical equation. The coefficients of each species in the reactants and products are used to calculate the mole ratio of the reactants and products. The mole ratio of the reactants and products, as demonstrated by the equation in the question, is 2: 1: 2 and 1:2:1:1 respectively.

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As the number of carbon atoms increases the phase changes from gas to liquid,length of chain increases and also the boiling point increases in case of alkanes, alkenes, and alkynes.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

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A carbonyl group is bound to hydrogen bond or to a hydrogen ion and an alkoxy substituent in an organic compound known as an aldehyde.

Aldehyde is an organic compound containing a functional group with the structure −CHO, in which a carbon atom is double-bonded to an oxygen atom and single-bonded to a hydrogen atom. Aldehydes are the simplest type of carbonyl group and the most common type of organic compound. Aldehydes are found in many natural and manufactured products, including perfumes and food products. The most common example of a natural aldehyde is formaldehyde, which is produced by plants and animals.

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