The model below shows a part of a human body's muscular system.



Muscles are organs that make movement possible. Which organ system is responsible for controlling muscular movement?


A. Endocrine system


B. Skeletal system


C. Nervous system


D. Digestive system

414 kJ energy is required to melt 2 kg of copper. Hence, option B is correct.

Energy is the capacity for doing work.

Given parameters:

Mass of copper  = 2kg

Unknown:

Amount of energy required to melt the copper  =?

Solution:

To solve this problem, we use:

Q  = m L

m is the mass

L is the latent heat of fusion of copper  = 207kJ/kg

So;

Q = 2 x 207  = 414kJ

Hence, option B is correct.

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an expert in or student of meteorology; a weather forecaster.

Answer: The moles of nitrogen dioxide produced are 96.3

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.

To calculate the moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given volume}}{\text {Molar volume}}=\frac{3714L}{22.4L}=165.8moles[/tex]

[tex]4NH_3(g)+7O_2(g)\rightarrow 4NO_2(g)+6H_2O(g)[/tex]

According to stoichiometry:

7 moles of oxygen [tex](O_2)[/tex] produce = 4 moles of nitrogen dioxide [tex](NO_2)[/tex]

Thus 168.5 moles of oxygen [tex](O_2)[/tex] will produce = [tex]\frac{4}{7}\times 168.5=96.3[/tex] moles of nitrogen dioxide [tex](NO_2)[/tex]

Answer:

0.97 atm ≅ 1 atm

Explanation:

The relation between the pressure (P) and volume (V) of a gas is given by the Boyle's law. According to this, the volume is inversely proportional to the pressure:

P₁ x V₁ = P₂ x V₂

From the problem, we have:

V₁= 400.0 mL x 1 L/1000 mL = 0.4 L

P₁= 5.2 atm

V₂= 2.14 L

We calculate the final pressure (P₂) from the equation, as follows:

P₂ = (P₁ x V₁)/V₂ = (5.2 atm x 0.40 L)/ 2.14 L = 0.97 atm ≅ 1 atm

Therefore, as the volume is increased (from 0.4 L to 2.14 L), the pressure in decreased (from 5.2 atm to 0.97 atm).

A 400.0-mL can contains compressed gas at 5.2 atm. The gas is sprayed into a bag, that inflates to 2.14 L at 0.97 atm.

Boyle's law states that the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature.

A 400.0-mL can contains compressed gas at 5.2 atm. The gas is sprayed into a bag, that inflates to 2.14 L. We can calculate the final pressure of the gas using Boyle's law.

P₁ × V₁ = P₂ × V₂

P₂ = P₁ × V₁ / V₂

P₂ = 5.2 atm × 0.4000 L / 2.14 L = 0.97 atm

where,

A 400.0-mL can contains compressed gas at 5.2 atm. The gas is sprayed into a bag, that inflates to 2.14 L at 0.97 atm.

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Answer/Explanation:

#1 - A pure substance is either an element or a compound, making it different from a mixture. A sample of matter that has specific chemical and physical properties is the only one that fits here.

#2 - A pure substance is either an element or a compound, making it different from a mixture. Water is a compound, and thus this would be true.

#3 - An atom is the smallest unit of an element that keeps the properties of that element. Just refer to its definition.

#4 - A molecule is two or more atoms held together by chemical bonds . Again, just refer to its definition.

#5 - A chemical bond is the attractive force that holds atoms together . Jus refer to its definition.

#6 - Molecules are most definitely not all the same size, especially given the huge number of them. This would be false.

#7 - A compound is a pure substance made up of two or more different types of atoms joined by chemical bonds . Just refer to its definition.

#8 - Compounds always form in a fixed ratio, so this would be false.

#9 - If by directly, the problem means with the naked eye, this would be true.

#10 - False. It's reversed.

#11 - A crystal is a substance in which the particles are arranged in an orderly, geometric, and repeating pattern . Just refer to its definition.

#12 -True; to be more specific, they are covalent network solids.

The translation of the question is

250 g of alcohol have been put in a glass together with 2 g of iodine, which dissolve completely. Calculate the concentration of the solution in% by mass?

Answer:

The %mass by mass of the given solution is 0.794%

Explanation:

We are given

Mass of solute(Iodine) = 2g

Mass of the solvent (Alcohol) = 250g

Since the Iodine dissolves completely in Alcohol

Total mass of the solution = 250 + 2 = 252g

the formula of concentration of the solution in  % by  Mass is given by

%[tex]\frac{w}{W} = \frac{Mass of the solute*100}{Total mass of the solution}[/tex]

%w/W = [tex]\frac{2*100}{252}[/tex]

          = 0.794%

Therefore the %mass by mass of the given solution is 0.794%

Answer:

C based on the number 5, which is easy to use  in calculations

Explanation:

The SI unit system is not based on the number 5.

Answer:

2.11 * 10^3 molecules of phosphoric acid

Explanation:

Answer:

clouds?

Explanation:

im sorry i just wanted the 23 points

Answer: 60.117 g

Explanation: [tex]1.5 mol Ca = \frac{40.078g/mol}{1mol}[/tex] multiply and quit all "mol" and you get the grams

Answer:

simplest explanation regarding CO2 Molecular Geometry and hybridization. ... Carbon is the least electronegative that means it stays at the center

Explanation:

hope this helps

Answer:

1 has the highest density because it has the most amount of circles in the least amount of space- it is the most densely filled with circles; it is the most dense.

Answer:

image 1 would have the highest density

Explanation:

the closer the molecules are the more solid an object is. if the molecules are far apart and rarely bump into eachother, it is more gaseous. the object in the middle (2) is a liquid

Answer:

Explanation:Once energy is added to water by heat from the sun, the bonds between the water molecules gain kinetic energy or energy in motion. Then they escape the surface of the liquid and become a gas (water vapor), which rises into atmosphere.

Answer:

Moles of tin = 0.37 mol

Explanation:

Given data:

Mass of tin oxide = 50 g

Moles of tin = ?

Solution:

Number of moles of SnO:

Number of moles = mass/molar mass

Number of moles = 50 g/ 134.71 g/mol

Number of moles = 0.37 mol

We can see there is only one mole of Sn is present in one mole of tin oxide.

Thus in 0.37 mol  of tin oxide,

0.37 mol × 1 = 0.37 mol of tin

If there are 5 protons, there should be 5 electrons as well. Boron as an electron configuration of 2-3 or 1s2 2s2 2p.

The term proton is defined as a subatomic particle found in the nucleus of every atom. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron.

The protons are considered as elementary particles. The protons are called to be composite particles, containing three valence quarks, and together with neutrons are now classified as hadrons.

Boron has an atomic number of 5. In which it has 5 protons. Therefore, the atom also has 5 electrons. Its atomic mass is 10.811. Thus, it has 11 total particles in its nucleus i.e., protons and neutrons.

Thus,If there are 5 protons, there should be 5 electrons as well. Boron as an electron configuration of 2-3 or 1s2 2s2 2p.

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Answer:

The alteration of the rate of the chemical reaction by the addition of a catalyst will change the dimension of L

Explanation:

The parts of the Energy profile of a reaction diagram the given letters represent are;

K = The energy possessed by the reactants

L = Activation energy required for the reaction to take place

M = Energy threshold required for the reaction to take place

N = The change in the enthalpy from the reactants to the products, which is also the energy released

O = The energy possessed by the products

The addition of a catalyst changes the route with which the reaction takes place such that the reaction rate is increased because the activation energy, L, is reduced.

Therefore, the dimension that will be changed if the rate of reaction were to be altered by a catalyst is L.

Answer:

4.226×10^8

Explanation:

4.2 ×10^8+2.6×10^6=422600000

or 4.226×10^8

Answer:

9.033×10^23 Molecules

Explanation:

We are given,

No.of moles of water = 1.5 moles

The approximate value of Avagadro's Constant =6.022×10^23 particles

Hence,

As we know that,

No.of particles = No.of moles × Avagadro's Constant

Here,

No. Of Water Molecules in 1.5 moles of water = 1.5×6.022×10^23

No.of Water Molecules in 1.5 molesof water=9.033×10^23 Molecules

Answer:

The answer is: Atomic radii decreases from left to right across a period and increases from top to bottom in a group.

Explanation:

Answer:

The longer it takes to orbit the sun.

Explanation:

Answer:

Mass = 26.58 g

Explanation:

Given data:

Mass of lithium nitride = 12.87 g

Mass of lithium hydroxide produces = ?

Solution:

Chemical equation:

Li₃N + 3H₂O     →    3LiOH + NH₃

Number of moles of of Li₃N:

Number of moles = mass/molar mass

Number of moles = 12.87 g/ 34.83 /mol

Number of moles = 0.37 mol

now we will compare the moles of lithium nitride  with lithium hydroxide.

                  Li₃N            :            LiOH

                     1                :             3

                 0.37              :           3/1×0.37 = 1.11 mol

Mass of LiOH:

Mass = number of moles × molar mass

Mass = 1.11 mol × 23.95 g/mol

Mass = 26.58 g

Answer:

Preach!

Explanation:

Answer:

2 and 3 only

Explanation:

The formular for the compound; Silicon(IV)oxide is SO2

1. Silicon atoms form four single bonds in silicon(IV) oxide.

This statement is wrong because the silicon is doubly bonded to two oxygen atoms.

2. Oxygen atoms form two double bonds in silicon(IV) oxide.

This statement is correct.

3. Silicon(IV) oxide has a high melting point.

This statement is correct Due to it's macromolecular structure, it is able to form thousands of covalent bonds between it's sulphur and oxygen sub units.

4. Silicon(IV) oxide contains one silicon atom and four oxygen atoms.

This statement is wrong as silicon(iv) oxide contains only two oxygen atoms.

Answer:

λ = 0.1 nm

E = 2 × 10⁻¹⁵ J

Explanation:

Step 1: Given data

Frequency of X-rays (ν): 3 × 10¹⁸ s⁻¹

Step 2: Calculate the wavelength (λ) of a photon of X-rays

We will use the following expression.

c = λ × ν

where,

c: speed of light

λ = c / ν

λ = (3.00 × 10⁸ m/s) / 3 × 10¹⁸ s⁻¹

λ = 1 × 10⁻¹⁰ m × (10⁹ nm/1 m) = 0.1 nm

Step 3: Calculate the energy (E) of a photon of X-rays

We will use the following expression.

E = h × ν

where,

h: Planck's constant

E = 6.63 × 10⁻³⁴ J.s × 3 × 10¹⁸ s⁻¹

E = 2 × 10⁻¹⁵ J

Answer:

In all of the ecoregions, wind and rain can weather and erode the landforms and soil. Rivers are also

powerful weathering and erosion agents. They can cut into rock and form canyons. When rivers deposit

eroded material, they change their shape or extend the shoreline. When waves along coastlines deposit

sediment, they extend beaches; when they wash sediment away, the waves erode beaches. Rivers, rock

formations, soils, topography, and precipitation in an ecoregion will determine how the processes of

weathering, erosion, and deposition work to reshape it.

Explanation:

The volume of apple juice could  a diabetic person drink : 100 ml

Given

sugar allowance = 8 g

sugar concentration of apple juice : 8.0% w/v

Required

Volume of apple juice

Solution

The concentration of a substance can be expressed in several quantities The concentration shows the amount of solute in a unit of the amount of solvent.

% w/v = mass of solute (weight) in g / 100 ml solution

So for 8% w/v = 8 g of sugar(solute) in 100 ml of apple juice

Answer:

it is an exothermic reaction