help!!!! the relative formula mass (Mr) of sodium fluoride is 42. Use the correct answer frim the box to complete the sentence.​

Answer:

i did not find the amswer sorry

Given that –

We know that –

Then –

[tex]\qquad[/tex][tex]\bf\longrightarrow pOH = 14 -12.5 [/tex]

[tex]\qquad[/tex][tex]\sf \longrightarrow pOH = 1.5[/tex]

[tex]\qquad[/tex][tex]\sf \longrightarrow [OH^- ] = 10^{-1.5 }[/tex]

[tex]\qquad[/tex][tex]\bf \longrightarrow [OH^-] = 3.16 × 10^{-2}[/tex]

Now the number of moles of KOH need to ensure that concentration of Hydroxide anions is equal to –

[tex]\qquad[/tex][tex]\bf \longrightarrow 3.74\: L \times \dfrac{3.16× 10^{-2}}{1 \: L }[/tex]

[tex]\qquad[/tex][tex]\bf \longrightarrow 1. 18 × 10^{-1 }M [/tex]

Volume of the solution contains the need number of moles of Hydroxide anions –

[tex]\qquad[/tex][tex]\sf \longrightarrow \dfrac{ 1.18×10^{-1} \: moles \: OH^-}{0.826 \: moles \: OH^-}[/tex]

[tex]\qquad[/tex][tex]\sf \longrightarrow 0.143 L [/tex]

[tex]\qquad[/tex][tex]\sf \longrightarrow 0.143 \times 1000[/tex]

[tex]\qquad[/tex][tex]\pink{\bf\longrightarrow 143 mL }[/tex]

______________________________________

Answer: D. transverse

Explanation:

Light is a transverse wave, while sound is a longitudinal wave.

Answer:

730 N

Explanation:

force =mass×acceleration

force= 73kg × 10 m/s

f=730N

Answer:

Remember the black and red dots represented in the below animation are not molecules. They are just markers enabling us to visualize the local displacement of air particles and so, the rise and fall of pressure within the wave medium.

The air is made up of many tiny particles. When sound is created, the air particles vibrate and collide with each other, causing the vibrations to pass between air particles. The vibrating particles pass the sound through to a person's ear and vibrate the ear drum. Light travels much faster than sound through air.

Explanation:

Answer:

N, B, Be, C

Explanation:

N (Nitrogen) has 14.0067 B (Boron) has 10.81 Be (Beryllium) has 9 and C (Carbon) has 12

The symbols for every chemical element that has atomic number greater than 3 and atomic mass less than 15.4 u are C, N, O, F, and Ne.

To find elements with atomic number greater than 3 and atomic mass less than 15.4 u, we'll consider the periodic table. Elements with atomic numbers 4 (Be) and higher meet the atomic number criterion. For the atomic mass, we'll look at elements with atomic masses below 15.4 u.

The chemical elements that fulfill both criteria are: Carbon (C) with atomic number 6 and atomic mass 12.01 u, Nitrogen (N) with atomic number 7 and atomic mass 14.01 u, Oxygen (O) with atomic number 8 and atomic mass 16.00 u, Fluorine (F) with atomic number 9 and atomic mass 18.99 u, and Neon (Ne) with atomic number 10 and atomic mass 20.18 u.

These elements meet the conditions of having atomic number greater than 3 and atomic mass less than 15.4 u. Therefore, the symbols for these elements are C, N, O, F, and Ne.

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Answer:

child stage.

Explanation:

they are more vubnlerabke at that stage

Answer:

C 7.5 Moles of MgSO4

Explanation:

Answer:

I think it is a)in freshwater lakes,rivers,and stream

Answer:

a) in freshwater lakes, rivers, and streams

mol = conc × v

= 1.5 × 0.09

= 0.135 moles of HCl

HCl + NaOH > NaCl + H2O

1 mole HCl = 1 mole NaOH

0.135 mol HCl = x

x = 0.135 mol NaOH

mass = mol × molar mass

= 0.135 × 40

= 5.4 g

NaOH = 23 + 16 + 1 = 40 g/mol

I'm not a 100% sure if it's correct

Answer:

B. crest

Explanation:

The highest part of a wavelength is called the crest, meanwhile, the lowest part is the trough.

Answer:

b

Explanation:

it's highest because it have the most higher wave

Answer:

Answer:OK im not 100% sure but it should be the right one

Explanation:

Answer:

1.c

2.c

3.a

4.b

5.a

i think that's the answer

Easy!!

2+17=19

#hope that helps

Answer:

To find the answer you may

2+17=19

Explanation:

so that is the answer I'm sorry,to not give all the solutions

Covalent compounds are generally not very hard because they are formed by two or more nonmetallic atoms.

Covalent compounds are compounds whose constituent elements are joined together by covalent bonds.

Covalent bonding occurs when two or more nonmetallic atoms of an element share valence electrons. This means that covalent compounds will not be physically hard since they constitute non-metals.

Examples of covalent compounds are:

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Answer:

1)  a) 2 C2H2 +  3O2 -->  2CO2 +  2H2O

b) Combustion Reaction

c) Bonds will be broken on the reactant side which will require energy.

d) It agrees with the law of conservation of mass because there are the same amount of molecules of each element on both sides of the equation, meaning mass was not created nor destroyed.

2) a) 2Na + Cl2 --> 2NaCl

        Synthesis

   b) 2Fe + O2 --> 2FeO

        Synthesis

Hope this helps!

Explanation:

To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the balanced equation is

2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O

Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.

a) 2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O is the balanced equation

b)Reaction is a Combustion Reaction

c) energy is required for the breaking of bond.

d) It agrees with the law of conservation of mass as the number  of atoms of each element on reactant and product side is same.

Therefore, the balanced equation is

2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O

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Answer:

c.boron-11

Explanation:

The atomic mass of boron is 10.81 u.

And 10.81 u is a lot closer to 11u than it is to 10u, so there must be more of boron-11.

To convince you fully, we can also do a simple calculation to find the exact proportion of boron-11 using the following formula:

(10u)(x)+(11u)(1−x)100%=10.81u

Where u is the unit for atomic mass and x is the proportion of boron-10 out of the total boron abundance which is 100%.

Solving for x we get:

11u−ux=10.81u

0.19u=ux

x=0.19

1−x=0.81

And thus the abundance of boron-11 is roughly 81%.

Carbohydrates which include sugars and starches are the primary energy sources produced in plants and used by heterotrophic organisms.

Carbohydrates are composed of a basic chemical formula that typically contains a ratio of one Carbon atom for every two Hydrogen atoms and one Oxygen atom C1H2O1. Basically one carbon atom for every one water molecule Carbon + Water = Carbohydrate.

Monosaccharides or Single Carbon Chain Sugars include Glucose C6H12O6

Disaccharides or Double Carbon Chain Sugars include Sucrose C12H22O11

Combining monosaccharides and disaccharides create Polysaccharides which are complex sugars called starches.

Answer:

+65 degress ?

Explanation:

I feel like there is more to this question

The quantity of energy required to heat a piece of iron weighing 1.31 g from 25.0 degrees Celsius to 46.0 degrees Celsius is 2.93 calories.

The ability or power to perform tasks, such as the ability to move an object (having a certain mass) by exerting force.

Energy can exist in many forms, including electrical, mechanical, chemical, thermal, and nuclear, and it can also change its form.

The equation q = mcT, where m is the sample mass, c is the specific heat, and T is the temperature change, can be used to determine the amount of heat acquired or lost by a sample (q).

Q = mcΔT

Q = 1.31 g x 449 x 21° C = 12.26 joule

12.26 /1 x 1 cal / 4.189= 2.93 calories

Therefore, the quantity of energy required to heat a piece of iron is 2.93 cal.

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Answer:

Answer: 0.66 hours

Explanation:

[tex]{ \rm{time = \frac{distance}{speed} }} \\ \\ { \rm{time = \frac{(950.5 \times 1000) \: m}{400 \: m {s}^{ - 1} } }} \\ \\ { \rm{time = {2376.25 \: s}}}[/tex]

• Remember 1 second accounts for 1/3600 hours

[tex]{ \rm{time = \frac{2376.25}{3600} }} \\ \\ { \rm{time = 0.66 \: hours}}[/tex]

The time taken by object  traveling at a speed of 400 m/s to reach 950.5 km distance is 0.66 hr or 39.6 min.

What is average velocity ?

Average velocity is given by the total distance covered by the object in total given time. SI unit of velocity is m/s.

Here in this question it is given that the object is travelling with speed v of 400 m/s and it is to find the time t to reach 950.5 km distance d.

it is known that 1 km = 1000 m

that is 950.5 km = 950500 m

Now, using the relation of speed-distance to find time t to reach 950.5 km distance :

[tex]\begin{aligned}v&=\frac{d}{t}\\t&=\frac{d}{v}\\&=\frac{950500}{400}\\&=2376.25 \text{ s}\end{aligned}[/tex]

Now converting 2376.25 sec into hrs by dividing it by 3600 we get :

2376.25/3600 = 0.66 hr or 39.6 min.

Therefore, the time taken by object to reach 950.5 km distance is 0.66 hr or 39.6 min.

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Answer:

2. 389.15K , 3. 229.15K

Explanation:

K-273.15 = °C

Answer:

true

Explanation:

Because the changes in state of matter would be considered

Answer:

I believe it would be C, The number of atoms in the reactants is equal to the number of atoms composing the products

Explanation:

hope this helps! :D

have a miraculous day!! <3

Answer:

The number of atoms in the reactants is equal to the number of atoms composing the products

Answer:

Starch reacts with Iodine in the presence of Iodide ion to form an intensely colored blue complex, which is visible at very low concentrations of Iodine, making it a very good indicator in both direct and indirect lodometric titrations.

Explanation:

hope this helps

Explanation:

brain and heart froce acts between two chloramine

Answer:

Dispersion, Hydrogen-bonding, and Dipole forces act between two chloramine (NH2CI) molecules.

Explanation:

Dispersion is exerted between all molecules. Chloramine is polar, therefore dipole forces are present. The molecular geometry of chloramine (NH2Cl) is a trigonal pyramidal, therefore hydrogen-bonding forces are present.

Answer:

So, Percentage Composition of Aluminium = 2778×100%=34.62% (approx.) Percentage Composition of Oxygen = 3×1678×100%=61.54% (approx.)