Need help with 8 plssss

Answer:

sure

Explanation:

The substance formed after heating the mixture of that of Rahul is caleed a compound. Whereas, Manav's mixture still remains in its current stae that is a heterogeneous mixture.

The compound formed is in black in color whereas the mixture is a mix of brownish-red and yellow.

The compound is a homogeneous mixture whereas the mixture is a heterogenous mixture because of its uneven distribution.

Answer:

Problem

Explanation:

The given statement is a problem. It states the problem that the house of the speaker has been undergoing with. This problem gives rise to the Hypothesis in which the 'why' question is asked. The reason of the crumbling of the wood is stated in the hypothesis. Any reason placed of the happening of the event is stated to be hypothesis.

Answer:

D represents the element nitrogen which will gain three valence electrons forming a 3 ion.

Answer:

answer is

Explanation:

D

Answer:

7.71 × 10⁻⁴ M/s

Explanation:

The initial rate of the reaction can be expressed by using the formula:

[tex]\dfrac{\Delta [O_2]}{\Delta t}[/tex]

where the number of moles of O₂ = [tex]\dfrac{PV}{RT}[/tex]

where;

Pressue P = 1.00 atm

Volume V =5.74mL =  (5.74 /1000) L

Rate R = 0.082 L atm/mol.K

Temperature = 298 K

[tex]= \dfrac{1.00 \ atm \times \dfrac{5.74 }{1000}L}{0.082 \ L \ atm/mol.K \times 298 K}[/tex]

= 2.35 × 10⁻⁴ mol

Δ[O₂] = [tex]\dfrac{moles \ produced - initial \ mole}{\dfrac{5.08 }{1000}L }[/tex]

Δ[O₂] = [tex]\dfrac{2.35 \times 10^{-4} M - 0 M}{\dfrac{5.08 }{1000}}[/tex]

Δ[O₂]  = 0.04626 M

The initial rate = [tex]\dfrac{\Delta [O_2]}{\Delta t}[/tex]

= [tex]\dfrac{0.04626}{60}[/tex]

= 7.71 × 10⁻⁴ M/s

Answer:

One mole of Al weighs 27g.

2.5 moles of Al weigh 67.5g.

Answer:

molecules can be much bigger. one molecule of vitamin c is made up of 20 atoms (6 carbons, 8 hydrogens, and 6 oxygens

Answer:

Test tube 1  0.10 M HCL

Test tube 2  0.10 M KOH

Test tube 3 0.10 M Na2CO3

Explanation:

From the question we are told that

    A few drops of the solutions from test tube 1 added to a similar volume of the solution in test tube 2 produces no visible reaction but the solution becomes warm

Generally this warmth is as a result of a reaction between an acid and a base and the acid is 0.10 M HCL and the base is  0.10 M KOH , the heat generated is know as the heat of neutralization,

The reaction is  

       [tex]HCl_{(aq)} + KOH_{(aq)} \rightarrow KCl_{(aq)} + H_2O_{(l)} + \Delta H[/tex]

We are also told from the reaction that

A few drops of the solution from test tube 1 added to a similar volume of the solution in test tube 3 produces carbon dioxide gas.

Generally  carbon dioxide gas  is produced is as a result of  a reaction between the acid HCl  and Na2CO3.

The reaction is

        [tex]2HCl -{(aq)} + Na_2 CO_3_{(aq)} \rightarrow 2 NaCl _{(aq)} + CO_2_{(g)} + H_2O_{(l)}[/tex]

Hence from this explanation above we see that the solution in test tube 1 is  0.10 M HCL while solution in test tube 2 is 0.10 M KOH and then solution in test tube three is  0.10 M Na2CO3

Answer:

Explanation:

We shall use the formula S₁V₁ = S₂V₂

S₁ = .1180 M , V₁ = 25.98 mL

S₂ = ? , V₂ = 52.50 mL

.1180 M  x 25.98 = 52.50 x S₂

S₂ = .0584 M

Molarity of the acid solution = .0584 M .

The concentration of the acid solution is 0.058 M.

The equation of the reaction is;

CH3COOH(aq) + KOH(aq) ----->  CH3COOK(aq) + H2O(l)

The following are known;

Concentration of base CB = 0.1180 M

Volume of base VB =  25.98 mL

Concentration of acid CA = ?

Volume of acid VA = 52.50 mL

Number of moles of acid NA = 1

Number of moles of base NB = 1

Using;

CAVA/CBVB =NA/NB

CAVANB = CBVBNA

CA=  CBVBNA/VANB

CA = 0.1180 M × 25.98 mL × 1/52.50 mL × 1

CA = 0.058 M

Learn more: https://brainly.com/question/24381583

Answer:

acidic because of electrical issues and the body of electrical equipment

Answer:

height = 4.74 cm

density = 2.23 g/ cm³

Explanation:

Mass of metal = 0.650 kg (650 g)

Width = 0.136 m    

Length = 0.0451 m  

Volume of metal = 291 cm³

Height in cm = ?

density of metal =?

Solution:

Width = 0.136 m    (0.136 m×100 cm/1m = 13.6 cm)

Length = 0.0451 m  (0.0451 m×100 cm/1m = 4.51 cm)

First of all we will calculate the height:

Volume = height× width× length

291 cm³ =      h     × 13.6 cm × 4.51 cm

291 cm³ =      h     × 61.34 cm²

h = 291 cm³ / 61.34 cm²

h = 4.74 cm

Density:

d = m/v

d = 650 g/291 cm³

d = 2.23 g/ cm³

Answer: A) The angle of the Sun's rays!

Answer:

A) The angle of the Sun's rays!

Explanation:

The question is incomplete, the complete question is:

This is the chemical formula for cassiterite (tin ore): SnO2 A geochemist has determined by measurements that there are 13. moles of tin in a sample of cassiterite. How many moles of oxygen are in the sample? Round your answer to 2 significant digits.

Answer:

Explanation:

In SnO2, there are two moles of oxygen for each mole of tin.

Hence, if there are 13 moles of tin, then we should have 13 * 2 moles of oxygen. This gives us 26 moles of oxygen.

Hence there are 26 moles of oxygen.

Answer:

9.) Homeostasis

10.) Epidermis

11.) Cytoplasim

12.) Classification

Answer:evaporation

Explanation:

Answer:

Pretty sure its evaporation, if its not I'm very sorry.

Answer:

the bike will go down 5 N

Answer:

QC= [O2]^3/[F2]^10

Explanation:

Answer:

C) an increase in rate of reaction because reactant molecules collide with greater energy

Explanation:

Temperature is one of the factors that affect the rate of a reaction. The rate of a reaction increases with an increase in temperature and vice versa. When the temperature of a reaction increases, the kinetic energy of the reactant molecules increases causing them to react at a faster rate.

The reactant molecules respond to an increase in temperature by colliding at a faster rate due to an increased kinetic energy between the reactant molecules.

Answer : [tex]BaCl_2[/tex] reagent predict to be in excess.

Explanation : Given,

Concentration of [tex]BaCl_2[/tex] = 0.10 M

Volume of [tex]BaCl_2[/tex] = 7.50 mL = 0.0075 L       (1 L = 1000 mL)

Concentration of [tex]KIO_3[/tex] = 0.10 M

Volume of [tex]KIO_3[/tex] = 7.50 mL = 0.0075 L

First we have to calculate the moles of [tex]BaCl_2[/tex]  and [tex]KIO_3[/tex].

[tex]\text{Moles of }BaCl_2=\text{Concentration of }BaCl_2\times \text{Volume of }BaCl_2[/tex]

[tex]\text{Moles of }BaCl_2=0.10M\times 0.0075L=0.00075mol[/tex]

and,

[tex]\text{Moles of }KIO_3=\text{Concentration of }KIO_3\times \text{Volume of }KIO_3[/tex]

[tex]\text{Moles of }KIO_3=0.10M\times 0.0075L=0.00075mol[/tex]

Now we have to calculate the excess and limiting reagent.

The balanced equilibrium reaction will be:

[tex]BaCl_2+2KIO_3\rightleftharpoons Ba(IO_3)_2+2KCl [/tex]

From the balanced reaction we conclude that

As, 2 mole of [tex]KIO_3[/tex] react with 1 mole of [tex]BaCl_2[/tex]

So, 0.00075 moles of [tex]KIO_3[/tex] react with [tex]\frac{0.00075}{2}=0.000375[/tex] moles of [tex]BaCl_2[/tex]

From this we conclude that, [tex]BaCl_2[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]KIO_3[/tex] is a limiting reagent and it limits the formation of product.

Hence, [tex]BaCl_2[/tex] reagent predict to be in excess.

Answer:

Be2^+

Explanation:

Ionic diameter increases down the group. This implies that Be2^+ will have the smallest diameter.

This extremely small diameter makes Be2^+ to differ considerably from other ions of group 2 elements.

For instance, the compounds of beryllium are mostly covalent in nature.

Answer: it is covalent and there are 2 hydrogen molecules and 1 oxygen molecule.

Explanation: it just is

Answer:

a right is 90 degrees

Answer:

Explanation:

We are to carefully sketch a curve that relates to the potential energy of two O atoms versus the distance between their nuclei.

From the diagram, O2 have higher potential energy than the N2 molecule. Because on the periodic table, the atomic size increases from left to right on across the period, thus O2 posses a larger atomic size than N2 atom.

Therefore, the bond length formation between the two O atoms will be larger compared to that of the two N atoms.

Answer:

a) - 0.2 M

b) - 0.2 M

c)- 0

Explanation:

The chemical formula of copper (II) bromide is CuBr₂. Its molar mass (MM) is calculated as follows:

MM(CuBr₂)= MM(Cu) + (2 x MM(Br) = 63.5 g/mol + (2 x 80 g/mol)= 223.5 g/mol

a). Molarity = moles CuBr₂/1 L solution

moles CuBr₂ = mass/MM = 18.7 g x 1 mol/223.5 g = 0.084 mol

Volume in L = 375 mL x 1 L/1000 mL = 0.375 L

M = 0.084 mol/(0.375 L) = 0.223 M ≅ 0.2 M

b). When is added to water, CuBr₂ dissociates into ions as follows:

CuBr₂ ⇒ Cu²⁺ + 2 Br⁻

We have 1 mol Cu²⁺ (copper (II) cation) per mol of CuBr₂. Thus, the concentration of copper (II) cation is:

0.2 mol CuBr₂ x 1 mol Cu²⁺/mol CuBr₂ = 0.2 M

c). The concentration of acetate anion is 0. There is no acetate anion in the solution (the anion from CuBr₂ is bromide Br⁻).

Answer:

Explanation:

energy of solar radiation = 70 W / m²

energy absorbed in 1 hour by an area of .18 m²

= 70 x .5 x .18 x 60 x 60 J

= 22.68 x 10³ J

bond energy of i mole bond = 348 x 10³ J

bond energy of 6.02 x 10²³ bonds = 348 x 10³  J

bond energy of one bond = 57.8 x 10⁻²⁰ J  

No of bonds broken by energy 22.68 x 10³

= 22.68 x 10³  / 57.8 x 10⁻²⁰

= .3923 x 10²³

= 39.23 x 10²⁰ .

Answer:

The change in the internal energy of the system -878 J

Explanation:

Given;

energy lost by the system due to heat, Q = -1189 J (negative because energy was lost by the system)

Work done on the system, W = -311 J (negative because work was done on the system)

change in internal energy of the system, Δ U = ?

First law of thermodynamics states that the change in internal energy of a system (ΔU) equals the net heat transfer into the system (Q) minus the net work done by the system (W).

ΔU = Q - W

ΔU = -1189 - (-311)

ΔU = -1189 + 311

ΔU = -878 J

Therefore, the change in the internal energy of the system -878 J

Answer:

2 and a half hours

Explanation:

Time is equal to distance over speed

Answer:

i

[tex]J_{m} = 20 [/tex]

ii

[tex]J_{m} = 22.5 [/tex]

Explanation:

From the question we are told that

  The first temperatures is [tex]T_1 =  25^oC =  25 +273 =298 \ K[/tex]

   The second temperature is  [tex]T_2 =  100^oC =  100 +273 = 373 \ K[/tex]

Generally the equation for  the most highly populated rotational energy level is mathematically represented as

     [tex]J_{m} = [ \frac{RT}{2B}]  ^{\frac{1}{2} } - \frac{1}{2}[/tex]

Here R is the gas constant with value [tex]R =8.314 \ J\cdot K^{-1} \cdot mol^{-1}[/tex]

Also  

      B is given as [tex]B=\ 0.244 \ cm^{-1}[/tex]

   Generally the energy require per mole to move 1 cm is  12 J /mole

So   [tex]0.244 \ cm^{-1}[/tex]  will require x J/mole

           [tex]x =  0.244 *  12[/tex]

=>          [tex]x =  2.928 \ J/mol [/tex]

So at the first temperature

     [tex]J_{m} = [ \frac{8.314 * 298  }{2*  2.928 }]  ^{\frac{1}{2} } - 0.5 [/tex]

=>  [tex]J_{m} = 20 [/tex]

So at the second temperature

           [tex]J_{m} = [ \frac{8.314 * 373  }{2*  2.928 }]  ^{\frac{1}{2} } - 0.5 [/tex]

=>  [tex]J_{m} = 22.5 [/tex]

Answer:

Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.

Explanation: