i need help with this science pls

Answer:

Option A is correct.

Option D is correct.

E is the correct answer

Explanation:

This a theoretical calorimetry problem that can be solved by thermodynamic concepts.

Our system is the unknown solid. If the temperature of water has increased, we can think, that the heat from the metal was absorbed by water, which is our surrounding. If in the analysis of the situation we use a calorimeter, knowing that it is an isolated system, which does not allow the entry or exit of heat, we can conclude that the heat released is equal to the heat absorbed.

In conclusion, the thermodynamic system is constituted by the chemical reaction. In this case, the surrounding is made up of water and the calorimeter itself.

Answer:

The correct answer is A :))

Answer:

  58.0 g/mol

Explanation:

At STP, one mole occupies 22.4 liters. One mole of the hydrocarbon would have a mass of ...

  (2.59 g/L)(22.4 L/mol) ≈ 58.0 g/mol

Answer:

Answer:

Although you might think of a machine as complex system of gears, drive belts and and a motor, the definition physicists use is much simpler. A machine is simply a device that does work, and there are only six different types of simple machines. They include the lever, the pulley, the wheel and axle, the screw, the wedge and the inclined plane.

Explanation:

Answer:

Atoms are neutral; they contain the same number of protons as electrons. By definition, an ion is an electrically charged particle produced by either removing electrons from a neutral atom to give a positive ion or adding electrons to a neutral atom to give a negative ion.

Explanation:

:)

Answer:

Is zygote fungi an option??

Answer:

zygote fungi

Explanation:

i got the answer right

Answer:

a period

Explanation:

Answer: The row of elements across the periodic table is called "periods".

Explanation:

In the Periodic Table, there are seven rows of elements, which is called periods.

Answer:

Kinetic

Explanation:

When the ball is falling towards the table, it has kinetic energy. This elastic potential energy is why the ball is able to bounce, or rebound. After the ball rebounds, the elastic potential energy is transformed into kinetic energy, but it will never possess as much kinetic energy as during its original fall.

Answer:

Explanation:

It has kinetic energy.

Hope it helped you.

Answer:

1.661 mol.

Explanation:

Hello!

In this case, since the Avogadro's number allows us to relate the number of formula units in one mole of the substance; we need to keep in mind that elements are related by atoms and compounds by molecules, it means:

[tex]1 mol = 6.022x10^{23}atoms\\\\1 mol = 6.022x10^{23}molecules[/tex]

Thus, for copper (I) oxide, we compute the moles, given the atoms as shown below:

[tex]n = 1.900x10^{24}molecules*\frac{1mol}{ 6.022x10^{23}molecules} \\\\n = 1.661mol[/tex]

Thus, the method we use is the same.

Best regards

Answer: C

Explanation:

It gives kinetic energy to the molecules and it breaks the bonds faster because they jiggle more

Answer:

B. 2A1 + 3Zn(NO3)2 --> 2AI(NO3)3 + 3Zn​

Explanation:

In the chemical equation, you can see that 2Al replaced 3Zn with (NO3)3 in the product, thus it is a single displacement reaction.

Answer:

B. 2A1 + 3Zn(NO3)2 --> 2AI(NO3)3 + 3Zn​

Explanation:

Answer:

No change to the cation  Add -ide to the anion

Question 1 and .2

Explanation:

Answer:

false

Explanation:

if it is lower than 7 It is acid

Answer:

the lattice constant is 0.270 inches

Explanation:

Given the data in the question;

For FCC lattice;

a = b = c, ∝ = β = α = 90°

from the image below;

AC = 0.19 + 0.19/2 + 0.19/2 + 2(0.001) inch

AC = 0.19 + 0.095 + 0.095 + 0.002

AC = 0.382 inches

Now using Pythagoras theorem

AC² = AB² + BC²

since a = b = c

AC² = a² + a²

(0.382)² = 2a²

2a² = 0.145924

a² = 0.145924 / 2

a² = 0.072962

a = √0.072962

a =  0.27011 ≈ 0.270 inches

Therefore, the lattice constant is 0.270 inches

Explanation:

Structural Formulas v. Empirical Formulas

An empirical formula (like a molecular formula) lacks any structural information about the positioning or bonding of atoms in a molecule. It can therefore describe a number of different structures, or isomers, with varying physical properties. For butane and isobutane, the empirical formula for both molecules is C2H5, and they share the same molecular formula, C4H10. However, one structural representation for butane is CH3CH2CH2CH3, while isobutane can be described using the structural formula (CH3)3CH.

Answer:3.50 cm

Explanation:

Answer:

3.63cm

Explanation:

Answer:

The answer is "Choice A and Choice B"

Explanation:

The Zero-Order reactions are usually found if a substrate, like a surface or even a catalyst, is penetrated also by reactants. Its success rate doesn't depend mostly on the amounts of the various reaction in this reaction.

Let the Rate = k

As [tex]\frac{dx}{dt} \ rate\ \ K_0[/tex] doesn't depend on reaction rate, a higher reaction rate does not intensify the reaction.

By the rate [tex]k_0 =\frac{dx}{dt},[/tex] the created based and the reaction rate is about the same.

Below statement are correct about zero order reaction.

Zero-order reaction is a chemical reaction in which the rate of chemical reaction does not change with increase or decrease in the concentration of the reactants.

Example is the decomposition of ammonia to nitrogen and hydrogen. the rate does not vary, it is the same.

Therefore, Below statement are correct about zero order reaction.

Learn more about zero order reaction from the link below.

https://brainly.com/question/13314785

The combination from the available option that will make a solution would be sugar and water.

Solutions are obtained when solutes dissolve in solvents.

In other words, a solute must be able to dissolve in a solvent before a solution can be formed.

Oil and water cannot mix, and thus, cannot form a solution. Sand is insoluble in water and ice and water are the same.

Thus, the only option left is sugar and water. Sugar dissolves in water to form a sugar solution.

More on solutions can be found here: https://brainly.com/question/7932885

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Answer: The activation energy Ea for this reaction is 22689.8 J/mol

Explanation:

According to Arrhenius equation with change in temperature, the formula is as follows.

[tex]ln \frac{k_{2}}{k_{1}} = \frac{-E_{a}}{R}[\frac{1}{T_{2}} - \frac{1}{T_{1}}][/tex]

[tex]k_1[/tex] = rate constant at temperature [tex]T_1[/tex] = [tex]2.3\times 10^8[/tex]

[tex]k_2[/tex] = rate constant at temperature [tex]T_2[/tex] = [tex]4.8\times 10^8[/tex]

[tex]E_a[/tex]= activation energy = ?

R= gas constant = 8.314 J/kmol

[tex]T_1[/tex] = temperature = [tex]280.0^0C=(273+280)=553K[/tex]

[tex]T_2[/tex] = temperature = [tex]376.0^0C=(273+376)=649K[/tex]

Putting in the values ::

[tex]ln \frac{4.8\times 10^8}{2.3\times 10^8} = \frac{-E_{a}}{8.314}[\frac{1}{649} - \frac{1}{553}][/tex]

[tex]E_a=22689.8J/mol[/tex]

The activation energy Ea for this reaction is 22689.8 J/mol

Answer:

[tex]r=-k[H_2][O_2]^{1/2}[/tex]

Explanation:

Hello!

In this case, according to the chemical reaction:

H2 + 1/2  O2 --> H2O​

Since both hydrogen and oxygen are the reactants and the rate laws are written in terms of the concentration of reactants and the rate constant, we obtain:

[tex]r=-k[H_2][O_2]^{1/2}[/tex]

Whereas the negative sign represents the consumption of those reactants and the power 1/2 the stoichiometric coefficient of oxygen in the reaction.

Best regards!

Answer:

5. higher

6. shifted down

7. closer together  

8. increase its wave length

Explanation:

Answer and Explanation:

(a) When lithium bromide (LiBr) solution is mixed with a solution of lead (II) nitrate (Pb(NO₃)₂), lithium nitrate (LiNO₃) and lead (II) bromide (PbBr₂) are formed, according to the following molecular equation:

2LiBr(aq) + Pb(NO₃)₂(aq) → 2LiNO₃(aq) + PbBr₂(s) ↓

As the product PbBr₂ is an insoluble solid, it precipitates (↓).

(b) The total ionic equation is written with all ions of the reaction - no matter if they participate in the precipitate formation or not:

2Li⁺(aq) + 2Br⁻(aq) + Pb²⁺(aq) + 2NO₃⁻(aq) → 2Li⁺(aq) + 2NO₃⁻(aq) + PbBr₂(s)

(c) The net ionic equation is written including only the ions which participate in the precipitate formation. In this case, the precipitate is PbBr₂, and it is formed by Pb²⁺ and Br⁻ ions:

Pb²⁺(aq) + 2Br⁻(aq) → PbBr₂(s)

(d) The spectator ions are those which do not participate in the formation of the precipitate. From the total ionic equation, we can see that Li⁺ and NO₃⁻ ions are repeated on both sides of the equation, so they are redundant. Thus, the spectator ions are Li⁺ and NO₃⁻ ions.

(e) To identify the limiting reactant, we first calculate the moles of each compound as the product of the solution concentration and volume:

For LiBr:

C = 1.00 M = 1 mol/L

V = 100.0 mL x 1 L/1000 mL = 0.1 L

moles of LiBr = 0.1 L x 1.00 mol/L = 0.1 mol

The same for Pb(NO₃)₂:

C = 1.00 M = 1 mol/L

V = 100.0 mL x 1 L/1000 mL = 0.1 L

moles of Pb(NO₃)₂  = 0.1 L x 1.00 mol/L = 0.1 mol

From the total ionic equation, we can see that 2 mol of LiBr reacts with 1 mol of Pb(NO₃)₂ to give 1 mol of PbBr₂ (solid product). The stoichiometric molar ratio is 2 mol LiBr/1 mol Pb(NO₃)₂ and we have 0.1 mol of each reactant (0.1 mol LiBr/0.1 mol Pb(NO₃)₂= 1). As 2 mol LiBr/mol Pb(NO₃)₂ > 1 mol LiBr/mol Pb(NO₃)₂, LiBr is the limiting reactant.

(f) From the total ionic equation, we know that 2 moles of LiBr produce 1 mol of PbBr₂. To determine the mass of solid product (PbBr₂) formed, we first multiply the stoichiometric ratio (1 mol PbBr₂/2 mol LiBr) by the actual number of moles of limiting reactant we have (0.1 mol):

moles of PbBr₂ = 0.1 mol LiBr x (1 mol PbBr₂/2 mol LiBr) = 0.05 mol PbBr₂

Finally, we convert the moles of PbBr₂ to gram by using the molar mass of the compound:

Molar mass PbBr₂ = 207.2 g/mol + (2 x 79.9 g/mol) = 367 g/mol

grams of PbBr₂ = 0.05 mol x 367 g/mol = 18.35 g

Answer:

there are about 11.2 liters

Answer:

ionic

Explanation:

the bonds that hold magnesium and oxygen together are formed between atoms that give electrons

Answer:

Beta Rays

Beta Rays are not Electromagnetic Waves

Beta rays also known as beta radiation is obtained through the emission of an electron. Beta rays are not electromagnetic waves because they are charged particles and are capable of getting deflected by the magnetic field.

Answer:

Explanation:

mass fraction N₂ : He : CH₄ : C₂H₆ : : 15 : 5 : 60 : 20

mole fraction  N₂ : He : CH₄ : C₂H₆ : : 15/28 : 5/4 : 60/16 : 20/30

mole fraction  N₂ : He : CH₄ : C₂H₆ : : .5357  : 1.25 : 3.75 : .67

Total mole fractions = .5357 + 1.25 + 3.75 + 0.67 = 6.2057

mole fraction of N₂ =  .5357 / 6.2057 = .0877

mole fraction of He = 1.25 / 6.2057 = .20

mole fraction of CH₄ = 3.75 / 6.2057 = .6043

mole fraction of C₂H₆ = .67 / 6.2057 = .108

Partial pressure = total pressure x mole fraction

Partial pressure of N₂ = 1200 kPa  x .0877 = 105.24 kPa

Partial pressure of He = 1200 kPa  x .20  = 240 kPa

Partial pressure of CH₄ = 1200 kPa  x  .6043  = 725.16 kPa

Partial pressure of C₂H₆ = 1200 kPa  x .108    = 129.6 kPa

Answer:

0.64 mol

Explanation:

moles=mass/molar mass

n= 75/(39+14+4×16)

n=75/117

n = 0.64mol

Answer:

See explanation below

Explanation:

Since question 3 is not here, I will answer based on a general perspective.

The dosage of most antibiotics and drugs generally are prescribed without considering the weight of adults. Unlike children that are given dosages based on their weight.

The weight of adults is not considered because the extent to which they weigh is majorly as a result of their adipose (fat) tissue. And the adipose tissue does not determine the tolerance level of drugs. So an adult weighing 200kg and another weighing 50kg will be able to tolerate the same dosage of medications.

Because the adults are adults with fully developed organs, their weight does not matter when prescriptions are made.

Answer:

[tex][NO]=\frac{k_{-1}}{k_1} [N_2O_2][/tex]

Explanation:

Hello!

In this case, since the reaction may be assumed in chemical equilibrium, we can write up the rate law as shown below:

[tex]r=-k_1[NO]+k_{-1}[N_2O_2][/tex]

However, since the rate of reaction at equilibrium is zero, due to the fact that the concentrations remains the same, we can write:

[tex]0=-k_1[NO]+k_{-1}[N_2O_2][/tex]

Which can be also written as:

[tex]k_1[NO]=k_{-1}[N_2O_2][/tex]

Then, we solve for the concentration of NO to obtain:

[tex][NO]=\frac{k_{-1}}{k_1} [N_2O_2][/tex]

Best regards!