A block of aluminum is dropped into a graduated cylinder with an initial volume of water at 75mL and the volumes rises to 90mL. If the block has a mass of 40.5 g what is its density ?

Answer:

5.0 x 10⁹ years.

Explanation:

k = ln(2)/(t1/2) = 0.693/(t1/2).

Where, k is the rate constant of the reaction.

t1/2 is the half-life of the reaction.

∴ k =0.693/(t1/2) = 0.693/(1.251 × 10⁹ years) = 5.54 x 10⁻¹⁰ year⁻¹.

kt = ln([A₀]/[A]),

where, k is the rate constant of the reaction (k = 5.54 x 10⁻¹⁰ year⁻¹).

t is the time of the reaction (t = ??? year).

[A₀] is the initial concentration of (K-40) ([A₀] = 100%).

[A] is the remaining concentration of (K-40) ([A] = 6.25%).

∴ (5.54 x 10⁻¹⁰ year⁻¹)(t) = ln((100%)/( 6.25%))

∴ (5.54 x 10⁻¹⁰ year⁻¹)(t) = 2.77.

∴ t = 2.77/(5.54 x 10⁻¹⁰ year⁻¹) = 5.0 x 10⁹ years.

Answer:

[tex]\boxed{4.99 \times10^{9} \text{ y}}[/tex]

Explanation:

The half-life of potassium-40 (1.248 ×10⁹ y) is the time it takes for half of it to decay.  

After one half-life, half (50 %) of the original amount will remain.  

After a second half-life, half of that amount (25 %) will remain, and so on.  

We can construct a table as follows:  

[tex]\begin{array}{cccc}\textbf{No. of} & &\textbf{Fraction} &\textbf{Percent}\\ \textbf{Half-lives} & \textbf{t/(10$^{9}$ y}) &\textbf{Remaining} &\textbf{Remaining}\\0 & 0 & 1 & 100\\\\1 & 1.248 & \dfrac{1}{2} & 50\\\\2 & 2.496 & \dfrac{1}{4} & 25\\\\3 & 3.744 & \dfrac{1}{8} & 12.5\\\\4 & 4.992 & \dfrac{1}{16} & 6.25\\\\5 & 6.240 & \dfrac{1}{32} & 3.125\\\\\end{array}[/tex]

We see that after four half-lives, ¹/₁₆ or 6.25 % of the original mass remains.

Conversely, if 6.25 % of the sample remains, the age of the sample must be four half-lives.

[tex]\text{Age of rock} = 4 \times 1.248 \times 10^{9}\text{ y}= \boxed{\mathbf{4.99 \times 10^{9}} \textbf{ y}}[/tex]

Answer:

250 gm

Explanation:

Latent heat of ice=80 calories /g

ice=20000÷80=250 gm

Answer: OA is a balanced equation.

Explanation: For an equation to be balanced, the number of atoms and the total charge of each element in the reaction, of the product and reactant side must be the same.

Considering OA; 6 atoms of nitrogen is present in the reactant side. Shifting to the product side, 6 atoms of nitrogen is also present. Taking the other element in the reaction into account, the number of atoms of each element balances on both sides.

ANSWER:

The correct answer is OA. 2NH3 (g) + 3Mg (s) →3H2 (g) + Mg3N2 (s)

The Equation; 2NH3 (g) + 3Mg (s) →3H2 (g) + Mg3N2 (s), is a balanced chemical equation.

FURTHER EXPLANATION;

According to the law of conservation of mass, all chemical equations should be written such that the mass of the reactants is equal to the mass of the products.

This is done by balancing the chemical equation.

Balancing of chemical equations is a try and error method that makes sure the number of atoms of each element in a chemical equation are equal on the side of the reactants and that of products.

The equation; 2NH3 (g) + 3Mg (s) →3H2 (g) + Mg3N2 is said to be balanced since the number of atoms of each element are equal on both side of the equation.

That is; 2 atoms of nitrogen, 6 atoms of hydrogen and 3 atoms of magnesium on both side of the equation.

Choice OB is incorrect because, the equation 4NH3 (g) + Mg(s)* - H2(g) + Mg3N2 (s) is not balanced as the number of nitrogen atoms and that of hydrogen atoms are not equal on both side of the equation.(4 nitrogen atoms on the reactant side and 2 nitrogen atoms on the product side, 12 hydrogen atoms on the reactant side and 2 hydrogen atoms on the product side).

Choice OC is incorrect because, the equation, NH3 (g) + Mg (s) - H2 (g) + Mg3N2 (s) is not balanced as the number of nitrogen atoms, magnesium atoms and that of hydrogen atoms are not equal on both side of the equation.(1 nitrogen atom on the reactant side and 2 nitrogen atoms on the product side, 3 hydrogen atoms on the reactant side and 2 hydrogen atoms on the product side, 1 magnesium atom on the reactant side and 3 magnesium atom on the product side).

Choice OD is incorrect because, the equation Ca (s) + 02 (9) - 2Cao (s) is not balanced as the number calcium atoms is not the same on both side of the equation, 1 calcium atom on the reactant side and 2 calcium atoms on the product side.

Mg = 0

H =+1

Cl= -1

Mg= +2

Cl=-1

H= 0

Answer:

B,C,D,E

Explanation:

Edge

Answer:

second one

Explanation:

Hello There!

0.0045 Inches are larger than centimeters.

Answer:

B. Changes in energy in systems.

Explanation:

Thermodynamics is a branch of physics which deals with heat and temperature in relation to energy work radiation and characteristics of matter.

This field studies the causes of energy changes and the effects of energy changes to chemical and  physical systems.

Thermodynamics relates B) changes in energy in systems.

Thermodynamics is the part of material science that manages warmth and temperature, and their connection to energy, work, radiation, and properties of issue. The conduct of these amounts is administered by the four laws of thermodynamics which pass on a quantitative depiction utilizing quantifiable naturally visible physical amounts, yet might be clarified as far as tiny constituents by factual mechanics.

Thermodynamics applies to a wide assortment of subjects in science and building, particularly physical science, concoction designing and mechanical designing, yet in addition in fields as intricate as meteorology.

Answer:

The correct answer is "decreased genetic variation".

Explanation:

By introducing a new pesticide into the habitat of a beetle population what happens is that there will be a decrease in the genetic variation in this population. This is due to the harmful effect that pesticides have on insects and other living beings.

Have a nice day!

A new pesticide has been introduced to the habitat of this population of beetles. The effect of this environmental change is decreased genetic variation and the correct option is option 1.

Pesticides are chemical substances that are meant to kill pests. In general, a pesticide is a chemical or a biological agent such as a virus, bacterium, antimicrobial, or disinfectant that deters, incapacitates, kills, pests.

By their nature, pesticides are potentially toxic to other organisms, including humans, and need to be used safely and disposed of properly. They are among the leading causes of death by self-poisoning, and this burden is felt disproportionately in low- and middle-income countries.

Therefore, A new pesticide has been introduced to the habitat of this population of beetles. The effect of this environmental change is decreased genetic variation and the correct option is option 1.

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Answer:

GAS

Explanation:

Answer:

Gas

Explanation:

The gaseous state of matter is highly compressible. According to the kinetic theory of matter, in the gaseous state, gas molecules largely move independent of each other and experience very little intermolecular forces between them.

Gases are abundant in the atmosphere near the earth's surface.

Answer:

69.8 %.

Explanation:

2Na + Cl2 = 2NaCl

Using Relative Atomic Masses:

2*22.99 g sodium should produce  2*(22.99 + 35.45) =   116.88 g of sodium chloride

So 5.75 g Na should give 116.88 * 5.75 / 2*22.99 g = 14.62 g NaCl

% yield = 10.2 / 14.62 = 69.8%.

2Na + Cl2 = 2NaCl

Using Relative Atomic Masses:

2×22.99 g sodium should produce  2×(22.99 + 35.45) =   116.88 g of sodium chloride

So 5.75 g Na should give 116.88 ×5.75 / 2×22.99 g = 14.62 g NaCl

percentage yield = 10.2 / 14.62 = 69.8%.

Sodium chloride is the chemical name for salt. Sodium is an electrolyte that regulates the amount of water in your body. Sodium also plays a part in nerve impulses and muscle contractions.

Sodium chloride is an essential nutrient and is used in healthcare to help prevent patients from becoming dehydrated. It is used as a food preservative and as a seasoning to enhance flavor.

Sodium chloride is also used in manufacturing to make plastics and other products. It is also used to de-ice roads and sidewalks.

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Answer:

A. have subjects wear the shoes in an experimental trial to see if symptoms improve.

Answer: Option A

Explanation:

When the team of engineers decided to design a footwear that will help the people suffering from painful foot condition that is caused by footwear.

There are many steps in designing such a footwear that is helpful in treating this problem. First of all they will look the other footwear available in the market and the problem that is not being solved by the available option.

They will do research and study a bit of orthopedics to get more knowledge about the bones and shoes.

They will also estimate the cost of shoes. But they will not wait to see if the symptoms improve because it is the feedback step of the experiment.

The ideal gas law states: [tex]PV=nRT[/tex]

If we put in the data.

[tex]

1\cdot7=n\cdot8.31\cdot294 \\

n=\boxed{2.865\cdot10^{-3}mol}=\boxed{2.865mmol}

[/tex]

Hope this helps.

r3t40

Using the ideal gas law PV = nRT, the number of moles of air in a 3 L container at 1 atm and 294 K is calculated to be approximately 0.124 moles.

Calculating Moles of Air Using the Ideal Gas Law

To find the number of moles of air in a 3 L container at 1 atm pressure and 294 K, we can use the ideal gas law, PV = nRT. We are given the following values: P (pressure) = 1 atm, V (volume) = 3 L, T (temperature) = 294 K. We can use R (the ideal gas constant) = 0.08206 L-atm/mol-K, which is appropriate for the units provided.

Step-by-step solution:

After doing the math, we find that the number of moles n of air is approximately 0.124 moles.

Answer:

a) 7.0.

b) Nickel sulfate hepta hydrate.

c) 280.83 g/mol.

d) 44.9%.

Explanation:

a) What is the formula of the hydrate?

The mass of the hydrated sample (NiSO₄.xH₂O) = 5.0 g,

The mass of the anhydrous salt (NiSO₄) = 2.755 g,

The mass of water = 5.0 g - 2.755 g = 2.245 g.

∴ no. of moles of water = mass/molar mass = (2.245 g)/(18.0 g/mol) = 0.1247 mol.

∴ no. of moles of anhydrous salt (NiSO₄) = mass/molar mass = (2.755 g)/(154.75 g/mol) = 0.0178 mol.

∴ water of crystallization in the sample (x) = no. of moles of water/no. of moles of anhydrous salt (NiSO₄) = (0.1247 mol)/(0.0178 mol) = 7.0.

b) What is the full chemical name for the hydrate?

The name of the salt (NiSO₄.7H₂O) is Nickel sulfate hepta hydrate.

c) What is the molar mass of the hydrate?

(NiSO₄.7H₂O)

The molar mass = molar mass of NiSO₄ + 7(molar mass of H₂O) = (154.75 g/mol) + 7(18.0 g/mol) = 280.83 g/mol.

d) What is the mass % of water in the hydrate?

The mass % of water = (mass of water)/(mass of hydrated sample) x 100 = (2.245 g)/(5.0 g) x 100 = 44.9%.

Answer:

0.009 mol.

Explanation:

M = (no. of moles of acetic acid)/(Volume of the solution (L)).

M = 0.9 M, Volume of the solution = 10.0 mL = 0.01 L.

∴ no. of moles of acetic acid = (M)(Volume of the solution (L)) = (0.9 M)(0.01 L) = 0.009 mol.

Answer:

The number of acetic acid moles is 0.0090 in 10 ml of the solution​.

Explanation:

[tex]Molarity=\frac{Moles}{Volume (L)}[/tex]

Let the moles acetic acid in vinegar be n.

Molarity of the vinegar solution = 0.90 M

Volume of the vinegar solution = 10 mL = 0.010 L

1 mL = 0.001 L

[tex]0.90M=\frac{n}{0.010 L}[/tex]

[tex]n=0.90 M\times 0.010 L=0.0090 mol[/tex]

The number of acetic acid moles is 0.0090 in 10 ml of the solution​.

Answer:

Solution G has 100 times more hydroxide ions than Solution F.

Explanation:

∵ pH + pOH = 14.

∴ pOH = 14 - pH.

pOH = 14 - pH = 14 - 11 = 3.

∵ pOH = -log[OH⁻] = 3.

∴ [OH⁻] = 0.001 M.

pOH = 14 - pH = 14 - 13 = 1.

∵ pOH = -log[OH⁻] = 1.

∴ [OH⁻] = 0.1 M.

∴ [OH⁻] of solution G / [OH⁻] of solution F = (0.1)/(0.001) = 100.

So, Solution G has 100 times more hydroxide ions than Solution F.

Answer:

Q(total) = 283Kj

Explanation:

5 Heat Transitions …

Specific Heats => c(s) = 0.50cal/g∙⁰C,  c(l) = 1.0 cal/g∙⁰C, c(g) = 0.48 cal/g∙⁰C

Phase Transition Constants => ΔHᵪ = Heat of Fusion = 80 cal/g; ΔHᵥ = Heat of Vaporization = 540cal/g

Note => Phase change regions => no temp. change occurs when 2 phases are in contact (melting and evaporation). Only when single phase substance exists (s, l or g) does temperature change occur. See heating curve for water diagram. The increasing slopes are temperature change regions and heat flow is given by Q =mcΔT. The horizontal slopes are phase changes ( melting & evaporation) and heat flow for each of those regions is given by Q = m·ΔH. Each transition energy is calculated individually (see below) and added to obtain the total heat flow needed.

Q = mcΔT for temperature change regions of the heating curve (single phase only)

Q = m∙ΔH for phase transition regions of the heating curve (2 phases in contact)

Solid (ice) => Melting Pt  => Q(s) = mcΔT = (90.5g)(0.50cal/g∙⁰C)(11⁰C) = 478 cal

Melting (s/l) => Liquid (water) =>   Q(s/l) = m∙ΔHᵪ = (90.5g)(80cal/g) = 7240 cal

Liquid (water) => Boiling Pt => Q(l) = mcΔT = (90.5g)(1.0cal/g∙⁰C)(100⁰C) = 9050 cal

Boiling (l/g) => Gas (steam) => Q(l/g) = m∙ΔHᵥ = (90.5g)(540cal/g) = 48,870 cal

Gas (steam) => Steam @ 145⁰C => Q(g = mcΔT = (90.5g)(0.48cal/g∙⁰C)(45⁰C) = 2036 cal

Total Heat Transfer (Qᵤ) = Q(s) + Q(s/l) + Q(l) + Q(l/g) + Q(g)  

                                 = 478cal +7240cal + 9050 cal + 48,870cal + 2036cal

                                 = 67,674 cal x 4.184 j/cal = 283,148 joules = 283 Kj

Answer:

b. 2 g/mL

Explanation:

Density=mass/volume.

so: D=10g/5mL

Density=2g/mL

Answer:

The correct answer is option b.

Explanation:

To calculate density of a substance, we use the equation:

[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]

We are given:

Mass of an object = 10 g

Volume of an object  = 5 mL

Density of an object = d

Putting values in above equation, we get:

[tex]d=\frac{10 g}{5 mL}=2 g/mL[/tex]

2 g/mL is the density of an object that has a mass of 10 g and a volume of 5 mL.

Answer:

The approximate molar mass of NaOH is 40 g/mol. You have 4 g NaOH.

No. of moles of NaOH is given by

n=(Given mass)/(Molar mass)

= 4/40 = 0.1 mol

1 mol has 6.022 × 10^23 molecules.

Thus, 0.1 mol has 6.022 × 10^23 × 0.1 molecules i.e. 6.022 × 10^22 molecules.

Explanation:

Final answer:

There are 12 atoms in 4 molecules of NaOH.

Explanation:

To determine the number of atoms in 4 molecules of NaOH, we must first understand the chemical formula of NaOH. NaOH consists of one sodium atom (Na), one oxygen atom (O), and one hydrogen atom (H). To calculate the total number of atoms, we multiply the number of molecules (4) by the number of atoms in each molecule (3). Therefore, there are 12 atoms in 4 molecules of NaOH.

Answer:

2. B.

Explanation:

Answer:

2. B on EDG 2020

Explanation:

Got it Right :)

Answer:

Explanation:

The combined gas law is also known as general gas law and it is the reduction of the ideal gas equation. In the combined gas law, we assume that n= 1

              From           PV=nRT

                              [tex]\frac{PV}{T}[/tex] = R (constant) if n= 1

      ∴ [tex]\frac{P_{1} V_{1} }{T_{1} }[/tex] =  [tex]\frac{P_{2} V_{2} }{T_{2} }[/tex] =  [tex]\frac{P_{n} V_{n} }{T_{n} }[/tex]

Answer: Both!

Explanation:

Answer:

Dependent variable

Explanation:

Answer:

A variable

Explanation:

A variable is data that changes, two examples are an independent variable and a dependent variable.

Answer:

The temperatures of the objects must be different

Explanation:

if heat is flowing between two objects, then the objects must be at different temperatures.

Answer:

The have to different temperature

Explanation:

Answer: A

Explanation: Boiling point increases with the rise of electrons.

Answer:

Not sure what the answer is, but it's not A.

Explanation:

Submitted the problem and A was incorrect.

Answer:

13.28 mol.

Explanation:

where, P is the pressure of the gas in atm (P = 1.32 atm).

V is the volume of the gas in L (V = 242.0 L).

n is the no. of moles of the gas in mol (n = ??? mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K).

T is the temperature of the gas in K (T = 20.0° + 273 = 293.0 K).

∴ n = PV/RT = (1.32 atm)(242.0 L)/(0.0821 L.atm/mol.K)(293.0 K) = 13.28 mol.

Answer:

Lithium batteries are well-known for powering our phones and the latest lightweight laptop computers.

Lithium batteries are popular because they are lightweight, provide a stable voltage, are long-lasting, and are capable of delivering a high amount of current, making them suitable for a variety of applications from consumer electronics to electric vehicles and medical devices.

Lithium batteries are among the most popular types of rechargeable batteries used today. They are commonly found in a wide range of portable electronic devices. Here are some key details about their use and why they are so popular:

Answer:

1. There are many branches of chemistry or chemistry disciplines. The five main branches are organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry, and biochemistry.

2. 25mg

The question regarding the percentage purity of glucose falls under the domain of analytical chemistry, a branch of chemistry focused on analyzing substances to ascertain their composition and purity. It involves calculating the ratio of the pure substance's mass to the sample's total mass and converting this into a percentage.

The question about identifying the percentage purity of glucose pertains to the branch of chemistry known as analytical chemistry. This field is crucial for quantitatively and qualitatively analyzing substances to determine their composition and purity. To find the percentage purity of a sample, one would typically use the formula:

%purity = (mass of compound / mass of sample) × 100

For instance, if you're analyzing glucose, you'll first need to determine the total mass of the glucose sample you're evaluating. After that, you conduct an experiment or analysis to ascertain the mass of pure glucose within that sample. Once you have both values, you substitute them into the equation to calculate the percent purity of the glucose. This allows chemists to ensure that the concentration of glucose or any other substance is within the required specifications for its intended use, whether that be for consumption, industrial applications, or research.

Such analysis is vital for ensuring the safety and effectiveness of products, maintaining quality control, and complying with legal standards for purity and composition.

Answer:

The suns mass affects the planets in the solar system because the grater the mas the stronger the gravitaional pull so the saster the planet orbits the sun.

Explanation:

Suns mass directly affected the position of planets in the solar system.

If the mass of the Sun is increased, the Sun would exert a stronger gravitational force on materials present around it. This change in mass of sun would disturb the orbits of all of the planets, pulling them closer to it.

So we can conclude that suns mass directly affected the position of planets in the solar system.

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Answer:

The ions are now combining to reduce their concentrations.

Explanation:

PbCl₂(s) ⇄ Pb²⁺(aq) + 2Cl⁻(aq),

It is mentioned that the value of Ksp is 1.8 × 10⁻².

∵ The solubility product is lower for this reaction that means the ions produced are getting combined.

∴ Resulting in reducing the concentration of the ions and increasing the formation of the solid lead chloride.

Answer:

The ions are now combining to reduce their concentrations.

Explanation:

Answer:

The options are missing, so I will answer the question in a general manner.

This group of elements includes the alkali metals, alkaline earth metals, transition metals, basic metals, lanthanides and actinides. Depending on conditions, elements belonging to the metalloid group may behave like metals.  So, if you want to know if an element is a metal, just found it in the periodic table.

When bonding with nonmetals in ionic compounds, they are converted into cations. When bonding together they make metallic compounds. When multiple metals bound they form alloys (these can include nonmetals too).

Nuclear fission is a nuclear reaction where a nucleus absorbs a neutron and splits into two smaller nuclei, releasing energy and more neutrons, which can cause a chain reaction. It's used in nuclear reactors and nuclear weapons.

Nuclear fission is the process in which a nucleus absorbs a neutron and splits into two lighter nuclei, known as fission fragments, releasing a significant amount of energy. This reaction is exothermic, meaning it releases energy in the form of heat, gamma rays, and the kinetic energy of additional neutrons.

These free neutrons may go on to induce fission in other nuclei, creating a chain reaction. A critical aspect of fission is that a minimum amount of fissile material, known as the critical mass, is necessary for a sustained chain reaction to occur. Therefore, the correct option that describes this process is 'A nucleus collides with a neutron and splits, releasing energy.'

The enormous energy release from fission makes it the foundational principle behind nuclear reactors and nuclear weapons. The fission of heavy elements like uranium or plutonium is harnessed as a heat source in nuclear power plants to produce electricity or to drive explosive reactions in atomic bombs.

Answer:

D : Nuclei combine to form a heavier nucleus, releasing energy.

Explanation:

Nuclear fusion is a process by which two or more atomic nuclei combine to form one or more different atomic nuclei and subatomic particles. The nuclei usually involved are deuterium and tritium, which are hydrogen variants. The difference in mass between the reactants and products is manifested as either the release or absorption of energy. Fusion reactions take place in a state of matter called plasma, which is a hot, charged gas made of positive ions and free-moving electrons. Fusion reactions release massive amounts of energy, and this is the same process that powers the sun