How many significant digits are in 15.000?

Answer:

1.1328 g left after 15.6 years

Explanation:

First we need to find, that how many times it decays: 15.6 ÷ 2.60 = 6 times

Then we know the formula: mass of original ÷ 2^n = remaining mass.

                                           :     72.5   ÷   2^6 = 1.1328 g left.

Answer:

remaining mass = 1.13 grams (3-sig figs)

Explanation:

All radioactive decay follows 1st order kinetics and is defined by the expression ...

A = A₀e^⁻kt

A = final mass activity

A₀ = initial mass activity

k = rate constant = 0.693/t(half-life) = 0.693/2.60 yrs = 0.2665 yrs⁻¹

t = time of decay = 15.6 yrs

A = (72.5 g)(e^[-(0.2665 yrs⁻¹)(15.6yrs)] = 72.5 grams x 0.0156

= 1.13381331 grams (calc. ans.) ≅ 1.13 grams (3 sig figs)

Answer:

synthetic material is material made by humans through chemical synthesis and natural substances. Natural materials come from the natural environment, and have been changed very little. A synthetic material is a material that is obtained from a natural material which has undergone a chemical reaction in a laboratory or factory. Both natural and synthetic materials are found in products you use every day.

Explanation:

Answer:

Physical Properties

Explanation:

PHYSICAL PROPERTY

Answer:

phycical propertys

Explanation:

jut took the test got it right

Answer:

a

Explanation:

pls sdame

The half-life of Po-210 is 140 days. If the initial mass of the sample is 5 kg, 3.5g will remain after 280 days.

Chemical kinetics is a subfield of physical chemistry that studies the speeds of chemical processes. The rate of the reaction may be used to classify it as quick, moderate, or sluggish. Reaction mechanism also enables us to study the effects of temperature and catalyst on reaction rate and rate constant. It informs us about reaction processes and enables us to apply particular rate constants to certain mechanistic stages.

The rate law for first order kinetics is

K=(2.303/T)×log(a/a-x)

half life=0.693/K

Where

k - rate constant

t - time passed by the sample

a - initial amount of the reactant

a-x - amount left after the decay process

K=0.693/half life

K=0.693/140

=0.086

0.086=(2.303/ 280)×log( 5 /a-x)

0.086=0.07×log( 136/a-x)

1.22=log( 136/a-x)

136/a-x=16.5

a-x=3.5g

Therefore, 3.5g will be left after 280 days.

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If we add more magnesium to the reaction, the reaction speed will increase.

The chemical reaction shown is a single-displacement reaction, also known as a single-replacement reaction. In this type of reaction, one element replaces another element in a molecule, producing a new compound and a different element.

In the given reaction, magnesium (Mg) reacts with sulfuric acid (H₂SO₄) to produce magnesium sulphate (MgSO₄) and hydrogen gas (H₂). This can be represented by the following balanced chemical equation:

Mg + H₂SO₄ → MgSO₄ + H₂

This is because the amount of reactant determines the number of reactions that can occur. If the amount of magnesium is increased, more magnesium atoms are available for the reaction with sulfuric acid, leading to a higher rate of reaction.

However, this increase in reaction rate is only valid up to a certain point, after which further addition of magnesium will not lead to an increase in rate of reaction. This is because other factors such as the concentration of sulfuric acid and the temperature of the reaction may become limiting factors that can no longer be compensated by adding more magnesium.

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At equilibrium, the number of moles of \(Cl_2\) (g) will be 0.2025 mol.

1: Write the balanced chemical equation:

\(C_O\)(g) + \(Cl_2\)(g) ⟶ \(C_OCl_2\)(g)

2: Set up an ICE table to track the changes in moles of the substances involved in the reaction.

Initial:

\(C_O\)(g) = 0.3500 mol

\(Cl_2\)(g) = 0.05500 mol

\(C_OCl_2\)(g) = 0 mol

Change:

\(C_O\)(g) = -x

\(Cl_2\)(g) = -x

\(C_OCl_2\)(g) = +x

Equilibrium:

\(C_O\)(g) = 0.3500 - x mol

\(Cl_2\)(g) = 0.05500 - x mol

\(C_OCl_2\)(g) = x mol

3: Write the expression for the equilibrium constant (Kc) using the concentrations of the species involved:

Kc = [\(C_OCl_2\)(g)] / [\(C_O\)(g)] * [\(Cl_2\)(g)]

4: Substitute the given equilibrium constant (Kc) value into the expression:

1.2 x \(10^3\) = x / (0.3500 - x) * (0.05500 - x)

5: Solve the equation for x. Rearrange the equation to obtain a quadratic equation:

1.2 x \(10^3\) * (0.3500 - x) * (0.05500 - x) = x

6: Simplify and solve the quadratic equation. This can be done by multiplying out the terms, rearranging the equation to standard quadratic form, and then using the quadratic formula.

7: After solving the quadratic equation, you will find two possible values for x. However, since the number of moles cannot be negative, we discard the negative solution.

8: The positive value of x represents the number of moles of \(Cl_2\)(g) at equilibrium. Substitute the value of x into the expression for \(Cl_2\)(g):

\(Cl_2\)(g) = 0.05500 - x

9: Calculate the value of \(Cl_2\)(g) at equilibrium:

\(Cl_2\)(g) = 0.05500 - x

\(Cl_2\)(g) = 0.05500 - (positive value of x)

10: Calculate the final value of \(Cl_2\) (g) at equilibrium to get the answer.

Therefore, at equilibrium, the number of moles of \(Cl_2\) (g) will be 0.2025 mol.

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CO₂ have a higher boiling point than CH₄ when they both possess dispersion forces because CO₂ consists of polar bonds between carbon and oxygen.

Intermolecular forces determine bulk properties, such as the melting points of solids and the boiling points of liquids.

Liquids boil when the molecules have enough thermal energy to overcome the intermolecular attractive forces that hold them together, thereby forming bubbles of vapor within the liquid.

CO₂ have a higher boiling point than CH₄ when they both possess dispersion forces because CO₂ consists of polar bonds between carbon and oxygen. The polarity increases the boiling point of the molecule.

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a. The calories increase by 9:00 whenever the running speed goes up by two. so so if a dog were running at 10 km/h it would be 54 calories burnt

b. they are multiplied by 9

Answer :Hydrophobicity is measured in terms of the contact angle of the water drops to the surface of textiles

Explanation:

The dependent variable in the information regarding the cattles is D. Temperature of Cattle.

A dependent variable is one that is altered as a result of the modification of an independent variable. Your independent variable "depends" on the outcome you're interested in measuring. Dependent variables are also known as response variables in statistics (they respond to a change in another variable)

It is something on which other elements depend. For instance, a test result might be a dependent variable because it depends on a number of variables, including how much you studied.

In this case, one will measure the temperature of the cattle to see whether or not it works. This is the dependent variable.

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You are managing a large lot of cattle. A pharmaceutical company wants you to try a new antibiotic to treat Shipping Fever in newly arrived cattle. The company claims that it is less expensive and more effective than the current antibiotic you are using. You will measure the temperature of the cattle to see whether or not it works. WHAT IS THE DEPENDENT VARIABLE (DV)?

Type of cow

Antibiotic

No Antibiotic

Temperature of Cattle

The measured volume of hydrogen gas will be too high.

The volume of hydrogen is measured by collecting the gas over water. The volume of the gas is measured as the volume of water displaced by the gas in an inverted container.

When air leaks into the graduated cylinder, more volume of water is displaced hence a higher volume of hydrogen gas is measured.

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Answer:

11

Explanation:

so that is 20\100× 55 that gives you 11

thanks so please follow me

3.9g Oxygen

Explanation:

The molecular mass of KClO₃=122.55g/mol

The molecular mass of KCl=74.55g/mol

245.1g KClO3 produces 192 g of oxygen gas.

Therefore,5g KClO₃ gives=192*5/245.1=3.9g oxygen

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Answer:

Br-CH2-CH(CH3)2-C(Cl)H-CH(CH3)2-CHO

Explanation:

The molecule has a total of 14 carbon atoms, 13 hydrogen atoms, and 1 bromine atom. The carbon atoms are arranged in a chain with a methyl group attached to the second carbon atom, a chlorine atom attached to the third carbon atom, and two methyl groups attached to the fourth carbon atom. The fifth carbon atom has a carbonyl group attached to it.

The molecule is an aldehyde, which means that it has a carbonyl group (C=O) at the end of the chain. The carbonyl group is polar, and the oxygen atom has a partial negative charge. The hydrogen atom has a partial positive charge. This polarity makes the aldehyde group susceptible to nucleophilic attack.

The bromine and chlorine atoms are both electrophilic, which means that they have a partial positive charge. This makes them susceptible to nucleophilic attack.

The methyl groups are non-polar and do not have any significant reactivity.

The molecule is a chiral molecule, which means that it has a mirror image that is not superimposable on itself. This is because the carbon atom with the carbonyl group is attached to four different groups.

The molecule is a liquid at room temperature and has a strong odor. It is used in a variety of products, including perfumes, flavorings, and plastics.

Answer:

There is a connection between the ocean and the atmosphere (they work together to move heat and fresh water across the globe) . Heat can be  transferred between the surface of a sea or ocean and the atmosphere through ;

Explanation:

This is due to the fact that a substance's chemical qualities, such as its molecular form, polarity, and functional groups, govern how it behaves and interacts with other substances.

By illustrating the spatial arrangement of atoms and chemical bonds within the molecule, chemical structure establishes the molecular geometry of a compound. In doing so, chemists are given a crucial visual depiction of a chemical formula.

In a chemical reaction, reactants come into contact with one another, atoms in the reactants break their connections with one another, and then the atoms reorganise and form new bonds to create the products.

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Thomas Edison is the answer...no a

Na>Mg>Zn>Fe is the proper sequence of reactivity. Caesium is both the most electropositive element and the most reactive metal in the periodic table.

According to their reactivity, metals are arranged as follows: K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Ag > Au. In light of this, the proper sequence is Fe > Ni > Sn > Pb > H > Cu > Au.

A chart listing metals in decreasing order of reactivity is called the metals reactivity series. A metal generally reacts with other chemicals more forcefully the more reactive it is. the easier it is for positive ions to form when losing electrons (cations)

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Answer:

D - synapse

Explanation:

Synapse, also called neuronal junction, the site of transmission of electric nerve impulses between two nerve cells (neurons) or between a neuron and a gland or muscle cell (effector). A synaptic connection between a neuron and a muscle cell is called a neuromuscular junction.

Answer:

Yes

Explanation:

By forcing the atoms into a new configuration is possible.

The addition of new atoms around the atom will change the electronic geometry of the atoms. The addition of electron-accepting or donating atoms will result in a change in configuration. The configuration change will result in the change in the hybridization of the atom, and it will acquire a new shape. The geometry of the molecule changes and it will acquire the lowest energy state.

This suggests that atoms in real molecules are present in the flexible state of configuration, and are at least energy, The change in the surrounding changes the configuration of the atoms, and are easily configured.

Answer:C I think

Explanation:

Hope this helps:)

Answer:

it would be 1

Explanation:

Answer:

D. The equipment needed to accommodate the high temperature and pressure will be expensive to produce.​

Explanation:

Hello!

In this case, for the considered reaction, it is clear it is an exothermic reaction because it produces energy; and therefore, the higher the temperature the more reactants are yielded as the reverse reaction is favored. Moreover, since the effect of pressure is verified as favoring the side with fewer moles; in this case the products side (2 moles of ammonia).

In such a way, the high pressure favors the formation of ammonia whereas the high temperature the formation of hydrogen and nitrogen and therefore, option A is ruled out. Since the high pressure shifts the reaction rightwards and the high temperature leftwards, we would not be able to know whether the reaction has ended or not because it will be a "go and come back" process, that is why B is also discarded. Now, since hydrogen and nitrogen would be the "wastes", we discard C because they are not toxic. That is why the most accurate answer would be D. because it is actually true that such equipment is quite expensive.

Best regards!

Answer: In a chemical reaction substances elements and compounds called reactants are changed into other substances compounds and elements called products.You can't change one element into another in a chemical reaction that happens in nuclear reactions.

Explanation:

Answer:

\(\Delta _{comb}H=-2,093\frac{kJ}{mol}\)

Explanation:

Hello!

In this case, since these calorimetry problems are characterized by the fact that the calorimeter absorbs the heat released by the combustion of the substance, we can write:

\(Q_{rxn}+Q_{cal}=0\)

Thus, given the temperature change and the total heat capacity, we obtain the following total heat of reaction:

\(Q_{rxn}=-14.01kJ/K*3.69K\\\\Q_{rxn}=-51.70kJ\)

Now, by dividing by the moles in 1.04 g of cyclopropane (42.09 g/mol) we obtain the enthalpy of combustion of this fuel:

\(n=\frac{1.04g}{42.09g/mol}=0.0247mol\\\\\Delta _{comb}H=\frac{Q_{rxn}}{n}\\\\ \Delta _{comb}H=-2,093\frac{kJ}{mol}\)

Best regards!

The enthalpy of combustion of cyclopropane is \(\Delta _c_o_m_b H= - 2.093 kJ/mol\)

Enthalpy of combustion is the amount of heat produced when one mole of substance completely burns.

By the formula of calorimetry

\(Q_r_x_n + Q_c_a_l = 0\)

The temperature change and total heat capacity is

\(Q_r_x_n = -14.01 KJ/K \times 3.69 K\\\\Q_r_x_n = -51.70 KJ\)

Now, we get the enthalpy of combustion by dividing by the moles of 1.04 g of cyclopropane.

The number of moles is 42.09 g/mol.

\(n = \dfrac{1.4}{42.09} = 0.0247\\\\\Delta_c_o_m_bH =\dfrac{Q_r_x_n}{n} \\\\\Delta_c_o_m_bH = -2.093\; kJ/mol\)

Thus, the enthalpy of combustion is -2.093 kJ/mol

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Answer:

The correct option is b) SO₃(g) + NO(g) ⇌ SO₂(g) + NO₂(g)

Explanation:

The relation between Kc and Kp is given by the following equation:

\(Kp = Kc (RT)^{dn}\)

where R is the gas constant (0,082 L.atm/K.mol), T is the temperature (in K) and dn is the change in moles.

The change in moles (dn) is calculated as:

dn = moles of products - moles reactants

If dn=0, RT= 1 ⇒ Kc=Kp

We calculate dn for each reaction from the estequiometrial coefficients of products and reactants as follows:

a) 4 NH₃(g) + 3 O₂(g) ⇌ 2 N₂(g) + 6 H₂O(g)

dn= (2+6) - (4+3) = 1 ⇒ Kc ≠ Kp

b) SO₃(g) + NO(g) ⇌ SO₂(g) + NO₂(g)

dn = (1+1) - (1+1)= 0 ⇒ Kc = Kp

c) 2 N₂(g) + O₂(g) ⇌ 2 N₂O(g)

dn= 2 - (2+1) = -1 ⇒ Kc ≠ Kp

d) 2 SO₂(g) + O₂(g) ⇌ 2 SO₃(g)

dn = 2 - (2+1) = -1 ⇒ Kc ≠ Kp

The reaction in which Kc=Kp is b), because reactants and products have the same number of moles.

Answer:

0.13 M

Explanation:

The reaction equation is;

NaOH(aq) + KHC8H4O4(aq) ------> KNaC8H4O4(aq) + H2O(l)

Molar mass of KHP = 204.22 g/mol

Amount of KHP= mass/ molar mass = 0.3365 g/204.22 g/mol = 1.65 × 10^-3 moles

n= CV

Where;

C= concentration

V= volume in dm^3

n= number of moles

C= n/V = 1.65 × 10^-3 moles × 1000/250 = 6.6 × 10^-3 M

If 1 mole of KHP reacts with 1 mole of NaOH

1.65 × 10^-3 moles of KHP will react with 1.65 × 10^-3 moles of NaOH

From

n= CV

We have that only 12.44 ml of NaOH reacted

C= n/V = 1.65 × 10^-3 moles × 1000/12.44

C= 0.13 M

At the equivalence point, the KHP solution turned light pink.