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Mariana [72]
3 years ago
5

CHEMISTRY. PLEASE HELP!!

Chemistry
2 answers:
Zina [86]3 years ago
6 0

Answer:

B: It is positive when the bonds of the product store more energy than those of the reactants.

Explanation:

took the test

bixtya [17]3 years ago
3 0

Answer:

The answer is B on edge

Explanation:

Here are my notes on this section for anyone that needs them

Enthalpy and State Function

Bonds contain potential energy. Breaking and forming bonds involves energy. Reactants and products contain energy. Enthalpy (H) is a measure of heat and internal energy in a system.

A state function is a quantity whose change in magnitude during a process depends only on the beginning and end points the process, not the path taken between them. Enthalpy change during reaction depends only on the identity of reactants and products and their initial and finial condition

Enthalpy of Formation

enthalpy of formation (Hf) is the energy absorbed or released when a pure substance forms from elements in their standard states

Units: kJ/mol, kcal/mol

Standard state is the natural state of an element at 1 atm (atmosphere of pressure) and 25 degrees celsius. Hf for a pure element in its standard state is 0 kJ/mol.

H (hydrogen):    H2(g)

N (nitrogen): N2(g)

O (oxygen): O2(g)

F (fluorine): F2(g)

Cl (chlorine): Cl2(g)

Br (bromine): Br2(l)

Hg (mercury): Hg(l)

Enthalpy of Reaction

Enthalpy of reaction (Hrxn) is energy absorbed or released during a chemical reaction

Hrxn negative: exothermic reaction

Hrxn positive: endothermic reaction

Hess's Law: Hrxn =  Σ(ΔHƒ, products) − Σ(ΔHƒ, reactants)

thermochemical equation: the chemical equation that shows the state of each substance involved and the energy change involved in a reaction

Find the kJ/mol of the product and then subtract the kJ/mol of the reactants.

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Individual measurements introduce errors that may be large or small depending on the quality of the tools and processes used. Sc
kirill [66]

Answer:

B. accepted value x 0.1

Explanation:

in the equation provided

Percentage Error=\frac{Error}{AcceptedValue} X100

Maximum allowed value of percentage error = 10%

put this value in the equation in stead of percentage error we get,

10 = \frac{error}{AcceptedValue} X100\\ \frac{10}{100} =\frac{error}{AcceptedValue}\\.1=\frac{error}{AcceptedValue}\\error = .1 X Accepted Value

so maximum error = .1 x accepted value

10 % percentage error means the experimental value has 10 % error compared to accepted value.so error will be 10 % of the accepted value

or .1 times of accepted value

8 0
3 years ago
Would the solubility for a substance increase by dissolving the solute with more water?
garik1379 [7]

Answer: Yes

Explanation:

With more water, the molecules of the substance have more water molecules to form bonds with, thus they are dissolved even faster at that same particular temperature.

For example: a mildly soluble substance like powdered milk get more dissolved in your teacup as water, the solvent is increased

8 0
3 years ago
Methane gas and chlorine gas react to form hydrogen chloride gas and carbon tetrachloride gas. what volume of hydrogen chloride
Anna71 [15]
The reaction between methane gas and chlorine gas to form hydrogen chloride and carbon tetrachloride, all in their gaseous form can be expressed through the chemical reaction below.

        CH₄ + 4Cl₂ --> 4HCl + CCl₄

Let us assume that all the involved gases behaves ideally such that each mole of the gas is equal to 22.4 L. 

Through proper dimensional analysis, the volume of the produced hydrogen chloride is calculated,
    V(HCl) = (1.69 mL CH₄)(1 L CH₄/ 1000 mL CH₄)(1 mol CH₄/22.4 L CH₄)(4 mols HCl/1 mol CH₄)(22.4 L HCl/1 mol HCl)(1000 mL/1 L)
    

    V(HCl) = 6.76 mL

<em>ANSWER: 6.76 mL</em>


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