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scoundrel [369]
3 years ago
9

How many times should you rinse a pipet before transferring liquid? 2- once with tap water and once with deionized water?

Chemistry
1 answer:
tia_tia [17]3 years ago
8 0
You need to rinse a few times with clean water to dilute and rinse out whatever was in there previously. Then rinse with the solution to be pipetted to rinse out the water and to ensure the solution sits level in the pipette.

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If 2.00 g of Zn is allowed to react with 2.00 g of CuSO4, how many grams of
otez555 [7]

Answer:

dk

Explanation:

8 0
3 years ago
Read 2 more answers
Explain how changing the concentration The enthalpy change for the reaction, 3CO (g) 2Fe2O3 (s) Imported Asset Fe(s) 3CO2 (g), c
ycow [4]

<u>Answer:</u> For the given equation, only iron has the value of \Delta H_f equal to 0 kJ.

<u>Explanation:</u>

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as \Delta H^o

The equation used to calculate enthalpy change is of a reaction is:

\Delta H^o_{rxn}=\sum [n\times \Delta H^o_f(product)]-\sum [n\times \Delta H^o_f(reactant)]

For the given chemical reaction:

3CO(g)+2Fe_2O_3(s)\rightarrow Fe(s)+3CO_2(g)

The equation for the enthalpy change of the above reaction is:

\Delta H^o_{rxn}=[(1\times \Delta H^o_f_{(Fe(s))})+(3\times \Delta H^o_f_{(CO_2(g))})]-[(3\times \Delta H^o_f_{(CO(g))})+(2\times \Delta H^o_f_{(Fe_2O_3(s))})]

The enthalpy of formation for the substances present in their elemental state is taken as 0.

Here, iron is present in its elemental state which is solid.

Hence, for the given equation, only iron has the value of \Delta H_f equal to 0 kJ.

7 0
3 years ago
What part of the atom determines if it will combine or break apart from other substances
enyata [817]

The combination of an atom with other atom is bonding. Or break apart from other substance is breaking of interaction.

The bonding or interaction (inter-atomic) are due orbitals and electrons present in these orbitals

The atom consists of

a) a central nucleus which has proton and neutrons: they do not take part in chemical reactions

b) the part other than nucleus which has shells, sub shells and orbitals

These orbitals have electrons.

So the outer part of nucleus takes part in any combination with other substance

7 0
4 years ago
What is the electronegativity in the determination of the ionic or covalent character of a bond
Paladinen [302]

Polar Covalent is the name used to describe bonds that have both ionic and covalent character because the electrons are shared unequally. The Pauling Scale is used to assign electronegativity to atoms. It ranges from to 4.00 (fluorine).

8 0
4 years ago
Según la Organización Mundial de la Salud, el nitrato de plata ( densidad = 4.35 g/cc ) es una sustancia con propiedades cáustic
OlgaM077 [116]

Answer:

737.52 mL de agua

Explanation:

En este caso solo debes usar la expresión de molaridad de una solución la cual es:

M = moles / V

Donde:

V: Volumen de solución.

Como queremos saber la cantidad de agua, queremos saber en otras palabras cual es la cantidad de solvente que se utilizó para preparar los 800 mL de disolución.

Una disolución se prepara con un soluto y solvente. El soluto lo tenemos, que es el nitrato de plata. Con la expresión de arriba, calculamos los moles de soluto, y luego su masa. Posteriormente, calculamos el volumen con la densidad, y finalmente podremos calcular el solvente de esta forma:

V ste = Vsol - Vsto

Primero calcularemos los moles de soluto:

moles = M * V

moles = 2 * 0.800 = 1.6 moles

Con estos moles, se calcula la masa usando el peso molecular reportado que es 169.87 g/mol:

m = moles * PM

m = 1.6 * 169.87 = 271.792 g

Ahora usando el valor de la densidad, calcularemos el volumen de soluto empleado:

d = m/V

V = m/d

V = 271.792 / 4.35

V = 62.48 mL

Finalmente, la cantidad de agua necesaria es:

V agua = 800 - 62.48

V agua = 737.52 mL

8 0
3 years ago
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