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Olin [163]
3 years ago
6

NEED HELP! An experiment _____. must always be done in a laboratory is best done if only one variable is tested for at a time ca

n be done only by direct observation must always be done in the field
Chemistry
1 answer:
hichkok12 [17]3 years ago
6 0

Answer:

Chemically

in chemistry

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Which happens when a reversible reaction reaches a state of chemical equilibrium?
Trava [24]

Explanation:

Reversible reactions that happen in a closed system eventually reach equilibrium. At equilibrium, the concentrations of reactants and products do not change. But the forward and reverse reactions have not stopped - they are still going on, and at the same rate as each other.

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What are the two processes underlying this image that turn peat into coal
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Answer:

Peatification and coalification

Explanation:

https://energyeducation.ca/encyclopedia/Coal_formation

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Which statement best summarizes what happens during cellular respiration?
morpeh [17]

Answer:

A

Explanation:

B and D have to do with plants

and C has nothing to do with cellular resporation.

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15 grams of sodium reacts with a certain amount of chlorine to yield 37 grams of sodium chloride, as shown below.
ale4655 [162]

Answer: 22g of chlorine would be needed to carry out this synthesis reaction

Explanation:

A synthesis reaction is one in which two or more than two elements combine together to forma single product.

Na+Cl\rightarrow NaCl

The atoms present in the reactants are found on the product side. According to the law of conservation of mass, the number of atoms on both sides of the arrow must be same as the total mass must be conserved.

15 grams of sodium reacts with 22 grams of chlorine to yield 37 grams of sodium chloride. Thus 22g of chlorine would be needed to carry out this synthesis reaction.

4 0
3 years ago
Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction:P4(g) + 10 Cl2(g) → 4PCl5(s) ΔH°
miskamm [114]

<u>Answer:</u> The \Delta H^o_{rxn} for the reaction is -1835 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

P_4(g)+10Cl_2(g)\rightarrow 4PCl_5(s)      \Delta H^o_{rxn}=?

The intermediate balanced chemical reaction are:

(1) PCl_5(s)\rightarrow PCl_3(g)+Cl_2(g)    \Delta H_1=157kJ   ( × 4)

(2) P_4(g)+6Cl_2(g)\rightarrow 4PCl_3(g)     \Delta H_2=-1207kJ

The expression for enthalpy of the reaction follows:

\Delta H^o_{rxn}=[4\times (-\Delta H_1)]+[1\times \Delta H_2]

Putting values in above equation, we get:

\Delta H^o_{rxn}=[(4\times (-157))+(1\times (-1207))=-1835kJ

Hence, the \Delta H^o_{rxn} for the reaction is -1835 kJ.

6 0
3 years ago
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