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aleksandrvk [35]

3 years ago

11

A student decides to jump off a skateboard toward the east. Based on the action-reaction forces, which direction will the skateb

oard most likely move when she jumps off?

1 answer:

Anna11 [10]3 years ago

5 0

Answer:

l

Explanation:

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You are working in the lab, how many grams of solute you need to make 200.0 g of 3.4% of solution?

Goryan [66]

Answer:

6.8g of solute are needed

Explanation:

Percent by mass, (w/w%) is defined as the mass of solute in 100g of solution. A solution that is 3.4% contains 3.4g of solute in 100g of solution. That means to make 200g of solution are required:

200g solution * (3.4g solute / 100g solution) = 6.8g of solute are needed

6 0

3 years ago

Calculate ΔHrxnΔHrxn for the following reaction: 3C(s)+4H2(g)→C3H8(l)3C(s)+4H2(g)→C3H8(l) Use the following reactions and given

mihalych1998 [28]

<u>Answer:</u> The $\Delta H^o_{rxn}$ for the reaction is -120.9 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:

$3C(s)+4H_2(g)\rightarrow C_3H_8(l)$ $\Delta H^o_{rxn}=?$

The intermediate balanced chemical reaction are:

(1) $C_3H_8(l)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)$ $\Delta H_1=-2026.6kJ$

(2) $C(s)+O_2(g)\rightarrow CO_2(g)$ $\Delta H_2=-393.5kJ$ ( × 3)

(3) $2H_2(g)+O_2(g)\rightarrow 2H_2O(g)$ $\Delta H_2=-483.5kJ$ ( × 2)

The expression for enthalpy of the reaction follows:

$\Delta H^o_{rxn}=[1\times (-\Delta H_1)]+[3\times \Delta H_2]+[2\times \Delta H_3]$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(1\times -(-2026.6))+(3\times (-393.5))+(2\times (-483.5))]=-120.9kJ$

Hence, the $\Delta H^o_{rxn}$ for the reaction is -120.9 kJ.

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3 years ago

The chemical equation provided shows iron rusting to form iron oxide. Use the drop-down menu to choose the coefficients that wil

olchik [2.2K]

4Fe + 3O2 → 2Fe2O3 <or> The chemical formula for rust is Fe2O3. Rust is formed when iron reacts with oxygen in moist air. The following chemical equation represents the reaction: 4Fe + 3O2 → 2Fe2O3. Water is necessary for the oxidation reaction to occur and to facilitate transport of the electrons.

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3 years ago

Read 2 more answers

The first question is the one I need help with

aleksandr82 [10.1K]

I looked at the question and there isn't a lot of information. im assuming the answer is carbon dioxide. its the only substance that would make sense I hope it helps.

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3 years ago

An element is a pure substance that is defined by the number of protons in which is defined as the atomic number

Pani-rosa [81]

If this is a true or false question then the answer is true.

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3 years ago