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3 years ago

A) Which of the following equations model the law of conservations of mass? Ca + 2HCI - H2 + CaCl2 or

Chemistry

1 answer:

nydimaria [60]3 years ago

4 0

Answer:

The first equation

Explanation:

For these problems, it is best to label and record how many of each element are on each side of the equation. The first equation has 1 Ca, 2H, and 2Cl on both sides while the second equation has 3H on the left and 2H on the right making the second equation incorrect.

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Calculate the average atomic mass of element X using the table below. Then use the periodic table to identify the element. Separ

Ksenya-84 [330]

Answer:

126.8, Iodine

Explanation:

mass ×abundance/100
(126.9045×80.45/100)+(126.0015×17.23/100)+(128.2230×2.23/100)
102.1+21.7+3=126.8

IODINE has an atomic mass of 126.8 or 126.9

4 0

3 years ago

How many moles are in 8.35 g of H2O?

AlexFokin [52]

It’s is 130 that is the answer!!!!

8 0

2 years ago

Explain how dalton's theory of the atom and the conservation of mass are related

Scorpion4ik [409]

Answer:

Dalton's atomic theory states that atoms may be mixed in certain rations to produce compounds, while the law of conservation of mass states that the mass of reactants equals the mass of products. They are related because in the production of compounds, Dalton made it clear that mass can neither be destroyed or created, which supports the conservation of mass law.

Explanation:^^^

Hoped it helped...

8 0

3 years ago

Biacetyl, the flavoring that makes margarine taste "just like butter," is extremely stable at room temperature, but at 200°C it

Sholpan [36]

Answer:

3.91 minutes

Explanation:

Given that:

Biacetyl breakdown with a half life of 9.0 min after undergoing first-order reaction;

As we known that the half-life for first order is:

$t__{1/2}}= \frac{0.693}{k}$

where;

k = constant

The formula can be re-written as:

$k = \frac{0.693}{t__{1/2}}$

$k = \frac{0.693}{9.0 min}$

$k = 0.077 min^{-1}$

Let the initial amount of butter flavor in the food be $(N_0)$ = 100%

Also, the amount of butter flavor retained at 200°C $(N_t)$ = 74%

The rate constant $k = 0.077 min^{-1}$

To determine how long can the food be heated at this temperature and retain 74% of its buttery flavor; we use the formula:

$\frac{N_t}{N_0}= -kt$

$t = - (\frac{1}{k}*In\frac{N_t}{N_0} )$

Substituting our values; we have:

$t = - (\frac{1}{0.077}*In\frac{74}{100} )$

t = 3.91 minutes

∵ The time needed for the food to be heated at this temperature and retain 74% of its buttery flavor is 3.91 minutes

4 0

3 years ago

The following mechanism has been suggested for the reaction between nitrogen monoxide and oxygen: NO(g) + NO(g) → N2O2(g) (fast)

Karo-lina-s [1.5K]

Answer:

b. Second order in NO and first order in O₂.

Explanation:

A. The mechanism

$\rm 2NO\xrightarrow[k_{-1}]{k_{1}}N_{2}O_{2} \, (fast)\\\rm N_{2}O_{2} + O_{2}\xrightarrow{k_{2}} 2NO_{2} \, (slow)$

B. The rate expressions

$-\dfrac{\text{d[NO]} }{\text{d}t} = k_{1}[\text{NO]}^{2} - k_{-1} [\text{N}_{2}\text{O}_{2}]^{2}\\\\\rm -\dfrac{\text{d[N$_{2}$O$_{2}$]}}{\text{d}t} = -\dfrac{\text{d[O$_{2}$]}}{\text{d}t} = k_{2}[ N_{2}O_{2}][O_{2}] - k_{1} [NO]^{2}\\\\\dfrac{\text{d[NO$_{2}$]}}{\text{d}t}= k_{2}[ N_{2}O_{2}][O_{2}]$

The last expression is the rate law for the slow step. However, it contains the intermediate N₂O₂, so it can't be the final answer.

C. Assume the first step is an equilibrium

If the first step is an equilibrium, the rates of the forward and reverse reactions are equal. The equilibrium is only slightly perturbed by the slow leaking away of N₂O₂ to form product.

$\rm k_{1}[NO]^{2} = k_{-1} [N_{2}O_{2}]\\\\\rm [N_{2}O_{2}] = \dfrac{k_{1}}{k_{-1}}[NO]^{2}$

D. Substitute this concentration into the rate law

$\rm \dfrac{\text{d[NO$_{2}$]}}{\text{d}t}= \dfrac{k_{2}k_{1}}{k_{-1}}[NO]^{2} [O_{2}] = k[NO]^{2} [O_{2}]$

The reaction is second order in NO and first order in O₂.

8 0

3 years ago