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3 years ago

8

Margret claimed that she needed 5.45 moles of Potassium Chloride, KCl to complete her experiment. How many grams of KCl does she

need?

1 answer:

zubka84 [21]3 years ago

3 0

Answer:

loiuygfcx

Explanation:

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Which type of system must exist for chemical equilibrium

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Answer: closed system.

Explanation:

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3 years ago

What is the frequency of a photon with an energy of 3.26 x 10-19 J?

Kobotan [32]

Answer:

B.

$from \: eisteins \: energy \: relation : \\ E = hf \\ h \: is \: plancks \: constant\\ 3.26 \times {10}^{ - 19} = 6.63 \times {10}^{ - 34 } \times f \\ f = \frac{3.26 \times {10}^{ - 19} }{6.63 \times {10}^{ - 34} } \\ f = 4.92 \times {10}^{14} \: Hz$

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3 years ago

The equation shown represents cellular respiration. Glucose + X → Y + Water + Energy What do X and Y most likely represent? X re

777dan777 [17]

Answer:

X represents oxygen and Y represents carbon dioxide.

Explanation:

Because in respiration, you consume oxygen and make carbon dioxide whereas, in photosynthesis, the equation is reversed and you use carbon dioxide and make oxygen and glucose.

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3 years ago

One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titrating a sample of silv

Flauer [41]

Answer:

1.1 × 10⁻⁴ M

Explanation:

Let's consider the following double displacement reaction.

CuCl₂(aq) + 2 AgNO₃(aq) → 2 AgCl(s)+ Cu(NO₃)₂(aq)

We can establish the following relations:

The molar mass of AgCl is 143.32 g/mol.
The molar ratio of AgCl to CuCl₂ is 2:1

The moles of CuCl₂ that reacted to produce 7.7 mg of AgCl are:

$7.7 \times 10^{-3} gAgCl.\frac{1molAgCl}{143.32gAgCl} .\frac{1molCuCl_{2}}{2molAgCl} =2.7 \times 10^{-5}molCuCl_{2}$

The molarity of CuCl₂ is:

$M=\frac{2.7 \times 10^{-5}molCuCl_{2}}{0.250L} =1.1\times 10^{-4} M$

7 0

3 years ago

Approximately how many ice cubes must melt to cool 650 milliliters of water from 29°C to 0°C? Assume that each ice cube contains

qwelly [4]

Answer : The number of ice cubes melt must be, 13

Explanation :

First we have to calculate the mass of water.

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}$

Density of water = 1.00 g/mL

Volume of water = 650 mL

$\text{Mass of water}=1.00g/mL\times 650mL=650g$

Now we have to calculate the heat released on cooling.

Heat released on cooling = $m\times c\times (T_2-T_1)$

where,

m = mass of water = 650 g

c = specific heat capacity of water = $4.18J/g^oC$

$T_2$ = final temperature = $29^oC$

$T_2$ = initial temperature = $0^oC$

Now put all the given values in the above expression, we get:

Heat released on cooling = $650g\times 4.18J/g^oC\times (29-0)^oC$

Heat released on cooling = 78793 J = 78.793 kJ (1 J = 0.001 kJ)

As, 1 ice cube contains 1 mole of water.

The heat required for 1 ice cube to melt = 6.02 kJ

Now we have to calculate the number of ice cubes melted.

Number of ice cubes melted = $\frac{\text{Total heat}}{\text{Heat for 1 ice cube}}$

Number of ice cubes melted = $\frac{78.793kJ}{6.02kJ}$

Number of ice cubes melted = 13.1 ≈ 13

Therefore, the number of ice cubes melt must be, 13

3 0

3 years ago