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LenKa [72]
3 years ago
10

SHOW WORK AND INCLUDE UNITS

Chemistry
1 answer:
Ber [7]3 years ago
6 0

Answer:

36365.4 Joules

Explanation:

The quantity of Heat Energy (Q) released on cooling a heated substance depends on its Mass (M), specific heat capacity (C), and change in temperature (Φ)

Thus, Q = MCΦ

Since, M = 45.4 g

C = 3.56 J/g°C,

Φ = 250°C - 25°C = 225°C

Q = 45.4g x 3.56J/g°C x 225°C

Q= 36365.4 Joules

Thus, 36365.4 Joules of heat energy is released when the lithium is cooled.

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lina2011 [118]
Hello!
I saw this question and instantly knew I could help. I recently took a course on toxic gasses and poisons. Here's what I know.

It can be swallowed, inhaled, or absorbed through skin. It is generally released from its host compound by acids, such as the hydrochloric acid found in the stomach. The poison in the seeds is released only if the seeds are chewed.

Effects and symptoms:
Cyanide prevents the red blood cells from absorbing oxygen. It's called chemical asphyxia.
Smelling of a toxic dose of the gas can cause immediate unconsciousness, convulsions and death within one to fifteen minutes.
If swallowed a fatal dose can take up to twenty minutes or longer, esp. if swallowed on a full stomach.
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5 0
3 years ago
2.50 liter of a gas has a pressure of 165. kPa at 25.0°C. If the pressure increases to 600. kPa and the temperature to 100.0°C,
tiny-mole [99]

Answer:

0.861 L

Explanation:

We are given pressure, volume, and temperature, so let's apply the Combined Gas Law:

(P₁V₁)/T₁ = (P₂V₂)/T₂

Convert the temperatures to degrees Kelvin.

25.0°C -> 298 K, 100.0°C -> 373 K

Plug in the initial conditions on the left, then the final/new on the right, and solve for the unknown:

(165(2.5))/298 = (600(V₂))/373

V₂ = (165(2.5)(373))/(298(600))

V₂ = 0.861 L

7 0
3 years ago
Determine the pHpH of an HFHF solution of each of the following concentrations. In which cases can you not make the simplifying
PIT_PIT [208]

The question is incomplete, complete question is :

Determine the pH of an HF solution of each of the following concentrations. In which cases can you not make the simplifying assumption that x is small? (K_a for HF is 6.8\times 10^{-4}.)

[HF] = 0.280 M

Express your answer to two decimal places.

Answer:

The pH of an 0.280 M HF solution is 1.87.

Explanation:3

Initial concentration if HF = c = 0.280 M

Dissociation constant of the HF = K_a=6.8\times 10^{-4}

HF\rightleftharpoons H^++F^-

Initially

c          0            0

At equilibrium :

(c-x)      x             x

The expression of disassociation constant is given as:

K_a=\frac{[H^+][F^-]}{[HF]}

K_a=\frac{x\times x}{(c-x)}

6.8\times 10^{-4}=\frac{x^2}{(0.280 M-x)}

Solving for x, we get:

x = 0.01346 M

So, the concentration of hydrogen ion at equilibrium is :

[H^+]=x=0.01346 M

The pH of the solution is ;

pH=-\log[H^+]=-\log[0.01346 M]=1.87

The pH of an 0.280 M HF solution is 1.87.

6 0
3 years ago
what is magnesium? why does your body need it? how much do you need (per day)? What happens if you have too much or too little o
Sav [38]

Magnesium is a nutrient that the body needs to stay healthy. if you dont get enough magnesium in your body then you could get magnesium deficiency. Symptoms of magnesium deficiency include loss of appetite, nausea, vomiting, fatigue, and weakness. Extreme magnesium deficiency can cause numbness, tingling, muscle cramps, seizures, personality changes, and an abnormal heart rhythm. The RDA for magnesium is 310–420 mg for adults depending on age and gender. Sources of magnesium are greens, nuts, seeds, dry beans, whole grains and low-fat dairy products.

random facts:

A magnesium ion is present in the chlorophyll molecule of every living green plant.

Magnesium is critically important for the human metabolic system's functioning.

8 0
3 years ago
30 pts! Sodium and water react according to the following equation. If 31.5g of sodium are added to excess water, how many liter
mihalych1998 [28]
First, calculate the number of moles of sodium present with the given mass,

              31.5 g of sodium x (1 mol sodium/ 23 g sodium) = 1.37 mol sodium

It is given in the equation that for every 2mols of sodium, one mol of H2 is produced.

           mols of H2 = (1.37 mols sodium)(1 mol H2/ 2 mols sodium)
                  mols of H2 = 0.685 mols H2

Then, at STP, 1 mol of gas = 22.4 L.
                
                 volume of H2 = (0.685 mols H2)(22.4 L / 1 mol)
                     volume of H2 = 15.34 L

Answer: 15.34 L
3 0
4 years ago
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