All categories

3 years ago

1. If I have 45 L of He in a balloon at 25 degrees celsius and increase the temperature of the

1 answer:

7 0

Use Charles' Law: V1/T1 = V2/T2. We assume the pressure and mass of the helium is constant. The units for temperature must be in Kelvin to use this equation (x °C = x + 273.15 K).

We want to solve for the new volume after the temperature is increased from 25 °C (298.15 K) to 55 °C (328.15 K). Since the volume and temperature of a gas at a constant pressure are directly proportional to each other, we should expect the new volume of the balloon to be greater than the initial 45 L.

Rearranging Charles' Law to solve for V2, we get V2 = V1T2/T1.

(45 L)(328.15 K)/(298.15 K) = 49.5 ≈ 50 L (if we're considering sig figs).

You might be interested in

A cube has sides of 11.4 cm. What is its volume?

9966 [12]

It is A) 1,482 cm3 ..............

4 0

3 years ago

What is the molecular formula of a compound with the empirical formula

ipn [44]

Answer: $C_2H_2O_2$

Explanation:

Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.

Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.

The empirical formula is $CHO$

The empirical weight of $CHO$ = 1(12)+1(1)+1(16)= 29 g.

The molecular weight = 60 g/mole

Now we have to calculate the molecular formula:

$n=\frac{\text{Molecular weight}}{\text{Equivalent weight}}=\frac{60}{29}=2$

The molecular formula will be= $2\times CHO=C_2H_2O_2$

Thus molecular formula will be $C_2H_2O_2$

5 0

3 years ago

"How much NH4Cl, when present in 2.00 liters of 0.200 M ammonia, will give a solution with pH = 8.20? For NH3, Kb = 1.8 x 10-5"

Andru [333]

Answer:

245.66g of NH₄Cl is the mass we need to add to obtain the desire pH

Explanation:

The mixture of NH3/NH4Cl produce a buffer. We can find the pH of a buffer using H-H equation:

pH = pKa + log [A⁻] / [HA]

Where [A⁻] is the molar concentration of the base, NH₃, and [HA] molar concentration of the acid, NH₄⁺. This molar concentration can be taken as the moles of each chemical

First, we need to find pKa of NH₃ using Kb. Then, the moles of NH₃ and finally replace these values in H-H equation to solve moles of NH₄Cl we need to obtain the desire pH.

pKa NH₃/NH₄⁺

pKb = - log Kb

pKb = -log 1.8x10⁻⁵ = 4.74

pKa = 14 - pKb

pKa = 14 - 4.74

pKa = 9.26

Moles NH₃

2.00L ₓ (0.200mol NH₃ / L) = 0.400 moles NH₃

H-H equation:

pH = pKa + log [NH₃] / [NH₄Cl]

8.20 = 9.26 + log [0.400 moles] / [NH₄Cl]

-1.06 = log [0.400 moles] / [NH₄Cl]

0.0087 = [0.400 moles] / [NH₄Cl]

[NH₄Cl] = 0.400 moles / 0.0087

[NH₄Cl] = 4.59 moles of NH₄Cl we need to add to original solution to obtain a pH of 8.20. In grams (Using molar mass NH₄Cl=53.491g/mol):

4.59 moles NH₄Cl ₓ (53.491g / mol) =

<h3>245.66g of NH₄Cl is the mass we need to add to obtain the desire pH</h3>

3 0

3 years ago

__?__ is when cells divide. *

DedPeter [7]

Answer:

B.Mitosis

Explanation:

Brainliest??

7 0

3 years ago

Read 2 more answers

Sort the following chemicals for their ability to act as an oxidizer. List from strongest to weakest; 1 being strongest, 6 being

spin [16.1K]

Answer : If we list the given chemicals according to their increasing oxidising ability then the order will be like this; 1 being the strongest and 6 being the weakest
1. K > 2. Ca >3. Ni> 4. Cu> 5. Ag> 6.Au

Explanation : Considering the reduction potential of each chemical species it will be easy to identify their oxidising capacity and differentiate accordingly;

More negative the value of reduction potential more is the ability of the chemical species to get oxidised.

Chemicals with their reduction potential is given below.

K has -2.92; Ca has -2.76; Ni has -0.23; Cu has 0.52; Ag has 1.50 and Au has 1.50.

7 0

3 years ago

Read 2 more answers