All categories

2 years ago

The population of the world is: increasing decreasing no longer changing

1 answer:

3 0

Increasing every day. in 2013, we had about 7.125 Billion. in 9160, we had closer to 3 billion. It is still on a pretty steady clime today.

You might be interested in

Free 100 for the boys

Drupady [299]

Ok thanks wkwksnmenenenenenenwnwnnwnwnwnw

6 0

2 years ago

Read 2 more answers

Two solutions, initially at 24.60 °C, are mixed in a coffee cup calorimeter (Ccal = 15.5 J/°C). When a 100.0 mL volume of 0.100

yulyashka [42]

Answer:

ΔH = -59.6kJ/mol

Explanation:

The reaction that occurs between Ag⁺ and Cl⁻ ions is:

Ag⁺ + Cl⁻ → AgCl(s) + ΔH

To find ΔH we need to obtain moles of reaction and heat released in the reaction because ΔH is defined as heat released per mole of reaction.

<em>Moles of reaction:</em>

Moles of Ag⁺ and Cl⁻ added are:

Ag⁺: 0.100L * (0.100mol / L) = 0.01moles

Cl⁻: 0.100L * (0.200mol / L) 0 0.02 moles

That means limiting reactant is Ag⁺ and moles of reaction are 0.01 moles

<em>Heat released:</em>

To find heat released we must use coffe cup calorimeter equation:

Q = C*m*ΔT

<em>Where C is specific heat of solution (4.18J/g°C), m is the mass of solution (200g because there are 100 + 100mL = 200mL and density of solution is 1g/mL) and ΔT is change in temperature (25.30°C - 24.60°C = 0.70°C).</em>

Replacing:

Q = C*m*ΔT

Q = 4.18J/g°C * 200g * 0.70°C

Q = 585,2J

Is total heat released.

The calorimeter absorbs:

15.5J / °C * 0.7°C = 10.85

Thus, when 0.01 moles reacts, 585.2J + 10.85 = 596.05J are released (Heat released is heat abosrbed by calorimeter + Heat absorbed by water) and ΔH is:

ΔH = 596.05J / 0.01 moles =

ΔH = 59605J / mol =

<em>As heat is released, ΔH < 0.</em>

6 0

3 years ago

A gas that effuses through a porous cylinder 1.87 times faster than chlorine gas. what is the molar mass and identity.

Rufina [12.5K]

From the Graham's law of effusion;
R1/R2 = √MM2/√MM1
Molar mass of chlorine gas is 71
Therefore;
1.87= √ 71 /√mm1
= 1.87² = 71/mm1
mm1 = 71/1.87²
= 71/3.4969
= 20.3
Thus, the molar mass of the other gas is 20.3 , and i think the gas is neon

6 0

3 years ago

What would the volume of gas be at 150 c if it had a volume of 693 ml at 45 c

marissa [1.9K]

Answer:

$\boxed{\text{922 mL}}$

Explanation:

The pressure is constant, so we can use Charles' Law to calculate the volume.

$\dfrac{V_{1}}{T_{1}} = \dfrac{V_{2}}{T_{2}}$

Data:

V₁ = 693 mL; T₁ = 45 °C

V₂ = ?; T₂ = 150 °C

Calculations:

(a) Convert temperature to kelvins

T₁ = ( 45 + 273.15) = 318.15 K

T₂ = (150 + 273.15) = 423.15 K

(b) Calculate the volume

$\dfrac{ 693}{318.15} = \dfrac{ V_{2}}{423.15}\\\\2.178 = \dfrac{ V_{2}}{423.15}\\\\V_{2} = 2.178 \times 423.15 = \boxed{\textbf{922 mL}}$

5 0

3 years ago

How many Br atoms are in 1.98 g of Br?

Mkey [24]

Answer:

1.5 x 10²²atoms

Explanation:

Given parameters:

Mass of Br = 1.98g

Unknown:

Number of atoms

Solution:

A mole of a substance is the amount of substance contained in the avogadro's number of particles.

To solve this problem, we must first find the number of moles present in the given mass of the Br atom:

Number of moles = $\frac{mass}{molar mass}$ = $\frac{1.98}{80}$ = 0.025mole.

Now we know that:

1 mole = 6.02 x 10²³

0.025 mole = 0.025 x 6.02 x 10²³ = 1.5 x 10²²atoms

7 0

3 years ago