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3 years ago

There is enough energy in air at room temperature to change some

Chemistry

1 answer:

Pavel [41]3 years ago

8 0

Answer:

Explanation:

There is enough energy in air at room temperature to change some liquids to gases. The temperature of ice water is lower than the temperature of dry ice in alcohol. Carbon dioxide can change directly from the solid phase to the gaseous phase. ... Absolute zero is the temperature at which there is no molecular motion.

Answer: True

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A runner covers the last straight stretch of a race in 4 s. During that time, he speeds up from 5 m/s to 9 m/s. What is the runn

sattari [20]

Answer:

1m/s^2

Explanation:

u= 5 m/s

v= 9 m/s

t= 4s

But

a= v-u/t

a= 9-5/4

a= 4/4

a= 1m/s^2

8 0

4 years ago

Read 2 more answers

If 20 grams of sulfur reacts with 30 grams of oxygen, predict the mass of sulfur trioxide produced. Why would you expect this

Scilla [17]

20/32=0.625 moles of sulfur
30/16 = 1.875 moles of oxygen
The formula requires 1 mole of sulfur for 3 moles of oxygen which means that their is no limiting reactant as that is the ratio found thus it will react to completion forming 50 grams of product or sulfur trioxide

4 0

3 years ago

Dissolve 7, 8 grams of Mg and Al mixture with excess HCl solution. After the reaction, the mass of acid solution increased by 7,

fgiga [73]

Answer:

Mg = 2,5 g; Al = 5,3 g

Explanation:

1) Reactions

Mg + 2HCl ⟶ MgCl₂ + H₂

2Al + 6HCl ⟶ 2AlCl₃ + 3H₂

2) Mass of each metal

If there had been no reaction, the mass of the solution would have increased by 7,8 g.

The mass increased by only 7,0 g.

The missing 0,8 g must represent the mass of the hydrogen generated by the reaction.

We have two relations:

Mass of Mg + mass of Al = 7,8 g

H₂ from Mg + H₂ from Al = 0,8 g

i) Calculate the moles of H₂

$n = \text{0,8 g H}_{2} \times \dfrac{\text{1 mol H}_{2}}{\text{2,016 g H}_{2}} = \text{0.40 mol H}_{2}$

(ii) Solve the relationship

Let x = mass of Mg. Then

7,8 - x = mass of Al

Moles of Mg = x/24.30

Moles of Al = (7,8 - x)/26.98

Moles of H₂ from Mg = (1/1) × moles of Mg = 1 × (x/24,30) = 0,0412x

Moles of H₂ from Al = (3/2) × Moles of Al = 1.5(7,8 - x)/26,98 = (11,7 -1,5x)/26,98

$\begin{array}{rcl}0,0412x + \dfrac{ 11,7 - 1,5x }{26,98} &= &0,40\\\\ 1,11x + 11.7 - 1,5x &=& 10.7\\-0.39x& = &-1.0\\x &=& \text{2.5 g}\\\end{array}$

Mass of Mg = 2,5 g

Mass of Al = 7,8 g - 2,5 g = 5,3 g

The masses of the metals are Mg = 2,5 g; Al = 5,3 g

6 0

3 years ago

What happens to air pressure as altitude increases

Anastaziya [24]

Pressure with Height: pressure decreases withincreasing altitude. The pressure at any level in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels.....

5 0

4 years ago

Read 2 more answers

CaC2 + 2H2O(I) = C2H2(g) + Ca(OH)2(aq) how many grams of Ca(OH)2 would be formed with 3.20 moles of CaC2?

Jobisdone [24]

Answer:

236.8 g

Explanation:

From the reaction equation;

CaC2 + 2H2O(I) --------> C2H2(g) + Ca(OH)2(aq)

Since;

1 mole of CaC2 yields 1 mole of Ca(OH)2

It follows that 3.20 moles of CaC2 also yields 3.2 moles of Ca(OH)2

Mass of Ca(OH)2 = number of moles * molar mass

molar mass of Ca(OH)2 = 74 g/mol

Mass of Ca(OH)2 = 3.20 moles * 74 g/mol =

Mass of Ca(OH)2 = 236.8 g

3 0

3 years ago