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3 years ago

If a climate scientist says, "The CO2 concentration in 2018 was 407.4 ppm." What do they mean? *

Chemistry

1 answer:

Alinara [238K]3 years ago

6 0

Answer:

Ppm <u>means the concentration of vapors or gases</u> expressed in parts per million of polluted air.

Explanation:

In Chemistry and Physics, part per million or PPM is a measure that expresses the number of units of a certain existing substance for every million units of the mixture. (Concentration)

In climate the equation is used so:

ppm = parts of polluted air / million parts of air .

ppm = Liters of polluted air / 10∧6 Liters of air.

This is used to find the concentration of gases expressed as parts of gas per million parts of the

polluted air.

In this case, it would be<u> 407.4L of CO2 per 10∧6L of air.</u>

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Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 15.4 u.

mixas84 [53]

Answer:

N, B, Be, C

Explanation:

N (Nitrogen) has 14.0067 B (Boron) has 10.81 Be (Beryllium) has 9 and C (Carbon) has 12

8 0

2 years ago

slader An experiment is carried out where 13.9 g of solid NaOH is dissolved in 250.0 g of water in a coffee-cup calorimeter. Dis

kvv77 [185]

Answer:

The mass of the surrounding is $M_t = 263.9 \ g$

Explanation:

From the question we are told that

The mass of $NaOH$ is $m = 13.9 \ g$

The mass of water is $m_w = 250.0g$

The chemical equation for the dissociation process is

$NaOH _{(s) } ---> Na^{+}_{(aq)} + OH^{-} _{(aq)}$

The specific heat capacity of the mixture is $c_p = 4.18 J g^{-1} C^{-1}$

The combined mass of the solution is

$M_t = 13 + 250$

$M_t = 263.9 \ g$

The mass of the surround here is the mass of the coffee-cup calorimeter and this contain the mixture ( water and the NaOH ) so the mass of the surrounding is

$M_t = 263.9 \ g$

3 0

3 years ago

What volume of CH4(g), measured at 25oC and 745 Torr, must be burned in excess oxygen to release 1.00 x 106 kJ of heat to the su

anastassius [24]

Answer:

$V=27992L=28.00m^3$

Explanation:

Hello,

In this case, the combustion of methane is shown below:

$CH_4+2O_2\rightarrow CO_2+2H_2O$

And has a heat of combustion of −890.8 kJ/mol, for which the burnt moles are:

$n_{CH_4}=\frac{-1.00x10^6kJ}{-890.8kJ/mol}= 1122.6molCH_4$

Whereas is consider the total released heat to the surroundings (negative as it is exiting heat) and the aforementioned heat of combustion. Then, by using the ideal gas equation, we are able to compute the volume at 25 °C (298K) and 745 torr (0.98 atm) that must be measured:

$PV=nRT\\\\V=\frac{nRT}{P}=\frac{1122.6mol*0.082\frac{atm*L}{mol*K}*298K}{0.98atm}\\\\V=27992L=28.00m^3$