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4 years ago

Calculate the given value using significant figures: 23.033 cm + 34.045 cm +55.040 mm

Chemistry

2 answers:

jeyben [28]4 years ago

8 0

Answer:

The Answer is 112.118

Explanation:

Alex787 [66]4 years ago

5 0

Answer: 62.582cm

Explanation:

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What is the molarity of 10.0 g of NaCl dissolved in water to make 100. mL?

tigry1 [53]

Answer:

= 1.7 M

Explanation:

Molecular mass of NaCl = ( 23+35.5 ) = 58.5g

58.5g of NaCl are weighed by 1 mole of NaCl

10.0g of NaCl will be weighed by ( 10÷58.5 )

 = 0.17 moles of NaCl

100mL = ( 100÷1000)L = 0.1L

0.1L of a solution is occupied by 0.17 moles of NaCl

1L of solution will be occupied by [(1÷0.1)×0.17]

=1.7 M

5 0

4 years ago

Assume that the NO, concentration in a house with a gas stove is 150 pg/m°. Calculate the equivalent concentration in ppm at STP

jok3333 [9.3K]

Explanation:

It is known that for $NO_{2}$ , ppm present in 1 $mg/m^{3}$ are as follows.

1 $\frac{mg}{m^{3}}$ = 0.494 ppm

So, 150 $pg/m^{3}$ = $\frac{150}{1000} mg/m^{3}$

= 0.15 $mg/m^{3}$

Therefore, calculate the equivalent concentration in ppm as follows.

$0.15 \times 0.494 ppm$

= 0.074 ppm

Thus, we can conclude that the equivalent concentration in ppm at STP is 0.074 ppm.

4 0

3 years ago

What type of chemical reaction occurs when more energy Is released during the chemical reaction than is needed to start the chem

Ksju [112]

Answer:

Explanation:

Exothermic Reactions

This means that the energy required to break the bonds in the reactants is less than the energy released when new bonds form in the products. Excess energy from the reaction is released as heat and light. Figure: Chemical reaction: A Hermite reaction, which produces molten iron.

3 0

3 years ago

The Law of Conservation of Energy states that Energy cannot be ____________ nor _____________ but only change from one _________

Yakvenalex [24]

3. Created, destroyed, form Is the correct answer

3 0

3 years ago

Under identical conditions, separate samples of O2 and an unknown gas were allowed to effuse through identical membranes simulta

Brut [27]

Answer:

The molar mass of unknown gas is 145.82 g/mol.

Explanation:

Volume of oxygen gas effused under time t = 8.24 mL

Effusion rate of oxygen gas = $R=\frac{8.24 mL}{t}$

Molar mass of oxygen gas = 32 g/mol

Volume of unknown gas effused under time t = 3.86 mL

Effusion rate of unknown gas = $R'=\frac{3.86 mL}{t}$

Molar mass of unknown gas = M

Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

$\text{Rate of diffusion}\propto \frac{1}{\sqrt{\text{Molar mass of the gas}}}$

$\frac{R}{R'}=\sqrt{\frac{M}{32 g/mol}}$

$\frac{\frac{8.24 mL}{t}}{\frac{3.86 mL}{t}}=\sqrt{\frac{M}{32 g/mol}}$

$M=\frac{32 g/mol\times 8.24 \times 8.24}{3.86\times 3.86}=145.82 g/mol$

4 0

3 years ago