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3 years ago

astronauts brought back 500 lb rock samples from the moon. how many kilograms did they bring back (1 kg = 2.20 lbs)

Chemistry

2 answers:

Mariana [72]3 years ago

6 0

500÷2.20=227.2727273kg

tigry1 [53]3 years ago

4 0

Astronauts brought back 500 lb of rock samples from the moon. How many kilograms did they bring back? (1 kg = 2.20 lb)

A. 500 kg

B. 1,100 kg

C. 498 kg

D. 227 kg

I believe it is D.

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3 years ago

What is the texture and appearance of oil

alexgriva [62]

Explanation:

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4 years ago

You make 1 Liter of an aqueous solution containing 9.20 ml of 57.8 mM acetic acid and 56.2 mg of sodium acetate (MW = 82.0 g/mol

Whitepunk [10]

Answer:

a) 5,3176x10⁻⁴ moles

b) 6,85x10⁻⁴ moles

c) The appropriate formula to calculate is Henderson-Hasselbalch.

d) pH = 4,86. Acidic solution but slighty

Explanation:

a) moles of acetic acid:

9,20x10⁻³L × 57,8x10⁻³M = 5,3176x10⁻⁴ moles

b) moles of sodium acetate:

56,2x10⁻³g ÷ 82,0 g/mole = 6,85x10⁻⁴ moles

c) The appropriate formula to calculate is Henderson-Hasselbalch:

pH= pka + log₁₀ $\frac{[A^-]}{[HA]}$

d) pH= 4,75 + log₁₀ $\frac{[6,85x10_{-4}]}{[5,3176x10_{-4}]}$

pH = 4,86

3 < pH < 7→ Acidic solution but slighty

I hope it helps!

3 0

4 years ago

Write a balanced half-reaction for the reduction of gaseous oxygen to aqueous hydrogen peroxide in basic aqueous solution. Be su

Vesna [10]

Answer:

Balanced half-reaction: $O_{2}(g)+2H_{2}O(l)+2e^{-}\rightarrow H_{2}O_{2}(aq.)+2OH^{-}(aq.)$

Explanation:

Balanced half-reaction for the reduction of gaseous oxygen to aqueous hydrogen peroxide in basic solution should be written in the following step-by-step manner:

Half-reaction: $O_{2}(g)\rightarrow H_{2}O_{2}(aq.)$

Balance H and O in basic medium: $O_{2}(g)+2H_{2}O(l)\rightarrow H_{2}O_{2}(aq.)+2OH^{-}(aq.)$

Balance charge: $O_{2}(g)+2H_{2}O(l)+2e^{-}\rightarrow H_{2}O_{2}(aq.)+2OH^{-}(aq.)$

Balanced half-reaction: $O_{2}(g)+2H_{2}O(l)+2e^{-}\rightarrow H_{2}O_{2}(aq.)+2OH^{-}(aq.)$

7 0

4 years ago

Calcium oxide or quicklime (CaO) is used in steelmaking, cement manufacture, and pollution control. It is prepared by the therma

Elena-2011 [213]

Answer:

The yearly release of $CO_2$ into the atmosphere is $6.73\times 10^{10} kg$ .

Explanation:

$CaCO_3(s)\rightarrow CaO(s) + CO_2(g)$

Annual production of CaO = $8.6\times 10^{10} kg=8.6\times 10^{13} g$

Moles of CaO :

$\frac{8.6\times 10^{13} g}{56 g/mol}=1.53\times 10^{12} moles$

According to reaction, 1 mole of CaO is produced along with 1 mole of carbon-dioxide.

Then along with $1.53\times 10^{12} moles$ of CaO moles of carbon-dioxide moles produced will be:

$\frac{1}{1}\times 1.53\times 10^{12} moles=1.53\times 10^{12} moles$ of carbon-dioxide

Mass of $1.53\times 10^{12}$ moles of carbon-dioxide:

$1.53\times 10^{12}mol\times 44 g/mol=6.73\times 10^{13} g =6.73\times 10^{10} kg$

The yearly release of $CO_2$ into the atmosphere is $6.73\times 10^{10} kg$ .

6 0

3 years ago