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3 years ago

What is the oxidation number of chromium in dichromate ion, cr2o72-?

1 answer:

8 0

Oxidation number is charge of element in compound. Can be neutral, positive or negative.
Oxygen in dichromate has oxidation number -2, becauce there are seven oxygens, net oxidation number of oxygen is -14.
2·x(oxidation number of Cr) + 7· (-2) = -2 2x= +12
x= +6, oxidation number of one chromium is +6.

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SOMEONE PLEASE HELP

Zinaida [17]

Answer:

6. 7870 kg/m³ (3 s.f.)

7. 33.4 g (3 s.f.)

8. 12600 kg/m³ (3 s.f.)

Explanation:

6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.

1 kg= 1000g

1m³= 1 ×10⁶ cm³

Mass of iron bar

= 64.2g

= 64.2 ÷1000 kg

= 0.0642 kg

Volume of iron bar

= 8.16 cm³

= 8.16 ÷ 10⁶

$= 8.16 \times 10^{ - 6} \: kg$

$\boxed{density = \frac{mass}{volume} }$

Density of iron bar

$= \frac{0.0642}{8.16 \times 10^{ - 6} }$

= 7870 kg/m³ (3 s.f.)

$\boxed{mass = density \: \times volume}$

Mass

= 1.16 ×28.8

= 33.408 g

= 33.4 g (3 s.f.)

8. Volume of brick

= 12 cm³

$= 12 \times 10^{ - 6} \: m^{3} \\ = 1.2 \times 10^{ - 5} \: m ^{3}$

Mass of brick

= 151 g

= 151 ÷ 1000 kg

= 0.151 kg

Density of brick

= mass ÷ volume

$= \frac{0.151} {1.25 \times 10^{ - 5} } \\ = 12600 \: kg/ {m}^{3}$

(3 s.f.)

6 0

3 years ago

The total number of oxygen atoms indicated by formula Cu3(PO4)2?

ASHA 777 [7]

Answer:

There's a total of 8 oxygen atoms in the formula Cu3(PO4)2

6 0

3 years ago

What are the differences between HDL and LDL?

il63 [147K]

Answer:

LDL is

low density lipid

HDL is

high density lipid

Explanation:

HDL helps rid your body is excess cholesterol so so it won't end up in your arteries

LDL is also called "bad cholesterol" because it takes cholesterol to your arteries

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3 years ago

If 5 moles of P4 reacted with 22 moles Cl2 according to the above reaction, determine:

GaryK [48]

Solution:

$P_4+6Cl_2\rightarrow 4PCl_3$

a) By stoichoimetry If 6 moles of $Cl_2$ gives 4 mole of $PCl_3$ , then 22 moles of $Cl_2$ will give: $\frac{4}{6}\times 22=\frac{44}{3}=14.66$ moles of $PCl_3$

b) If 6 moles of $Cl_2$ reacts with one mole of $P_4$ , then 22 moles of $Cl_2$ will react : $\frac{1}{6}\times 22=\frac{11}{3}=3.66$ moles of $P_4$

Moles of $P_4$ left after the reaction = $5-3.66=\frac{4}{3}=1.34$ moles.

c) 0 Moles of $Cl_2$ , since it is present in less amount it will get completely consumed in the reaction. Hence, it is limiting reagent.

7 0

3 years ago

What would happen if the aspects that allow to maintain the characteristics of the states were altered?

irinina [24]

An altered state of consciousness can be defined as any state of consciousness that deviates from normal waking consciousness, in terms of marked differences in our level of awareness, perceptions, memories, thinking, emotions, behaviours and sense of time, place and self-control.

Read more on Brainly.com - brainly.com/question/14823138#readmore

3 0

3 years ago