Which of the following does a bacteria cell NOT have in common with a plant cell?

What is 32,000,000 in scientific notation

jolli1 [7]

3.2 x10000000

the correct answer is 3.2x 10⁷

4 0

3 years ago

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Which metal is more active than NI and less active than Zn?

Mademuasel [1]

Answer : The correct option is, (2) Cr (Chromium)

Explanation :

The reactivity series of metal are arranged of the reactivity from the highest to the lowest. Reactivity series is used to determine the products of the single displacement reactions. In the single displacement reaction, the most reactive metal displaces the least reactive metal.

From the given reactivity series we conclude that there are two metal (Mg and Cr) are more reactive metal than the Ni and there are two metal (Pb and Cr) are less reactive metal than the Zn. So, the Cr (Chromium) is the metal which is more active than Ni and less active than Zn.

Hence, the correct option is, (2) Cr

7 0

4 years ago

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A volume of 120 mL of H2O is initially at room temperature (22.00 ∘C ). A chilled steel rod at 2.00 ∘C ∘C is placed in the water

aliina [53]

Answer:

$\large \boxed{\text{28.5 g}}$

Explanation:

There are two heat flows in this process and, since energy (heat) can neither be destroyed nor created, the energy change for the system must equal zero.

Data:

For Fe, m₁ = ?; C₁ = 0.452 J°C⁻¹g⁻¹; Ti = 2.00 °C; T_f = 21.50 °C

For H₂O, m₂ = 120 g; C₂ = 4.18 J°C⁻¹g⁻¹; Ti = 22.00 °C; T_f = 21.50 °C

Calculations:

1. Temperature changes

ΔT₁ = T_f - Ti = 21.50 °C - 2.00 °C = 19.50 °C

ΔT₂ = T_f - Ti = 21.50 °C - 22.00 °C = -0.50 °C

2. Mass of steel rod

$\begin{array}{ccl}\text{Heat gained by steel rod + heat lost by water} & = & 0\\m_{1}C_{1} \Delta T_{1} + m_{2}C_{2} \Delta T_{2}& = & 0\\m_{1} \times 0.452 \text{ J$^{\circ}$C$^{-1}$g$^{-1}$}\times 19.50 \, ^{\circ}\text{C} + \text{120 g} \times 4.18\text{ J$^{\circ}$C$^{-1}$g$^{-1}$} \times (-0.50)\, ^{\circ}\text{C}& = & 0\\8.814m_{1}\text{ g}^{-1} - 250.8 & = &0\\\end{array}\\$

$\begin{array}{ccl}8.814m_{1}\text{ g}^{-1} & = &250.8\\m_{1} & = & \dfrac{250.8}{\text{8.814 g}^{-1}}\\\\& = & \textbf{28.5 g}\\\end{array}\\\text{The mass of the steel rod is $\large \boxed{\textbf{28.5 g}}$}$

6 0

3 years ago

Describe two tests that you can run to determine if something is a substance or a mixture.

ryzh [129]

The difference between a substance and a mixture is that a substance is one of a kind, a material of the same composition throughout, on the contrary, a mixture is one or more different substances brought together and mixed together without changing the nature of each single substance.

One way to test it is to take two substances like sand and table salt. They should each be in granular form and in adequate amount to mix. Neither substance has changed after mixing the two. Even though it may not be easy or convenient to accomplish, each substance could be separated out from the mixture.

When it comes to two substances in lump form, it would not be a mixture when one lump is positioned next to the other lump because there are not enough pieces to combine.

However, there could be a mixture of three substances, like sand, table salt and graphite powder and there could be a mixture with four substances, etc., ad infinitum.

Mixtures are of solid substances in general. On the other hand, one starts referring to solutions when liquids are involved. Gases can be a mixture like for example, air is a mixture with nitrogen, oxygen, argon, etc.

4 0

3 years ago

Classify these substances. More than one answer may apply in each case.

enyata [817]

Answer: $H_2$ : Pure substance, Element

$O_2$ : Pure substance , Element

$H_2O$ : Pure substance, Compound

Explanation:

Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: $H-2$ and $O_2$

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: $H_2O$

Heterogeneous Mixture : Mixture that has its different components mixed unevenly within the substance . Example: Air

Homogeneous Mixture : Mixture that has its different components mixed evenly within the substance. Example: sugar dissolved in water

3 0

4 years ago