<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>0010 - Disclosure - 5. Property and equipment</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>From2013-01-01to2013-06-30</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0000828878</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>us-gaap_PropertyPlantAndEquipmentAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Property, Plant and Equipment [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="From2013-01-01to2013-06-30" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;p style="font: 8pt Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;Property, Plant &amp;#38; Equipment consisted of
the following:&lt;/p&gt;

&lt;p style="font: 8pt Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&amp;#160;&lt;/p&gt;

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    &lt;td colspan="2" style="border-bottom: black 1.5pt solid; text-align: center"&gt;&lt;font style="font-size: 8pt"&gt;&lt;b&gt;June 30, 2013&lt;/b&gt;&lt;/font&gt;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td colspan="2" style="border-bottom: black 1.5pt solid; text-align: center"&gt;&lt;font style="font-size: 8pt"&gt;&lt;b&gt;December 31, 2012&lt;/b&gt;&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom"&gt;
    &lt;td style="width: 81%"&gt;&lt;font style="font-size: 8pt"&gt;Building&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 1%"&gt;&lt;font style="font-size: 8pt"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 8%; text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;15,984&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 1%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="width: 1%"&gt;&lt;font style="font-size: 8pt"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 8%; text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;15,746&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom"&gt;
    &lt;td&gt;&lt;font style="font-size: 8pt"&gt;Automobile&lt;/font&gt;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;1,199,840&lt;/font&gt;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;1,181,987&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom"&gt;
    &lt;td&gt;&lt;font style="font-size: 8pt"&gt;Office equipment &amp;#38; Furniture&lt;/font&gt;&lt;/td&gt;
    &lt;td style="border-bottom: black 1.5pt solid"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1.5pt solid; text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;582,065&lt;/font&gt;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1.5pt solid"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1.5pt solid; text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;562,240&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom"&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;1,797,889&lt;/font&gt;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;1,759,973&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom"&gt;
    &lt;td&gt;&lt;font style="font-size: 8pt"&gt;Accumulated depreciation&lt;/font&gt;&lt;/td&gt;
    &lt;td style="border-bottom: black 1.5pt solid"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1.5pt solid; text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;(1,563,146)&lt;/font&gt;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1.5pt solid"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1.5pt solid; text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;(1,530,913)&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom"&gt;
    &lt;td&gt;&lt;font style="font-size: 8pt"&gt;Property and equipment, net&lt;/font&gt;&lt;/td&gt;
    &lt;td style="border-bottom: black 2.25pt double"&gt;&lt;font style="font-size: 8pt"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="border-bottom: black 2.25pt double; text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;234,743&lt;/font&gt;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 2.25pt double"&gt;&lt;font style="font-size: 8pt"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="border-bottom: black 2.25pt double; text-align: right"&gt;&lt;font style="font-size: 8pt"&gt;229,061&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
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&lt;p style="font: 8pt Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 8pt Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;The Company recorded depreciation expense relating
to properties held for rental, as well as property and equipment amounting to $1,642,147 and $1,622,687 for the months ended June
30, 2013 and 2012, respectively, of which, $8,058 and $44,053 were recorded as general and administrative expense, respectively.&lt;/p&gt;

&lt;p style="font: 8pt Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 8pt Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;As of June 30, 2013, fixed assets and rental
property totaling $31,827,386 were pledged as security for various bank loans totaling $21,474,892.&lt;/p&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>The entire disclosure for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, accounting policies and methodology, roll forwards, depreciation, depletion and amortization expense, including composite depreciation, accumulated depreciation, depletion and amortization expense, useful lives and method used, income statement disclosures, assets held for sale and public utility disclosures.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef

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